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Spring Weather in San Francisco Costa Rica

Daily high temperatures are around 81°F, rarely falling below 75°F or exceeding 86°F. The highest daily average high temperature is 82°F on April 8.

Daily low temperatures are around 65°F, rarely falling below 61°F or exceeding 68°F. The highest daily average low temperature is 65°F on May 7.

For reference, on April 6, the hottest day of the year, temperatures in San Francisco typically range from 65°F to 82°F, while on September 20, the coldest day of the year, they range from 64°F to 78°F.

Average High and Low Temperature in the Spring in San Francisco

Average High and Low Temperature in the Spring in San FranciscoMarAprMay60°F60°F65°F65°F70°F70°F75°F75°F80°F80°F85°F85°FWinterSummerApr 682°FApr 682°F65°F65°FMar 181°FMar 181°F64°F64°FMay 3179°FMay 3179°F65°F65°FMay 181°FMay 181°F65°F65°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.

The figure below shows you a compact characterization of the hourly average spring temperatures. The horizontal axis is the day, 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 the Spring in San Francisco

Average Hourly Temperature in the Spring in San FranciscoMarAprMay12 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 AMWinterSummerNowNowcoolcomfortablecomfortablewarm
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.

Kampala, Uganda (8,038 miles away) and Ambarita, Indonesia (11,550 miles) are the far-away foreign places with temperatures most similar to San Francisco (view comparison).

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The spring in San Francisco experiences very rapidly increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 47% to 95%.

The clearest day of the spring is March 1, with clear, mostly clear, or partly cloudy conditions 53% of the time.

For reference, on June 4, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 95%, while on January 2, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 64%.

Cloud Cover Categories in the Spring in San Francisco

Cloud Cover Categories in the Spring in San FranciscoMarAprMay0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%WinterSummerMar 153%Mar 153%May 315%May 315%Apr 139%Apr 139%May 115%May 115%NowNowclearmostly clearpartly 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.

A wet day is one with at least 0.04 inches of liquid or liquid-equivalent precipitation. In San Francisco, the chance of a wet day over the course of the spring is very rapidly increasing, starting the season at 8% and ending it at 43%.

For reference, the year's highest daily chance of a wet day is 51% on October 6, and its lowest chance is 6% on March 15.

Probability of Precipitation in the Spring in San Francisco

Probability of Precipitation in the Spring in San FranciscoMarAprMay0%0%5%5%10%10%15%15%20%20%25%25%30%30%35%35%40%40%45%45%WinterSummerMar 156%Mar 156%Mar 18%Mar 18%May 3143%May 3143%Apr 110%Apr 110%May 127%May 127%NowNowrain
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 season and not just the monthly totals, we show the rainfall accumulated over a sliding 31-day period centered around each day.

The average sliding 31-day rainfall during the spring in San Francisco is very rapidly increasing, starting the season at 0.7 inches, when it rarely exceeds 1.9 inches or falls below -0.0 inches, and ending the season at 5.6 inches, when it rarely exceeds 9.6 inches or falls below 2.0 inches.

The lowest average 31-day accumulation is 0.6 inches on March 15.

Average Monthly Rainfall in the Spring in San Francisco

Average Monthly Rainfall in the Spring in San FranciscoMarAprMay0 in0 in2 in2 in4 in4 in6 in6 in8 in8 in10 in10 inWinterSummerMar 140.6 inMar 140.6 inMar 10.7 inMar 10.7 inMay 315.6 inMay 315.6 inApr 11.0 inApr 11.0 inMay 13.3 inMay 13.3 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.

Over the course of the spring in San Francisco, the length of the day is increasing. From the start to the end of the season, the length of the day increases by 44 minutes, implying an average daily increase of 29 seconds, and weekly increase of 3 minutes, 22 seconds.

The shortest day of the spring is March 1, with 11 hours, 57 minutes of daylight and the longest day is May 31, with 12 hours, 40 minutes of daylight.

Hours of Daylight and Twilight in the Spring in San Francisco

Hours of Daylight and Twilight in the Spring in San FranciscoMarAprMay0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hrWinterSummerMar 1912 hr, 6 minMar 1912 hr, 6 minnightnightdaydayMay 3112 hr, 40 minMay 3112 hr, 40 minMay 112 hr, 29 minMay 112 hr, 29 minNowNow
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 latest sunrise of the spring in San Francisco is 5:50 AM on March 1 and the earliest sunrise is 36 minutes earlier at 5:14 AM on May 28.

