1. WeatherSpark.com
  2. France
  3. Auvergne-Rhône-Alpes

Climate and Average Weather Year Round in La Roche-sur-Foron France

In La Roche-sur-Foron, the summers are comfortable, the winters are very cold and snowy, and it is partly cloudy year round. Over the course of the year, the temperature typically varies from 27°F to 78°F and is rarely below 18°F or above 87°F.

Based on the tourism score, the best time of year to visit La Roche-sur-Foron for warm-weather activities is from late June to early September.

Climate in La Roche-sur-Foron

very coldcoldcoolcomfortablewarmcoolcoldvery coldJanFebMarAprMayJunJulAugSepOctNovDecNowNow68%68%42%42%overcastclearprecipitation: 3.5 inprecipitation: 3.5 in2.6 in2.6 inmuggy: 0%muggy: 0%0%0%drydrytourism score: 7.2tourism score: 7.20.00.0
La Roche-sur-Foron weather by month. Click on each chart for more information.

The warm season lasts for 3.1 months, from June 5 to September 10, with an average daily high temperature above 70°F. The hottest month of the year in La Roche-sur-Foron is July, with an average high of 77°F and low of 57°F.

The cold season lasts for 3.4 months, from November 17 to February 29, with an average daily high temperature below 46°F. The coldest month of the year in La Roche-sur-Foron is January, with an average low of 27°F and high of 39°F.

Average High and Low Temperature in La Roche-sur-Foron

Average High and Low Temperature in La Roche-sur-ForonwarmcoldcoldJanFebMarAprMayJunJulAugSepOctNovDec0°F0°F10°F10°F20°F20°F30°F30°F40°F40°F50°F50°F60°F60°F70°F70°F80°F80°F90°F90°F100°F100°FJan 1538°FJan 1538°FAug 378°FAug 378°F27°F27°F57°F57°FJun 570°FJun 570°FSep 1070°FSep 1070°FNov 1746°FNov 1746°FFeb 2946°FFeb 2946°F51°F51°F51°F51°F34°F34°F30°F30°FNowNow
The daily average high (red line) and low (blue line) temperature, with 25th to 75th and 10th to 90th percentile bands. The thin dotted lines are the corresponding average perceived temperatures.
AverageJanFebMarAprMayJunJulAugSepOctNovDec
High 39°F42°F51°F58°F65°F72°F77°F76°F68°F58°F47°F40°F
Temp. 33°F35°F42°F49°F56°F63°F67°F66°F59°F51°F40°F34°F
Low 27°F29°F34°F40°F47°F53°F57°F56°F50°F43°F34°F29°F

The figure below shows you a compact characterization of the entire year of hourly average temperatures. The horizontal axis is the day of the year, the vertical axis is the hour of the day, and the color is the average temperature for that hour and day.

Average Hourly Temperature in La Roche-sur-Foron

Average Hourly Temperature in La Roche-sur-ForonJanFebMarAprMayJunJulAugSepOctNovDec12 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AMNowNowfreezingvery coldvery coldcoldcoldcoolcomfortablewarmfreezingfreezing
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The average hourly temperature, color coded into bands. The shaded overlays indicate night and civil twilight.

Hope, Canada (5,141 miles away) and Blowing Rock, North Carolina, United States (4,401 miles) are the far-away foreign places with temperatures most similar to La Roche-sur-Foron (view comparison).

Map
Marker
© OpenStreetMap contributors

Compare La Roche-sur-Foron to another city:

Map

In La Roche-sur-Foron, the average percentage of the sky covered by clouds experiences significant seasonal variation over the course of the year.

The clearer part of the year in La Roche-sur-Foron begins around June 17 and lasts for 3.0 months, ending around September 16.

The clearest month of the year in La Roche-sur-Foron is July, during which on average the sky is clear, mostly clear, or partly cloudy 67% of the time.

The cloudier part of the year begins around September 16 and lasts for 9.0 months, ending around June 17.

The cloudiest month of the year in La Roche-sur-Foron is November, during which on average the sky is overcast or mostly cloudy 57% of the time.

