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Average Weather in Lewiston Utah, United States

In Lewiston, the summers are hot and mostly clear, the winters are freezing and partly cloudy, and it is dry year round. Over the course of the year, the temperature typically varies from 16°F to 89°F and is rarely below 1°F or above 95°F.

Based on the tourism score, the best time of year to visit Lewiston for warm-weather activities is from late June to late August.

Climate Summary

very coldcoldcoolwarmhotwarmcoolcoldJanFebMarAprMayJunJulAugSepOctNovDec80%80%45%45%clearovercastprecipitation: 1.8 inprecipitation: 1.8 in0.5 in0.5 inmuggy: 0%muggy: 0%0%0%drydrytourism score: 6.7tourism score: 6.70.00.0
Click on each chart for more information.

Temperature

The hot season lasts for 3.1 months, from June 10 to September 15, with an average daily high temperature above 78°F. The hottest day of the year is July 26, with an average high of 89°F and low of 54°F.

The cold season lasts for 3.1 months, from November 24 to February 27, with an average daily high temperature below 42°F. The coldest day of the year is January 7, with an average low of 16°F and high of 31°F.

Average High and Low Temperature

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.

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

Average Hourly Temperature in LewistonJanFebMarAprMayJunJulAugSepOctNovDec12 AM4 AM8 AM12 PM4 PM8 PM12 AMfreezingfreezingvery coldcoldcoldcoolwarmhotvery coldcomfortablecomfortable
The average hourly temperature, color coded into bands: 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 shaded overlays indicate night and civil twilight.

Cimin, Turkey (6,525 miles away) and Bījār, Iran (6,912 miles) are the far-away foreign places with temperatures most similar to Lewiston (view comparison).

Clouds

In Lewiston, 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 Lewiston begins around June 5 and lasts for 4.4 months, ending around October 19. On July 27, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 80% of the time, and overcast or mostly cloudy 20% of the time.

The cloudier part of the year begins around October 19 and lasts for 7.6 months, ending around June 5. On March 3, the cloudiest day of the year, the sky is overcast or mostly cloudy 55% of the time, and clear, mostly clear, or partly cloudy 45% of the time.

Cloud Cover Categories

Cloud Cover Categories in LewistonclearercloudiercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Jul 2780%Jul 2780%Mar 345%Mar 345%Jun 562%Jun 562%Oct 1963%Oct 1963%clearpartly cloudyovercastmostly clearmostly cloudy
The percentage of time spent in each cloud cover band, categorized by the percentage of the sky covered by clouds: clear < 20% < mostly clear < 40% < partly cloudy < 60% < mostly cloudy < 80% < overcast.

Precipitation

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

The wetter season lasts 8.7 months, from September 21 to June 12, with a greater than 17% chance of a given day being a wet day. The chance of a wet day peaks at 26% on May 4.

The drier season lasts 3.3 months, from June 12 to September 21. The smallest chance of a wet day is 8% on July 4.

Among wet days, we distinguish between those that experience rain alone, snow alone, or a mixture of the two. Based on this categorization, the most common form of precipitation in Lewiston changes throughout the year.

Rain alone is the most common for 11 months, from February 3 to December 21. The highest chance of a day with rain alone is 25% on May 20.

Mixed snow and rain is the most common for 3.9 weeks, from January 7 to February 3. The highest chance of a day with mixed snow and rain is 8% on January 8.

Snow alone is the most common for 2.4 weeks, from December 21 to January 7. The highest chance of a day with snow alone is 9% on December 28.

Daily Chance of Precipitation

Daily Chance of Precipitation in LewistonrainJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%May 426%May 426%Jul 48%Jul 48%Jan 721%Jan 721%Dec 2122%Dec 2122%Sep 2117%Sep 2117%rainsnowmixed
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).

Rainfall

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. Lewiston experiences some seasonal variation in monthly rainfall.

Rain falls throughout the year in Lewiston. The most rain falls during the 31 days centered around May 18, with an average total accumulation of 1.8 inches.

The least rain falls around July 9, with an average total accumulation of 0.5 inches.

Average Monthly Rainfall

Average Monthly Rainfall in LewistonJanFebMarAprMayJunJulAugSepOctNovDec0.0 in0.5 in1.0 in1.5 in2.0 in2.5 in3.0 in3.5 inMay 181.8 inMay 181.8 inJul 90.5 inJul 90.5 inOct 51.3 inOct 51.3 inJan 290.7 inJan 290.7 in
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 liquid-equivalent snowfall.

