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Winter Weather in San Luis Obispo California, United States

Daily high temperatures are around 64°F, rarely falling below 55°F or exceeding 75°F. The lowest daily average high temperature is 63°F on December 24.

Daily low temperatures are around 43°F, rarely falling below 33°F or exceeding 53°F. The lowest daily average low temperature is 41°F on December 26.

For reference, on August 23, the hottest day of the year, temperatures in San Luis Obispo typically range from 55°F to 78°F, while on December 26, the coldest day of the year, they range from 41°F to 63°F.

Average High and Low Temperature in the Winter in San Luis Obispo

Average High and Low Temperature in the Winter in San Luis ObispoDecJanFeb30°F30°F35°F35°F40°F40°F45°F45°F50°F50°F55°F55°F60°F60°F65°F65°F70°F70°F75°F75°F80°F80°F85°F85°FFallSpringDec 2363°FDec 2363°F41°F41°FDec 166°FDec 166°F43°F43°FFeb 2865°FFeb 2865°F45°F45°FFeb 164°FFeb 164°F43°F43°F
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 winter 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 Winter in San Luis Obispo

Average Hourly Temperature in the Winter in San Luis ObispoDecJanFeb12 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 AMFallSpringvery coldcoldcoldcoolcomfortable
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.

Hacienda La Calera, Chile (5,695 miles away); Campos do Jordão, Brazil (6,341 miles); and Stutterheim, South Africa (10,617 miles) are the far-away foreign places with temperatures most similar to San Luis Obispo (view comparison).

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The winter in San Luis Obispo experiences gradually increasing cloud cover, with the percentage of time that the sky is overcast or mostly cloudy increasing from 40% to 46%. The highest chance of overcast or mostly cloudy conditions is 47% on February 17.

The clearest day of the winter is December 1, with clear, mostly clear, or partly cloudy conditions 60% of the time.

For reference, on February 17, the cloudiest day of the year, the chance of overcast or mostly cloudy conditions is 47%, while on August 23, the clearest day of the year, the chance of clear, mostly clear, or partly cloudy skies is 92%.

Cloud Cover Categories in the Winter in San Luis Obispo

Cloud Cover Categories in the Winter in San Luis ObispoDecJanFeb0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%FallSpringAug 2392%Aug 2392%Dec 160%Dec 160%Feb 2855%Feb 2855%Jan 155%Jan 155%Feb 156%Feb 156%clearmostly clearpartly cloudyovercastmostly cloudy
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 Luis Obispo, the chance of a wet day over the course of the winter is rapidly increasing, starting the season at 15% and ending it at 22%.

For reference, the year's highest daily chance of a wet day is 24% on February 20, and its lowest chance is 0% on July 29.

Probability of Precipitation in the Winter in San Luis Obispo

Probability of Precipitation in the Winter in San Luis ObispoDecJanFeb0%0%5%5%10%10%15%15%20%20%25%25%FallSpringFeb 2024%Feb 2024%Dec 115%Dec 115%Jan 120%Jan 120%Feb 120%Feb 120%rain
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 winter in San Luis Obispo is rapidly increasing, starting the season at 1.6 inches, when it rarely exceeds 3.6 inches or falls below 0.1 inches, and ending the season at 2.9 inches, when it rarely exceeds 6.2 inches or falls below 0.3 inches.

The highest average 31-day accumulation is 3.0 inches on February 17.

Average Monthly Rainfall in the Winter in San Luis Obispo

Average Monthly Rainfall in the Winter in San Luis ObispoDecJanFeb0 in0 in1 in1 in2 in2 in3 in3 in4 in4 in5 in5 in6 in6 in7 in7 inFallSpringFeb 163.0 inFeb 163.0 inDec 11.6 inDec 11.6 inJan 12.6 inJan 12.6 inFeb 12.7 inFeb 12.7 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 snowfall.

Over the course of the winter in San Luis Obispo, the length of the day is rapidly increasing. From the start to the end of the season, the length of the day increases by 1 hour, 28 minutes, implying an average daily increase of 59 seconds, and weekly increase of 6 minutes, 55 seconds.

The shortest day of the winter is December 20, with 9 hours, 47 minutes of daylight and the longest day is February 28, with 11 hours, 25 minutes of daylight.