Cloud Cover Categories in La Roche-sur-Foron

Cloud Cover Categories in La Roche-sur-ForonclearercloudiercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Jul 2068%Jul 2068%Dec 3042%Dec 3042%Jun 1755%Jun 1755%Sep 1655%Sep 1655%NowNowclearmostly clearpartly cloudymostly cloudyovercast
0% clear 20% mostly clear 40% partly cloudy 60% mostly cloudy 80% overcast 100%
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds.
FractionJanFebMarAprMayJunJulAugSepOctNovDec
Cloudier 55%53%53%54%56%46%33%36%45%54%57%56%
Clearer 45%47%47%46%44%54%67%64%55%46%43%44%

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. The chance of wet days in La Roche-sur-Foron varies throughout the year.

The wetter season lasts 7.9 months, from April 28 to December 24, with a greater than 32% chance of a given day being a wet day. The month with the most wet days in La Roche-sur-Foron is May, with an average of 11.6 days with at least 0.04 inches of precipitation.

The drier season lasts 4.1 months, from December 24 to April 28. The month with the fewest wet days in La Roche-sur-Foron is February, with an average of 8.2 days with at least 0.04 inches of precipitation.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. The month with the most days of rain alone in La Roche-sur-Foron is May, with an average of 11.6 days. Based on this categorization, the most common form of precipitation throughout the year is rain alone, with a peak probability of 40% on May 24.

Daily Chance of Precipitation in La Roche-sur-Foron

Daily Chance of Precipitation in La Roche-sur-ForonwetdryJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%May 2440%May 2440%Mar 225%Mar 225%Dec 2432%Dec 2432%NowNowrainmixedsnow
The percentage of days in which various types of precipitation are observed, excluding trace quantities: rain alone, snow alone, and mixed (both rain and snow fell in the same day).
Days ofJanFebMarAprMayJunJulAugSepOctNovDec
Rain 6.5d6.2d8.1d8.9d11.6d11.0d9.7d9.2d8.9d9.7d8.1d7.5d
Mixed 1.9d1.5d0.6d0.2d0.0d0.0d0.0d0.0d0.0d0.0d0.6d1.5d
Snow 0.9d0.5d0.1d0.0d0.0d0.0d0.0d0.0d0.0d0.0d0.4d1.0d
Any 9.3d8.2d8.8d9.1d11.6d11.0d9.7d9.2d8.9d9.7d9.2d9.9d

To show variation within the months and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day of the year. La Roche-sur-Foron experiences some seasonal variation in monthly rainfall.

Rain falls throughout the year in La Roche-sur-Foron. The month with the most rain in La Roche-sur-Foron is October, with an average rainfall of 3.4 inches.

The month with the least rain in La Roche-sur-Foron is March, with an average rainfall of 2.6 inches.

Average Monthly Rainfall in La Roche-sur-Foron

Average Monthly Rainfall in La Roche-sur-ForonJanFebMarAprMayJunJulAugSepOctNovDec0 in0 in1 in1 in2 in2 in3 in3 in4 in4 in5 in5 in6 in6 in7 in7 inMay 293.5 inMay 293.5 inMar 82.5 inMar 82.5 inOct 103.4 inOct 103.4 inDec 153.1 inDec 153.1 inAug 52.7 inAug 52.7 inNowNow
The average rainfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average snowfall.
JanFebMarAprMayJunJulAugSepOctNovDec
Rainfall 2.8″2.6″2.6″2.8″3.3″3.3″2.9″2.8″3.2″3.4″3.1″3.1″

Snowfall

As with rainfall, we consider the snowfall accumulated over a sliding 31-day period centered around each day of the year. La Roche-sur-Foron experiences some seasonal variation in monthly snowfall.

The snowy period of the year lasts for 3.8 months, from November 12 to March 7, with a sliding 31-day snowfall of at least 1.0 inches. The month with the most snow in La Roche-sur-Foron is January, with an average snowfall of 3.8 inches.

The snowless period of the year lasts for 8.2 months, from March 7 to November 12. The least snow falls around July 30, with an average total accumulation of 0.0 inches.

