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Average Weather in Casa Grande Arizona, United States

In Casa Grande, the summers are sweltering, the winters are cold, and it is dry and mostly clear year round. Over the course of the year, the temperature typically varies from 40°F to 105°F and is rarely below 31°F or above 111°F.

Climate Summary

comfortablewarmhotswelteringhotwarmcoolJanFebMarAprMayJunJulAugSepOctNovDec86%86%62%62%clearovercastprecipitation: 1.2 inprecipitation: 1.2 in0.1 in0.1 inmuggy: 17%muggy: 17%0%0%drydrybeach/pool score: 7.3beach/pool score: 7.30.20.2
Click on each chart for more information.

Based on the beach/pool score, the best time of year to visit Casa Grande for hot-weather activities is from early June to late September.

Temperature

The hot season lasts for 3.8 months, from May 26 to September 18, with an average daily high temperature above 97°F. The hottest day of the year is July 1, with an average high of 105°F and low of 76°F.

The cool season lasts for 3.1 months, from November 21 to February 26, with an average daily high temperature below 72°F. The coldest day of the year is January 5, with an average low of 40°F and high of 65°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 Casa GrandeJanFebMarAprMayJunJulAugSepOctNovDec12 AM4 AM8 AM12 PM4 PM8 PM12 AMvery coldcoldcoldcoldcoldcoolcoolwarmhotswelteringhotcomfortablevery coldcomfortable
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.

Tabuk, Saudi Arabia (7,730 miles away); Ha'il, Saudi Arabia (7,923 miles); and Gerāsh, Iran (8,161 miles) are the far-away foreign places with temperatures most similar to Casa Grande (view comparison).

Clouds

In Casa Grande, 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 Casa Grande begins around April 4 and lasts for 3.1 months, ending around July 8. On June 14, the clearest day of the year, the sky is clear, mostly clear, or partly cloudy 86% of the time, and overcast or mostly cloudy 14% of the time.

The cloudier part of the year begins around July 8 and lasts for 8.9 months, ending around April 4. On July 29, the cloudiest day of the year, the sky is overcast or mostly cloudy 38% of the time, and clear, mostly clear, or partly cloudy 62% of the time.

Cloud Cover Categories

Cloud Cover Categories in Casa GrandeclearercloudiercloudierJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%Jun 1486%Jun 1486%Jul 2962%Jul 2962%Apr 474%Apr 474%clearovercastmostly clearpartly cloudymostly 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 Casa Grande varies throughout the year.

The wetter season lasts 2.2 months, from July 7 to September 13, with a greater than 14% chance of a given day being a wet day. The chance of a wet day peaks at 26% on August 4.

The drier season lasts 9.8 months, from September 13 to July 7. The smallest chance of a wet day is 1% on June 9.

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 26% on August 4.

Daily Chance of Precipitation

Daily Chance of Precipitation in Casa GrandewetdrydryJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Aug 426%Aug 426%Jun 91%Jun 91%Jan 111%Jan 111%Jul 714%Jul 714%Sep 1314%Sep 1314%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. Casa Grande experiences some seasonal variation in monthly rainfall.

The rainy period of the year lasts for 9.0 months, from July 2 to April 3, with a sliding 31-day rainfall of at least 0.5 inches. The most rain falls during the 31 days centered around August 13, with an average total accumulation of 1.2 inches.

The rainless period of the year lasts for 3.0 months, from April 3 to July 2. The least rain falls around June 4, with an average total accumulation of 0.1 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 Casa Grande varies significantly over the course of the year. In 2017, the shortest day is December 21, with 9 hours, 59 minutes of daylight; the longest day is June 20, with 14 hours, 19 minutes of daylight.

Hours of Daylight and Twilight

Hours of Daylight and Twilight in Casa GrandeJanFebMarAprMayJunJulAugSepOctNovDec0 hr24 hr4 hr20 hr8 hr16 hr12 hr12 hr16 hr8 hr20 hr4 hr24 hr0 hr12 hr, 7 minMar 2012 hr, 7 minMar 2014 hr, 19 minJun 2014 hr, 19 minJun 2012 hr, 8 minSep 2212 hr, 8 minSep 229 hr, 59 minDec 219 hr, 59 minDec 21nightnightday
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 5:18 AM on June 11, and the latest sunrise is 2 hours, 12 minutes later at 7:30 AM on January 7. The earliest sunset is at 5:20 PM on December 4, and the latest sunset is 2 hours, 19 minutes later at 7:39 PM on June 29.