Snowfall

We report snowfall in liquid-equivalent terms. The actual depth of new snowfall is typically between 5 and 10 times the liquid-equivalent amount, assuming the ground is frozen. Colder, drier snow tends to be on the higher end of that range and warmer, wetter snow on the lower end.

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

The snowy period of the year lasts for 5.0 months, from October 30 to March 28, with a sliding 31-day liquid-equivalent snowfall of at least 0.1 inches. The most snow falls during the 31 days centered around January 5, with an average total liquid-equivalent accumulation of 0.6 inches.

The snowless period of the year lasts for 7.0 months, from March 28 to October 30. The least snow falls around August 4, with an average total liquid-equivalent accumulation of 0.0 inches.

Average Liquid-Equivalent Monthly Snowfall

Average Liquid-Equivalent Monthly Snowfall in LewistonsnowsnowJanFebMarAprMayJunJulAugSepOctNovDec0.0 in0.5 in1.0 in1.5 in2.0 inJan 50.6 inJan 50.6 inAug 40.0 inAug 40.0 inOct 300.1 inOct 300.1 inMar 280.1 inMar 280.1 in
The average liquid-equivalent 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.

Sun

The length of the day in Lewiston varies significantly over the course of the year. In 2018, the shortest day is December 21, with 9 hours, 7 minutes of daylight; the longest day is June 21, with 15 hours, 14 minutes of daylight.

Hours of Daylight and Twilight

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.

The earliest sunrise is at 5:51 AM on June 14, and the latest sunrise is 2 hours, 11 minutes later at 8:02 AM on November 3. The earliest sunset is at 4:55 PM on December 8, and the latest sunset is 4 hours, 11 minutes later at 9:07 PM on June 27.

Daylight saving time (DST) is observed in Lewiston during 2018, starting in the spring on March 11, lasting 7.8 months, and ending in the fall on November 4.

Sunrise & Sunset with Twilight and Daylight Saving Time

Sunrise & Sunset with Twilight and Daylight Saving Time in LewistonJanFebMarAprMayJunJulAugSepOctNovDec2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 145:51 AMJun 145:51 AM9:07 PMJun 279:07 PMJun 27Dec 84:55 PMDec 84:55 PM8:02 AMNov 38:02 AMNov 3Mar 11DSTMar 11DSTDSTNov 4DSTNov 4daynightnightnightnightSolarMidnightSolarMidnightSolarNoonSunriseSunset
The solar day over the course of the year 2018. 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.

Humidity

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 Lewiston, 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

Humidity Comfort Levels in LewistonJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Jan 290%Jan 290%Aug 80%Aug 80%drydry
The percentage of time spent at various humidity comfort levels, categorized by dew point: dry < 55°F < comfortable < 60°F < humid < 65°F < muggy < 70°F < oppressive < 75°F < miserable.

Wind

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 Lewiston experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 4.0 months, from February 25 to June 27, with average wind speeds of more than 6.7 miles per hour. The windiest day of the year is March 30, with an average hourly wind speed of 7.4 miles per hour.

The calmer time of year lasts for 8.0 months, from June 27 to February 25. The calmest day of the year is August 4, with an average hourly wind speed of 6.0 miles per hour.

Average Wind Speed

Average Wind Speed in LewistonwindyJanFebMarAprMayJunJulAugSepOctNovDec0 mph2 mph4 mph6 mph8 mph10 mph12 mphMar 307.4 mphMar 307.4 mphAug 46.0 mphAug 46.0 mph
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The predominant average hourly wind direction in Lewiston varies throughout the year.

The wind is most often from the west for 4.8 months, from March 16 to August 11 and for 1.1 months, from September 9 to October 12, with a peak percentage of 38% on May 4. The wind is most often from the south for 4.1 weeks, from August 11 to September 9 and for 5.1 months, from October 12 to March 16, with a peak percentage of 34% on September 2.

Wind Direction

Wind Direction in LewistonSWSWSJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%westsoutheastnorth
The percentage of hours in which the mean wind direction is from each of the four cardinal wind directions (north, east, south, and west), excluding hours in which the mean wind speed is less than 1 mph. The lightly tinted areas at the boundaries are the percentage of hours spent in the implied intermediate directions (northeast, southeast, southwest, and northwest).