Average Monthly Snowfall in La Roche-sur-Foron

Average Monthly Snowfall in La Roche-sur-ForonsnowsnowJanFebMarAprMayJunJulAugSepOctNovDec0 in0 in2 in2 in4 in4 in6 in6 in8 in8 in10 in10 inJan 23.8 inJan 23.8 inJul 300.0 inJul 300.0 inNov 121.0 inNov 121.0 inMar 71.0 inMar 71.0 inNowNow
The average snowfall (solid line) accumulated over the course of a sliding 31-day period centered on the day in question, with 25th to 75th and 10th to 90th percentile bands. The thin dotted line is the corresponding average rainfall.
JanFebMarAprMayJunJulAugSepOctNovDec
Snowfall 3.8″2.4″0.6″0.2″0.0″0.0″0.0″0.0″0.0″0.0″1.2″3.5″

The length of the day in La Roche-sur-Foron varies significantly over the course of the year. In 2024, the shortest day is December 21, with 8 hours, 38 minutes of daylight; the longest day is June 20, with 15 hours, 46 minutes of daylight.

Hours of Daylight and Twilight in La Roche-sur-Foron

Hours of Daylight and Twilight in La Roche-sur-ForonJanFebMarAprMayJunJulAugSepOctNovDec0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hr12 hr, 7 minMar 2012 hr, 7 minMar 2015 hr, 46 minJun 2015 hr, 46 minJun 2012 hr, 10 minSep 2212 hr, 10 minSep 228 hr, 38 minDec 218 hr, 38 minDec 21nightnightdayNowNow
The number of hours during which the Sun is visible (black line). From bottom (most yellow) to top (most gray), the color bands indicate: full daylight, twilight (civil, nautical, and astronomical), and full night.
Hours ofJanFebMarAprMayJunJulAugSepOctNovDec
Daylight 9.1h10.4h12.0h13.6h15.0h15.7h15.3h14.1h12.5h10.9h9.4h8.7h

The earliest sunrise is at 5:43 AM on June 15, and the latest sunrise is 2 hours, 34 minutes later at 8:16 AM on January 2. The earliest sunset is at 4:49 PM on December 10, and the latest sunset is 4 hours, 41 minutes later at 9:30 PM on June 26.

Daylight saving time (DST) is observed in La Roche-sur-Foron during 2024, starting in the spring on March 31, lasting 6.9 months, and ending in the fall on October 27.

Sunrise & Sunset with Twilight and Daylight Saving Time in La Roche-sur-Foron

Sunrise & Sunset with Twilight and Daylight Saving Time in La Roche-sur-ForonJanFebMarAprMayJunJulAugSepOctNovDec2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 155:43 AMJun 155:43 AM9:30 PMJun 269:30 PMJun 26Dec 104:49 PMDec 104:49 PM8:16 AMJan 28:16 AMJan 2Mar 31DSTMar 31DSTDSTOct 27DSTOct 27daynightnightnightnightSolarMidnightSolarMidnightSolarNoonSunriseSunsetNowNow
The solar day over the course of the year 2024. From bottom to top, the black lines are the previous solar midnight, sunrise, solar noon, sunset, and the next solar midnight. The day, twilights (civil, nautical, and astronomical), and night are indicated by the color bands from yellow to gray. The transitions to and from daylight saving time are indicated by the 'DST' labels.

The figure below presents a compact representation of the sun's elevation (the angle of the sun above the horizon) and azimuth (its compass bearing) for every hour of every day in the reporting period. The horizontal axis is the day of the year and the vertical axis is the hour of the day. For a given day and hour of that day, the background color indicates the azimuth of the sun at that moment. The black isolines are contours of constant solar elevation.

Solar Elevation and Azimuth in La Roche-sur-Foron

Solar Elevation and Azimuth in La Roche-sur-ForonJanFebMarAprMayJunJulAugSepOctNovDec12 AM12 AM2 AM2 AM4 AM4 AM6 AM6 AM8 AM8 AM10 AM10 AM12 PM12 PM2 PM2 PM4 PM4 PM6 PM6 PM8 PM8 PM10 PM10 PM12 AM12 AM000010101020202030303040405060000101010102020203030404050506067NowNow
northeastsouthwest
Solar elevation and azimuth over the course of the year 2024. The black lines are lines of constant solar elevation (the angle of the sun above the horizon, in degrees). The background color fills indicate the azimuth (the compass bearing) of the sun. The lightly tinted areas at the boundaries of the cardinal compass points indicate the implied intermediate directions (northeast, southeast, southwest, and northwest).

The figure below presents a compact representation of key lunar data for 2024. The horizontal axis is the day, the vertical axis is the hour of the day, and the colored areas indicate when the moon is above the horizon. The vertical gray bars (new Moons) and blue bars (full Moons) indicate key Moon phases.