The earliest sunset is 5:46 PM on April 11 and the latest sunset is 8 minutes later at 5:54 PM on May 31.

Daylight saving time is not observed in San Francisco during 2024.

For reference, on June 20, the longest day of the year, the Sun rises at 5:16 AM and sets 12 hours, 43 minutes later, at 5:59 PM, while on December 21, the shortest day of the year, it rises at 5:48 AM and sets 11 hours, 33 minutes later, at 5:21 PM.

Sunrise & Sunset with Twilight in the Spring in San Francisco

Sunrise & Sunset with Twilight in the Spring in San FranciscoMarAprMay12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PMWinterSummer5:14 AM5:14 AMMay 285:53 PMMay 285:53 PM5:27 AM5:27 AMApr 115:46 PMApr 115:46 PM5:50 AM5:50 AMMar 15:47 PMMar 15:47 PM5:19 AM5:19 AMMay 15:48 PMMay 15:48 PMSolarMidnightSolarMidnightSolarNoonSunriseSunsetNowNow
The solar day in the spring. 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 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 the Spring in San Francisco

Solar Elevation and Azimuth in the Spring in San FranciscoMarAprMay12 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 AMWinterSummer00102020303040505060607000101020303040405060607080NowNow
northeastsouthwest
Solar elevation and azimuth in the the spring of 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 the spring of 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. The label associated with each bar indicates the date and time that the phase is obtained, and the companion time labels indicate the rise and set times of the Moon for the nearest time interval in which the moon is above the horizon.

Moon Rise, Set & Phases in the Spring in San Francisco

Moon Rise, Set & Phases in the Spring in San FranciscoMarAprMay12 AM12 AM4 AM4 AM8 AM8 AM12 PM12 PM4 PM4 PM8 PM8 PM12 AM12 AMWinterSummerFeb 95:00 PMFeb 95:00 PMFeb 246:31 AMFeb 246:31 AMMar 103:01 AMMar 103:01 AMMar 251:01 AMMar 251:01 AMApr 812:22 PMApr 812:22 PMApr 235:50 PMApr 235:50 PMMay 79:23 PMMay 79:23 PMMay 237:54 AMMay 237:54 AMJun 66:38 AMJun 66:38 AMJun 217:09 PMJun 217:09 PM5:45 AM5:45 AM5:44 PM5:44 PM5:21 PM5:21 PM6:03 AM6:03 AM6:00 AM6:00 AM6:21 PM6:21 PM5:31 PM5:31 PM5:49 AM5:49 AM5:18 AM5:18 AM5:56 PM5:56 PM5:42 PM5:42 PM5:41 AM5:41 AM4:41 AM4:41 AM5:16 PM5:16 PM5:06 AM5:06 AM5:09 AM5:09 AM6:22 PM6:22 PM5:57 PM5:57 PM5:42 AM5:42 AMNowNow
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 chance that a given day will be muggy in San Francisco is very rapidly increasing during the spring, rising from 6% to 60% over the course of the season.

For reference, on June 3, the muggiest day of the year, there are muggy conditions 60% of the time, while on January 24, the least muggy day of the year, there are muggy conditions 3% of the time.

Humidity Comfort Levels in the Spring in San Francisco

Humidity Comfort Levels in the Spring in San FranciscoMarAprMay0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%WinterSummerMar 16%Mar 16%May 3160%May 3160%Apr 111%Apr 111%May 130%May 130%NowNowmuggymuggyhumidhumidcomfortablecomfortabledrydryoppressiveoppressive
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.

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 San Francisco is decreasing during the spring, decreasing from 3.9 miles per hour to 2.0 miles per hour over the course of the season.

For reference, on February 5, the windiest day of the year, the daily average wind speed is 4.0 miles per hour, while on September 17, the calmest day of the year, the daily average wind speed is 1.9 miles per hour.

Average Wind Speed in the Spring in San Francisco

Average Wind Speed in the Spring in San FranciscoMarAprMay0 mph0 mph1 mph1 mph2 mph2 mph3 mph3 mph4 mph4 mph5 mph5 mph6 mph6 mphWinterSummerMar 13.9 mphMar 13.9 mphMay 312.0 mphMay 312.0 mphApr 13.2 mphApr 13.2 mphMay 12.6 mphMay 12.6 mphNowNow
The average of mean hourly wind speeds (dark gray line), with 25th to 75th and 10th to 90th percentile bands.