Best Time of Year to Visit

To characterize how pleasant the weather is in Lewiston 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 Lewiston for general outdoor tourist activities is from late June to late August, with a peak score in the last week of July.

Tourism Score

Tourism Score in Lewistonbest timeJanFebMarAprMayJunJulAugSepOctNovDec02468106.76.70.00.0precipitationprecipitationcloudscloudstemperaturetemperaturetourism 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 Lewiston for hot-weather activities is from early July to mid August, with a peak score in the last week of July.

Beach/Pool Score

Beach/Pool Score in LewistonJanFebMarAprMayJunJulAugSepOctNovDec02468104.04.00.00.0 precipitationprecipitationcloudscloudstemperaturetemperaturebeach/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.

Growing Season

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 Lewiston typically lasts for 4.6 months (140 days), from around May 11 to around September 28, rarely starting before April 21 or after May 29, and rarely ending before September 11 or after October 16.

Time Spent in Various Temperature Bands and the Growing Season

Time Spent in Various Temperature Bands and the Growing Season in Lewistongrowing seasonJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%May 1150%May 1150%Sep 2850%Sep 2850%May 2990%May 2990%Sep 1190%Sep 1190%Apr 2110%Apr 2110%Oct 1610%Oct 1610%0%Feb 150%Feb 15Jul 27100%Jul 27100%freezingvery coldcoolcomfortablewarmcoldfrigidhot
The percentage of time spent in various temperature bands: 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 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 Lewiston should appear around April 23, only rarely appearing before April 9 or after May 10.

Growing Degree Days

The average growing degree days accumulated over the course of the year, with 25th to 75th and 10th to 90th percentile bands.

Solar Energy

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 3.0 months, from May 19 to August 17, with an average daily incident shortwave energy per square meter above 7.1 kWh. The brightest day of the year is June 29, with an average of 8.4 kWh.

The darker period of the year lasts for 3.5 months, from October 30 to February 14, with an average daily incident shortwave energy per square meter below 3.3 kWh. The darkest day of the year is December 21, with an average of 2.0 kWh.

Average Daily Incident Shortwave Solar Energy

Average Daily Incident Shortwave Solar Energy in LewistonbrightdarkdarkJanFebMarAprMayJunJulAugSepOctNovDec0 kWh1 kWh2 kWh3 kWh4 kWh5 kWh6 kWh7 kWh8 kWh9 kWh10 kWhJun 298.4 kWhJun 298.4 kWhDec 212.0 kWhDec 212.0 kWhAug 177.1 kWhAug 177.1 kWhOct 303.3 kWhOct 303.3 kWhFeb 143.3 kWhFeb 143.3 kWh
The average daily shortwave solar energy reaching the ground per square meter (orange line), with 25th to 75th and 10th to 90th percentile bands.

Topography

For the purposes of this report, the geographical coordinates of Lewiston are 41.976 deg latitude, -111.856 deg longitude, and 4,501 ft elevation.

The topography within 2 miles of Lewiston is essentially flat, with a maximum elevation change of 75 feet and an average elevation above sea level of 4,500 feet. Within 10 miles is essentially flat (5,322 feet). Within 50 miles also contains extreme variations in elevation (5,722 feet).

The area within 2 miles of Lewiston is covered by cropland (88%), within 10 miles by cropland (56%) and shrubs (24%), and within 50 miles by shrubs (50%) and cropland (18%).

Data Sources

This report illustrates the typical weather in Lewiston, 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 3 weather stations near enough to contribute to our estimation of the temperature and dew point in Lewiston.

For each station, the records are corrected for the elevation difference between that station and Lewiston 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 Lewiston is computed as the weighted average of the individual contributions from each station, with weights proportional to the inverse of the distance between Lewiston and a given station.

The stations contributing to this reconstruction are: Logan-Cache Airport (69%, 21 kilometers, south); Malad City Airport (26%, 40 kilometers, northwest); and Afton Municipal Airport (4.9%, 111 kilometers, northeast).

Other Data

All data relating to the Sun's position (e.g., sunrise and sunset) are computed using astronomical formulas from the book, Astronomical Tables of the Sun, Moon and Planets , 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 aiports and weather stations are provided by AskGeo.com .

Maps are © Esri, with data from National Geographic, Esri, DeLorme, NAVTEQ, UNEP-WCMC, USGS, NASA, ESA, METI, NRCAN, GEBCO, NOAA, and iPC.

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.