Moon Rise, Set & Phases in La Roche-sur-Foron

The time in which the moon is above the horizon (light blue area), with new moons (dark gray lines) and full moons (blue lines) indicated. The shaded overlays indicate night and civil twilight.

We base the humidity comfort level on the dew point, as it determines whether perspiration will evaporate from the skin, thereby cooling the body. Lower dew points feel drier and higher dew points feel more humid. Unlike temperature, which typically varies significantly between night and day, dew point tends to change more slowly, so while the temperature may drop at night, a muggy day is typically followed by a muggy night.

The perceived humidity level in La Roche-sur-Foron, as measured by the percentage of time in which the humidity comfort level is muggy, oppressive, or miserable, does not vary significantly over the course of the year, remaining a virtually constant 0% throughout.

Humidity Comfort Levels in La Roche-sur-Foron

Humidity Comfort Levels in La Roche-sur-ForonJanFebMarAprMayJunJulAugSepOctNovDec0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%Jan 260%Jan 260%Jul 230%Jul 230%NowNowcomfortablecomfortabledrydryhumidhumid
dry 55°F comfortable 60°F humid 65°F muggy 70°F oppressive 75°F miserable
The percentage of time spent at various humidity comfort levels, categorized by dew point.
JanFebMarAprMayJunJulAugSepOctNovDec
Muggy days 0.0d0.0d0.0d0.0d0.0d0.0d0.1d0.1d0.0d0.0d0.0d0.0d

This section discusses the wide-area hourly average wind vector (speed and direction) at 10 meters above the ground. The wind experienced at any given location is highly dependent on local topography and other factors, and instantaneous wind speed and direction vary more widely than hourly averages.

The average hourly wind speed in La Roche-sur-Foron does not vary significantly over the course of the year, remaining within 0.4 miles per hour of 5.3 miles per hour throughout.

Average Wind Speed in La Roche-sur-Foron

Average Wind Speed in La Roche-sur-ForonJanFebMarAprMayJunJulAugSepOctNovDec0 mph0 mph1 mph1 mph2 mph2 mph3 mph3 mph4 mph4 mph5 mph5 mph6 mph6 mph7 mph7 mph8 mph8 mph9 mph9 mphApr 15.7 mphApr 15.7 mphAug 94.9 mphAug 94.9 mphNowNow
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.
JanFebMarAprMayJunJulAugSepOctNovDec
Wind Speed (mph) 5.35.55.65.55.35.35.25.05.15.15.15.3

The predominant average hourly wind direction in La Roche-sur-Foron varies throughout the year.

The wind is most often from the north for 3.9 weeks, from April 4 to May 1, with a peak percentage of 34% on April 18. The wind is most often from the west for 4.3 months, from May 1 to September 9, with a peak percentage of 39% on July 4. The wind is most often from the south for 6.8 months, from September 9 to April 4, with a peak percentage of 47% on January 1.

Wind Direction in La Roche-sur-Foron

Wind Direction in La Roche-sur-ForonSNWSJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%NowNowwestsoutheastnorth
northeastsouthwest
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions, excluding hours in which the mean wind speed is less than 1.0 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

To characterize how pleasant the weather is in La Roche-sur-Foron throughout the year, we compute two travel scores.

The tourism score favors clear, rainless days with perceived temperatures between 65°F and 80°F. Based on this score, the best time of year to visit La Roche-sur-Foron for general outdoor tourist activities is from late June to early September, with a peak score in the first week of August.

Tourism Score in La Roche-sur-Foron

Tourism Score in La Roche-sur-Foronbest timeJanFebMarAprMayJunJulAugSepOctNovDec002244668810107.27.20.00.0NowNowtemperaturetemperature cloudscloudsprecipitationprecipitationtourism score
The tourism score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

The beach/pool score favors clear, rainless days with perceived temperatures between 75°F and 90°F. Based on this score, the best time of year to visit La Roche-sur-Foron for hot-weather activities is from early July to mid August, with a peak score in the last week of July.

Beach/Pool Score in La Roche-sur-Foron

Beach/Pool Score in La Roche-sur-ForonJanFebMarAprMayJunJulAugSepOctNovDec002244668810105.25.20.00.0NowNowtemperaturetemperature cloudscloudsprecipitationprecipitationbeach/pool score
The beach/pool score (filled area), and its constituents: the temperature score (red line), the cloud cover score (blue line), and the precipitation score (green line).