Hours of Daylight and Twilight in the Winter in San Luis Obispo

Hours of Daylight and Twilight in the Winter in San Luis ObispoDecJanFeb0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hrFallSpringDec 219 hr, 47 minDec 219 hr, 47 minnightnightdaydayFeb 2811 hr, 25 minFeb 2811 hr, 25 minFeb 110 hr, 30 minFeb 110 hr, 30 min
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 winter in San Luis Obispo is 7:11 AM on January 7 and the earliest sunrise is 39 minutes earlier at 6:32 AM on February 28.

The earliest sunset is 4:50 PM on December 4 and the latest sunset is 1 hour, 8 minutes later at 5:57 PM on February 28.

Daylight saving time is observed in San Luis Obispo during 2024, but it neither starts nor ends during the winter, so the entire season is in daylight saving time.

For reference, on June 20, the longest day of the year, the Sun rises at 5:48 AM and sets 14 hours, 32 minutes later, at 8:20 PM, while on December 21, the shortest day of the year, it rises at 7:07 AM and sets 9 hours, 47 minutes later, at 4:54 PM.

Sunrise & Sunset with Twilight and Daylight Saving Time in the Winter in San Luis Obispo

Sunrise & Sunset with Twilight and Daylight Saving Time in the Winter in San Luis ObispoDecJanFeb12 AM2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMFallSpring6:32 AM6:32 AMFeb 285:57 PMFeb 285:57 PM6:56 AM6:56 AMDec 44:50 PMDec 44:50 PM7:11 AM7:11 AMJan 75:06 PMJan 75:06 PM7:01 AM7:01 AMFeb 15:31 PMFeb 15:31 PMSolarMidnightSolarMidnightSolarNoonSunriseSunset
The solar day in the winter. 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 Winter in San Luis Obispo

Solar Elevation and Azimuth in the Winter in San Luis ObispoDecJanFeb12 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 AMFallSpring0102030010203040
northeastsouthwest
Solar elevation and azimuth in the the winter 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 winter 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 Winter in San Luis Obispo

Moon Rise, Set & Phases in the Winter in San Luis ObispoDecJanFeb12 AM12 AM4 AM4 AM8 AM8 AM12 PM12 PM4 PM4 PM8 PM8 PM12 AM12 AMFallSpringNov 15:48 AMNov 15:48 AMNov 151:29 PMNov 151:29 PMNov 3010:22 PMNov 3010:22 PMDec 151:02 AMDec 151:02 AMDec 302:28 PMDec 302:28 PMJan 132:28 PMJan 132:28 PMJan 294:37 AMJan 294:37 AMFeb 125:54 AMFeb 125:54 AMFeb 274:45 PMFeb 274:45 PMMar 1311:55 PMMar 1311:55 PMMar 293:58 AMMar 293:58 AM6:05 PM6:05 PM6:31 AM6:31 AM4:16 PM4:16 PM4:06 PM4:06 PM7:43 AM7:43 AM7:20 AM7:20 AM4:44 PM4:44 PM5:01 PM5:01 PM8:05 AM8:05 AM7:29 AM7:29 AM5:53 PM5:53 PM5:00 PM5:00 PM7:09 AM7:09 AM5:53 PM5:53 PM6:53 PM6:53 PM7:26 AM7:26 AM8:05 PM8:05 PM
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 Luis Obispo is essentially constant during the winter, remaining around 0% throughout.

For reference, on July 12, the muggiest day of the year, there are muggy conditions 0% of the time, while on January 1, the least muggy day of the year, there are muggy conditions 0% of the time.

Humidity Comfort Levels in the Winter in San Luis Obispo

Humidity Comfort Levels in the Winter in San Luis ObispoDecJanFeb0%0%10%10%20%20%30%30%40%40%50%50%60%60%70%70%80%80%90%90%100%100%FallSpringJan 150%Jan 150%Dec 10%Dec 10%Feb 280%Feb 280%Jan 10%Jan 10%Feb 10%Feb 10%drydrycomfortablecomfortable
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 Luis Obispo is essentially constant during the winter, remaining within 0.3 miles per hour of 8.4 miles per hour throughout.

For reference, on May 23, the windiest day of the year, the daily average wind speed is 9.3 miles per hour, while on September 9, the calmest day of the year, the daily average wind speed is 7.0 miles per hour.

