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Average Weather in San Luis Arizona, United States

In San Luis, the summers are sweltering and arid, the winters are cool and dry, and it is mostly clear year round. Over the course of the year, the temperature typically varies from 46°F to 107°F and is rarely below 40°F or above 112°F.

Climate Summary

comfortablewarmhotswelteringhotwarmJanFebMarAprMayJunJulAugSepOctNovDec89%89%65%65%clearovercastprecipitation: 0.4 inprecipitation: 0.4 in0.0 in0.0 inmuggy: 50%muggy: 50%0%0%drydrybeach/pool score: 7.8beach/pool score: 7.80.40.4
Click on each chart for more information.

Based on the beach/pool score, the best times of year to visit San Luis for hot-weather activities are from late May to mid July and from early September to early October.

Temperature

The hot season lasts for 3.8 months, from May 31 to September 24, with an average daily high temperature above 99°F. The hottest day of the year is July 10, with an average high of 107°F and low of 81°F.

The cool season lasts for 3.0 months, from November 22 to February 20, with an average daily high temperature below 75°F. The coldest day of the year is December 27, with an average low of 46°F and high of 67°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 San LuisJanFebMarAprMayJunJulAugSepOctNovDec12 AM4 AM8 AM12 PM4 PM8 PM12 AMcoldcoldcoolcoolcoolcoolcomfortablewarmhothotswelteringcoldcomfortablecold
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.

Tindouf, Algeria (6,084 miles away) is the far-away foreign place with temperatures most similar to San Luis (view comparison).

Clouds

In San Luis, 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 San Luis begins around August 12 and lasts for 2.7 months, ending around November 2. On September 18, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 89% of the time, and overcast or mostly cloudy 11% of the time.

The cloudier part of the year begins around November 2 and lasts for 9.3 months, ending around August 12. On February 20, the cloudiest day of the year, the sky is overcast or mostly cloudy 35% of the time, and clear, mostly clear, or partly cloudy 65% of the time.

Cloud Cover Categories

Cloud Cover Categories in San LuisclearercloudiercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Sep 1889%Sep 1889%Feb 2065%Feb 2065%Aug 1277%Aug 1277%Nov 277%Nov 277%clearovercastmostly clear
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

San Luis does not experience significant seasonal variation in the frequency of wet days (i.e., those with greater than 0.04 inches of liquid or liquid-equivalent precipitation). The frequency ranges from 0% to 7%, with an average value of 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 throughout the year is rain alone, with a peak probability of 7% on August 22.

Daily Chance of Precipitation

Daily Chance of Precipitation in San LuisJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Aug 227%Aug 227%Jun 100%Jun 100%Jan 16%Jan 16%Jul 134%Jul 134%Mar 214%Mar 214%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 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. San Luis experiences some seasonal variation in monthly rainfall.

Rain falls throughout the year in San Luis. The most rain falls during the 31 days centered around December 18, with an average total accumulation of 0.4 inches.

The least rain falls around June 6, with an average total accumulation of 0.0 inches.

Average Monthly Rainfall

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.

Sun

The length of the day in San Luis varies significantly over the course of the year. In 2017, the shortest day is December 21, with 10 hours, 1 minute of daylight; the longest day is June 20, with 14 hours, 17 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 5:31 AM on June 11, and the latest sunrise is 2 hours, 10 minutes later at 7:41 AM on January 7. The earliest sunset is at 5:33 PM on December 3, and the latest sunset is 2 hours, 17 minutes later at 7:50 PM on June 29.

Daylight saving time (DST) is not observed in San Luis during 2017.

Sunrise & Sunset with Twilight

Sunrise & Sunset with Twilight in San LuisJanFebMarAprMayJunJulAugSepOctNovDec2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 115:31 AMJun 115:31 AM7:50 PMJun 297:50 PMJun 29Dec 35:33 PMDec 35:33 PM7:41 AMJan 77:41 AMJan 7daynightnightnightnightSolarMidnightSolarMidnightSolarNoonSunriseSunset
The solar day over the course of the year 2017. 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.

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.

San Luis experiences significant seasonal variation in the perceived humidity.

The muggier period of the year lasts for 3.0 months, from June 26 to September 28, during which time the comfort level is muggy, oppressive, or miserable at least 12% of the time. The muggiest day of the year is August 22, with muggy conditions 50% of the time.

The least muggy day of the year is February 26, when muggy conditions are essentially unheard of.

Humidity Comfort Levels

Humidity Comfort Levels in San LuismuggyJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Feb 260%Feb 260%Aug 2250%Aug 2250%Jun 2612%Jun 2612%Sep 2812%Sep 2812%muggymuggydrydryoppressiveoppressivemiserablemiserablecomfortablecomfortable
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 San Luis experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 6.4 months, from November 24 to June 5, with average wind speeds of more than 6.5 miles per hour. The windiest day of the year is April 27, with an average hourly wind speed of 7.2 miles per hour.

The calmer time of year lasts for 5.6 months, from June 5 to November 24. The calmest day of the year is September 26, with an average hourly wind speed of 5.8 miles per hour.