The hourly average wind direction in San Francisco throughout the spring is predominantly from the east, with a peak proportion of 68% on March 1.

Wind Direction in the Spring in San Francisco

Wind Direction in the Spring in San FranciscoMarAprMay0%100%20%80%40%60%60%40%80%20%100%0%WinterSummerNowNowwesteastnorthsouth
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).

San Francisco is located near a large body of water (e.g., ocean, sea, or large lake). This section reports on the wide-area average surface temperature of that water.

The average surface water temperature in San Francisco is essentially constant during the spring, remaining within 1°F of 84°F throughout.

The highest average surface water temperature during the spring is 84°F on May 5.

Average Water Temperature in the Spring in San Francisco

Average Water Temperature in the Spring in San FranciscoMarAprMay81.0°F81.0°F81.5°F81.5°F82.0°F82.0°F82.5°F82.5°F83.0°F83.0°F83.5°F83.5°F84.0°F84.0°F84.5°F84.5°F85.0°F85.0°F85.5°F85.5°FWinterSummerMay 584°FMay 584°FMar 183°FMar 183°FMay 3184°FMay 3184°FApr 184°FApr 184°FNowNow
The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

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).

Temperatures in San Francisco are sufficiently warm year round that it is not entirely meaningful to discuss the growing season in these terms. We nevertheless include the chart below as an illustration of the distribution of temperatures experienced throughout the year.

Time Spent in Various Temperature Bands and the Growing Season in the Spring in San Francisco

Time Spent in Various Temperature Bands and the Growing Season in the Spring in San FranciscoMarAprMay0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%WinterSummer100%Apr 16100%Apr 16NowNowcoolcomfortablewarm
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.

The average accumulated growing degree days in San Francisco are very rapidly increasing during the spring, increasing by 1,944°F, from 1,215°F to 3,159°F, over the course of the season.

Growing Degree Days in the Spring in San Francisco

Growing Degree Days in the Spring in San FranciscoMarAprMay1,500°F1,500°F2,000°F2,000°F2,500°F2,500°F3,000°F3,000°FWinterSummerMar 11,215°FMar 11,215°FMay 313,159°FMay 313,159°FApr 11,870°FApr 11,870°FMay 12,529°FMay 12,529°FNowNow
The average growing degree days accumulated over the course of the spring, 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 in San Francisco is very rapidly decreasing during the spring, falling by 2.6 kWh, from 6.6 kWh to 4.0 kWh, over the course of the season.

The highest average daily incident shortwave solar energy during the spring is 6.8 kWh on March 22.

Average Daily Incident Shortwave Solar Energy in the Spring in San Francisco

Average Daily Incident Shortwave Solar Energy in the Spring in San FranciscoMarAprMay0 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWh8 kWh8 kWhWinterSummerMar 226.8 kWhMar 226.8 kWhMar 16.6 kWhMar 16.6 kWhMay 314.0 kWhMay 314.0 kWhMay 15.4 kWhMay 15.4 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.

For the purposes of this report, the geographical coordinates of San Francisco are 9.993 deg latitude, -84.129 deg longitude, and 3,701 ft elevation.

The topography within 2 miles of San Francisco contains very significant variations in elevation, with a maximum elevation change of 846 feet and an average elevation above sea level of 3,599 feet. Within 10 miles contains very significant variations in elevation (7,510 feet). Within 50 miles also contains extreme variations in elevation (11,447 feet).

The area within 2 miles of San Francisco is covered by grassland (71%) and trees (26%), within 10 miles by grassland (46%) and trees (39%), and within 50 miles by trees (54%) and grassland (17%).

This report illustrates the typical weather in San Francisco, 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 is only a single weather station, Juan Santamaría International Airport, in our network suitable to be used as a proxy for the historical temperature and dew point records of San Francisco.

At a distance of 9 kilometers from San Francisco, closer than our threshold of 150 kilometers, this station is deemed sufficiently nearby to be relied upon as our primary source for temperature and dew point records.

The station records are corrected for the elevation difference between the station and San Francisco according to the International Standard Atmosphere , and by the relative change present in the MERRA-2 satellite-era reanalysis between the two locations.

Please note that the station records themselves may additionally have been back-filled using other nearby stations or the MERRA-2 reanalysis.

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.

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