Average Wind Speed in the Winter in San Luis Obispo

Average Wind Speed in the Winter in San Luis ObispoDecJanFeb0 mph0 mph2 mph2 mph4 mph4 mph6 mph6 mph8 mph8 mph10 mph10 mph12 mph12 mph14 mph14 mphFallSpringDec 18.2 mphDec 18.2 mphFeb 288.6 mphFeb 288.6 mphJan 18.3 mphJan 18.3 mphFeb 18.3 mphFeb 18.3 mph
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 Luis Obispo throughout the winter is predominantly from the north, with a peak proportion of 44% on December 1.

Wind Direction in the Winter in San Luis Obispo

Wind Direction in the Winter in San Luis ObispoDecJanFeb0%100%20%80%40%60%60%40%80%20%100%0%FallSpringwestsoutheastnorth
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 Luis Obispo 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 Luis Obispo is gradually decreasing during the winter, falling by 2°F, from 58°F to 55°F, over the course of the season.

Average Water Temperature in the Winter in San Luis Obispo

Average Water Temperature in the Winter in San Luis ObispoDecJanFeb52°F52°F54°F54°F56°F56°F58°F58°F60°F60°F62°F62°FFallSpringDec 158°FDec 158°FFeb 2855°FFeb 2855°FJan 156°FJan 156°FFeb 156°FFeb 156°F
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).

The growing season in San Luis Obispo typically lasts for 11 months (329 days), from around January 24 to around December 18, rarely starting after March 3, or ending before November 21.

The smallest chance that a given day will be within the growing season in San Luis Obispo during the winter is 37% on January 5.

Time Spent in Various Temperature Bands and the Growing Season in the Winter in San Luis Obispo

Time Spent in Various Temperature Bands and the Growing Season in the Winter in San Luis ObispoDecJanFeb0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%FallSpring78%Dec 178%Dec 187%Feb 2887%Feb 28Jan 138%Jan 138%58%Feb 158%Feb 137%Jan 537%Jan 5very coldcoldcoolcomfortable
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 Luis Obispo are very rapidly decreasing during the winter, decreasing by 2,858°F, from 3,127°F to 268°F, over the course of the season.

Growing Degree Days in the Winter in San Luis Obispo

Growing Degree Days in the Winter in San Luis ObispoDecJanFeb500°F500°F1,000°F1,000°F1,500°F1,500°F2,000°F2,000°F2,500°F2,500°F3,000°F3,000°F3,500°F3,500°FFallSpringDec 13,127°FDec 13,127°FFeb 28268°FFeb 28268°F
The average growing degree days accumulated over the course of the winter, 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 Luis Obispo is increasing during the winter, rising by 1.5 kWh, from 2.9 kWh to 4.4 kWh, over the course of the season.

The lowest average daily incident shortwave solar energy during the winter is 2.7 kWh on December 23.

Average Daily Incident Shortwave Solar Energy in the Winter in San Luis Obispo

Average Daily Incident Shortwave Solar Energy in the Winter in San Luis ObispoDecJanFeb0 kWh0 kWh1 kWh1 kWh2 kWh2 kWh3 kWh3 kWh4 kWh4 kWh5 kWh5 kWh6 kWh6 kWh7 kWh7 kWhFallSpringDec 232.7 kWhDec 232.7 kWhDec 12.9 kWhDec 12.9 kWhFeb 284.4 kWhFeb 284.4 kWhFeb 13.4 kWhFeb 13.4 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.

For the purposes of this report, the geographical coordinates of San Luis Obispo are 35.283 deg latitude, -120.660 deg longitude, and 226 ft elevation.

The topography within 2 miles of San Luis Obispo contains very significant variations in elevation, with a maximum elevation change of 1,535 feet and an average elevation above sea level of 416 feet. Within 10 miles contains very significant variations in elevation (2,841 feet). Within 50 miles contains large variations in elevation (5,446 feet).

The area within 2 miles of San Luis Obispo is covered by artificial surfaces (60%) and grassland (29%), within 10 miles by grassland (50%) and shrubs (20%), and within 50 miles by grassland (38%) and water (35%).

This report illustrates the typical weather in San Luis Obispo, 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 San Luis Obispo.

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

The stations contributing to this reconstruction are:

To get a sense of how much these sources agree with each other, you can view a comparison of San Luis Obispo 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.

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