Methodology

For each hour between 8:00 AM and 9:00 PM of each day in the analysis period (1980 to 2016), independent scores are computed for perceived temperature, cloud cover, and total precipitation. Those scores are combined into a single hourly composite score, which is then aggregated into days, averaged over all the years in the analysis period, and smoothed.

Our cloud cover score is 10 for fully clear skies, falling linearly to 9 for mostly clear skies, and to 1 for fully overcast skies.

Our precipitation score, which is based on the three-hour precipitation centered on the hour in question, is 10 for no precipitation, falling linearly to 9 for trace precipitation, and to 0 for 0.04 inches of precipitation or more.

Our tourism temperature score is 0 for perceived temperatures below 50°F, rising linearly to 9 for 65°F, to 10 for 75°F, falling linearly to 9 for 80°F, and to 1 for 90°F or hotter.

Our beach/pool temperature score is 0 for perceived temperatures below 65°F, rising linearly to 9 for 75°F, to 10 for 82°F, falling linearly to 9 for 90°F, and to 1 for 100°F or hotter.

Definitions of the growing season vary throughout the world, but for the purposes of this report, we define it as the longest continuous period of non-freezing temperatures (≥ 32°F) in the year (the calendar year in the Northern Hemisphere, or from July 1 until June 30 in the Southern Hemisphere).

The growing season in La Roche-sur-Foron typically lasts for 6.6 months (201 days), from around April 11 to around October 30, rarely starting before March 21 or after May 1, and rarely ending before October 9 or after November 20.

Time Spent in Various Temperature Bands and the Growing Season in La Roche-sur-Foron

Time Spent in Various Temperature Bands and the Growing Season in La Roche-sur-Forongrowing seasonJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%50%Apr 1150%Apr 1150%Oct 3050%Oct 3090%May 190%May 190%Oct 990%Oct 910%Mar 2110%Mar 2110%Nov 2010%Nov 200%Dec 270%Dec 27Jul 25100%Jul 25100%freezingvery coldcoldcoolcomfortablewarm
frigid 15°F freezing 32°F very cold 45°F cold 55°F cool 65°F comfortable 75°F warm 85°F hot 95°F sweltering
The percentage of time spent in various temperature bands. The black line is the percentage chance that a given day is within the growing season.

Growing degree days are a measure of yearly heat accumulation used to predict plant and animal development, and defined as the integral of warmth above a base temperature, discarding any excess above a maximum temperature. In this report, we use a base of 50°F and a cap of 86°F.

Based on growing degree days alone, the first spring blooms in La Roche-sur-Foron should appear around April 20, only rarely appearing before April 7 or after May 5.

Growing Degree Days in La Roche-sur-Foron

Growing Degree Days in La Roche-sur-ForonJanFebMarAprMayJunJulAugSepOctNovDec0°F0°F500°F500°F1,000°F1,000°F1,500°F1,500°F2,000°F2,000°F2,500°F2,500°FApr 2090°FApr 2090°FJul 9900°FJul 9900°FSep 31,800°FSep 31,800°FDec 312,173°FDec 312,173°F
The average growing degree days accumulated over the course of the year, with 25th to 75th and 10th to 90th percentile bands.

This section discusses the total daily incident shortwave solar energy reaching the surface of the ground over a wide area, taking full account of seasonal variations in the length of the day, the elevation of the Sun above the horizon, and absorption by clouds and other atmospheric constituents. Shortwave radiation includes visible light and ultraviolet radiation.

The average daily incident shortwave solar energy experiences extreme seasonal variation over the course of the year.

The brighter period of the year lasts for 3.2 months, from May 12 to August 18, with an average daily incident shortwave energy per square meter above 6.0 kWh. The brightest month of the year in La Roche-sur-Foron is July, with an average of 6.9 kWh.

The darker period of the year lasts for 3.5 months, from October 27 to February 13, with an average daily incident shortwave energy per square meter below 2.5 kWh. The darkest month of the year in La Roche-sur-Foron is December, with an average of 1.4 kWh.