Average Wind Speed

Average Wind Speed in San LuiswindywindyJanFebMarAprMayJunJulAugSepOctNovDec0 mph1 mph2 mph3 mph4 mph5 mph6 mph7 mph8 mph9 mph10 mph11 mph12 mphApr 277.2 mphApr 277.2 mphSep 265.8 mphSep 265.8 mphNov 246.5 mphNov 246.5 mphJun 56.5 mphJun 56.5 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 San Luis varies throughout the year.

The wind is most often from the west for 2.4 months, from March 19 to May 31, with a peak percentage of 44% on April 26. The wind is most often from the south for 3.8 months, from May 31 to September 23, with a peak percentage of 57% on August 4. The wind is most often from the north for 5.9 months, from September 23 to March 19, with a peak percentage of 63% on January 1.

Wind Direction

Wind Direction in San LuisNWSNJanFebMarAprMayJunJulAugSepOctNovDec0%100%20%80%40%60%60%40%80%20%100%0%westsouthnortheast
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).

Water Temperature

San Luis 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 water temperature experiences significant seasonal variation over the course of the year.

The time of year with warmer water lasts for 3.2 months, from July 2 to October 8, with an average temperature above 76°F. The day of the year with the warmest water is August 27, with an average temperature of 80°F.

The time of year with cooler water lasts for 3.6 months, from December 8 to March 27, with an average temperature below 64°F. The day of the year with the coolest water is January 24, with an average temperature of 60°F.

Average Water Temperature

The daily average water temperature (purple line), with 25th to 75th and 10th to 90th percentile bands.

Best Time of Year to Visit

To characterize how pleasant the weather is in San Luis 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 times of year to visit San Luis for general outdoor tourist activities are from late March to mid June and from late September to early November, with a peak score in the third week of October.

Tourism Score

Tourism Score in San Luisbest timebest timeJanFebMarAprMayJunJulAugSepOctNovDec02468107.77.73.23.27.77.74.14.1 precipitationprecipitationcloudscloudstemperaturetemperaturetourism 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 times of year to visit San Luis for hot-weather activities are from late May to mid July and from early September to early October, with a peak score in the third week of June.

Beach/Pool Score

Beach/Pool Score in San Luisbest timeJanFebMarAprMayJunJulAugSepOctNovDec02468107.87.80.40.47.67.66.36.3precipitationprecipitationcloudscloudstemperaturetemperaturebeach/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).

Temperatures in San Luis 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

Time Spent in Various Temperature Bands and the Growing Season in San LuisJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%100%Mar 3100%Mar 393%Jan 1193%Jan 11Jul 21100%Jul 21100%coldcoolwarmhotswelteringcomfortablevery cold
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.

Growing Degree Days

Growing Degree Days in San LuisJanFebMarAprMayJunJulAugSepOctNovDec0°F1,000°F2,000°F3,000°F4,000°F5,000°F6,000°F7,000°F8,000°FJan 1290°FJan 1290°FMar 21900°FMar 21900°FMay 21,800°FMay 21,800°FDec 318,266°FDec 318,266°F
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 3.2 months, from April 18 to July 24, with an average daily incident shortwave energy per square meter above 7.5 kWh. The brightest day of the year is June 10, with an average of 8.6 kWh.

The darker period of the year lasts for 3.1 months, from November 6 to February 8, with an average daily incident shortwave energy per square meter below 4.3 kWh. The darkest day of the year is December 22, with an average of 3.3 kWh.

Average Daily Incident Shortwave Solar Energy

Average Daily Incident Shortwave Solar Energy in San LuisbrightdarkdarkJanFebMarAprMayJunJulAugSepOctNovDec0 kWh1 kWh2 kWh3 kWh4 kWh5 kWh6 kWh7 kWh8 kWh9 kWh10 kWhJun 108.6 kWhJun 108.6 kWhDec 223.3 kWhDec 223.3 kWhApr 187.5 kWhApr 187.5 kWhJul 247.5 kWhJul 247.5 kWhNov 64.3 kWhNov 64.3 kWhFeb 84.3 kWhFeb 84.3 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 San Luis are 32.487 deg latitude, -114.782 deg longitude, and 125 ft elevation.

The topography within 2 miles of San Luis is essentially flat, with a maximum elevation change of 92 feet and an average elevation above sea level of 113 feet. Within 10 miles is essentially flat (233 feet). Within 50 miles contains only modest variations in elevation (3,652 feet).

The area within 2 miles of San Luis is covered by shrubs (49%), cropland (25%), and artificial surfaces (21%), within 10 miles by cropland (45%) and shrubs (44%), and within 50 miles by shrubs (65%) and cropland (18%).

Data Sources

This report illustrates the typical weather in San Luis, 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 2 weather stations near enough to contribute to our estimation of the temperature and dew point in San Luis.

For each station, the records are corrected for the elevation difference between that station and San Luis 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 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 and a given station.

The stations contributing to this reconstruction are: Yuma International Airport (73%, 24 kilometers, northeast) and General Rodolfo Sánchez Taboada International Airport (27%, 46 kilometers, west).

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.