Average Daily Incident Shortwave Solar Energy in La Roche-sur-Foron

Average Daily Incident Shortwave Solar Energy in La Roche-sur-ForonbrightdarkdarkJanFebMarAprMayJunJulAugSepOctNovDec0 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWh9 kWh9 kWhJul 57.1 kWhJul 57.1 kWhDec 221.3 kWhDec 221.3 kWhMay 126.0 kWhMay 126.0 kWhAug 186.0 kWhAug 186.0 kWhOct 272.5 kWhOct 272.5 kWhFeb 132.5 kWhFeb 132.5 kWhNowNow
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.
JanFebMarAprMayJunJulAugSepOctNovDec
Solar Energy (kWh) 1.72.63.95.16.16.96.96.04.63.01.91.4

For the purposes of this report, the geographical coordinates of La Roche-sur-Foron are 46.067 deg latitude, 6.312 deg longitude, and 1,801 ft elevation.

The topography within 2 miles of La Roche-sur-Foron contains very significant variations in elevation, with a maximum elevation change of 1,319 feet and an average elevation above sea level of 1,937 feet. Within 10 miles contains very significant variations in elevation (6,634 feet). Within 50 miles also contains extreme variations in elevation (15,079 feet).

The area within 2 miles of La Roche-sur-Foron is covered by grassland (43%), artificial surfaces (21%), cropland (20%), and trees (16%), within 10 miles by trees (39%) and grassland (24%), and within 50 miles by trees (43%) and grassland (20%).

This report illustrates the typical weather in La Roche-sur-Foron, based on a statistical analysis of historical hourly weather reports and model reconstructions from January 1, 1980 to December 31, 2016.

Temperature and Dew Point

There are 4 weather stations near enough to contribute to our estimation of the temperature and dew point in La Roche-sur-Foron.

For each station, the records are corrected for the elevation difference between that station and La Roche-sur-Foron according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.

The estimated value at La Roche-sur-Foron is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between La Roche-sur-Foron and a given station.

The stations contributing to this reconstruction are:

  • Annecy-Meythet (LFLP, 47%, 14 mi, southwest, -282 ft elevation change)
  • Aéroport Genève-Cointrin (LSGG, 39%, 15 mi, northwest, -390 ft elevation change)
  • Sion (LSMS, 8%, 49 mi, east, -220 ft elevation change)
  • Aosta Airport (LIMW, 7%, 55 mi, southeast, 7 ft elevation change)

Sources mapLFLP, 47%14 mi, -282 ftLSGG, 39%15 mi, -390 ftLSMS, 8%49 mi, -220 ftLIMW, 7%55 mi, 7 ft© OpenStreetMap contributors

To get a sense of how much these sources agree with each other, you can view a comparison of La Roche-sur-Foron and the stations that contribute to our estimates of its temperature history and climate. Please note that each source's contribution is adjusted for elevation and the relative change present in the MERRA-2 data.

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Algorithms 2nd Edition , by Jean Meeus.

All other weather data, including cloud cover, precipitation, wind speed and direction, and solar flux, come from NASA's MERRA-2 Modern-Era Retrospective Analysis . This reanalysis combines a variety of wide-area measurements in a state-of-the-art global meteorological model to reconstruct the hourly history of weather throughout the world on a 50-kilometer grid.

Land Use data comes from the Global Land Cover SHARE database , published by the Food and Agriculture Organization of the United Nations.

Elevation data comes from the Shuttle Radar Topography Mission (SRTM) , published by NASA's Jet Propulsion Laboratory.

Names, locations, and time zones of places and some airports come from the GeoNames Geographical Database .

Time zones for airports and weather stations are provided by AskGeo.com .

Maps are © OpenStreetMap contributors.

Disclaimer

The information on this site is provided as is, without any assurances as to its accuracy or suitability for any purpose. Weather data is prone to errors, outages, and other defects. We assume no responsibility for any decisions made on the basis of the content presented on this site.

We draw particular cautious attention to our reliance on the MERRA-2 model-based reconstructions for a number of important data series. While having the tremendous advantages of temporal and spatial completeness, these reconstructions: (1) are based on computer models that may have model-based errors, (2) are coarsely sampled on a 50 km grid and are therefore unable to reconstruct the local variations of many microclimates, and (3) have particular difficulty with the weather in some coastal areas, especially small islands.

We further caution that our travel scores are only as good as the data that underpin them, that weather conditions at any given location and time are unpredictable and variable, and that the definition of the scores reflects a particular set of preferences that may not agree with those of any particular reader.

Please review our full terms contained on our Terms of Service page.