Daylight saving time (DST) is not observed in Casa Grande during 2017.

Sunrise & Sunset with Twilight

Sunrise & Sunset with Twilight in Casa GrandeJanFebMarAprMayJunJulAugSepOctNovDec2 AM4 AM6 AM8 AM10 AM12 PM2 PM4 PM6 PM8 PM10 PM12 AMJun 115:18 AMJun 115:18 AM7:39 PMJun 297:39 PMJun 29Dec 45:20 PMDec 45:20 PM7:30 AMJan 77:30 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.

Casa Grande experiences some seasonal variation in the perceived humidity.

The muggier period of the year lasts for 2.9 months, from June 29 to September 24, during which time the comfort level is muggy, oppressive, or miserable at least 4% of the time. The muggiest day of the year is August 14, with muggy conditions 17% of the time.

The least muggy day of the year is December 18, when muggy conditions are essentially unheard of.

Humidity Comfort Levels

Humidity Comfort Levels in Casa GrandemuggyJanFebMarAprMayJunJulAugSepOctNovDec0%10%20%30%40%50%60%70%80%90%100%Dec 180%Dec 180%Aug 1417%Aug 1417%Jun 294%Jun 294%Sep 244%Sep 244%muggymuggyhumidhumiddrydrycomfortablecomfortable
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 Casa Grande experiences mild seasonal variation over the course of the year.

The windier part of the year lasts for 8.6 months, from October 23 to July 11, with average wind speeds of more than 6.7 miles per hour. The windiest day of the year is May 6, with an average hourly wind speed of 7.8 miles per hour.

The calmer time of year lasts for 3.4 months, from July 11 to October 23. The calmest day of the year is August 15, with an average hourly wind speed of 5.5 miles per hour.

Average Wind Speed

Average Wind Speed in Casa GrandewindywindyJanFebMarAprMayJunJulAugSepOctNovDec0 mph2 mph4 mph6 mph8 mph10 mph12 mphMay 67.8 mphMay 67.8 mphAug 155.5 mphAug 155.5 mphOct 236.7 mphOct 236.7 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 Casa Grande varies throughout the year.

The wind is most often from the west for 7.6 months, from February 20 to October 7, with a peak percentage of 59% on June 15. The wind is most often from the east for 4.5 months, from October 7 to February 20, with a peak percentage of 48% on January 1.

Wind Direction

Wind Direction in Casa GrandeEWEJanFebMarAprMayJunJulAugSepOctNovDec0%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 Casa Grande 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 Casa Grande for general outdoor tourist activities are from late April to mid June and from mid September to late October, with a peak score in the first week of October.

Tourism Score

Tourism Score in Casa Grandebest timebest timeJanFebMarAprMayJunJulAugSepOctNovDec02468107.37.32.22.27.17.14.84.8precipitationprecipitationcloudscloudstemperaturetemperaturetourism 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 Casa Grande for hot-weather activities is from early June to late September, with a peak score in the second week of September.

Beach/Pool Score

Beach/Pool Score in Casa Grandebest timeJanFebMarAprMayJunJulAugSepOctNovDec02468107.37.30.20.27.27.26.66.6precipitationprecipitationcloudscloudsbeach/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 Casa Grande typically lasts for 10 months (312 days), from around January 31 to around December 9, rarely starting after February 27, or ending before November 19.

Time Spent in Various Temperature Bands and the Growing Season

Time Spent in Various Temperature Bands and the Growing Season in Casa Grandegrowing seasonJanFebMarAprMayJunJulAugSepOctNovDec0%100%10%90%20%80%30%70%40%60%50%50%60%40%70%30%80%20%90%10%100%0%50%Jan 3150%Jan 3150%Dec 950%Dec 990%Feb 2790%Feb 2790%Nov 1990%Nov 1919%Jan 719%Jan 7Jul 18100%Jul 18100%coldcoolwarmhotswelteringvery coldcomfortable
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 Casa Grande should appear around January 19, only rarely appearing before January 13 or after January 25.

Growing Degree Days

Growing Degree Days in Casa GrandeJanFebMarAprMayJunJulAugSepOctNovDec0°F1,000°F2,000°F3,000°F4,000°F5,000°F6,000°F7,000°FJan 1990°FJan 1990°FApr 10900°FApr 10900°FMay 201,800°FMay 201,800°FDec 317,240°FDec 317,240°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 2.8 months, from April 18 to July 13, with an average daily incident shortwave energy per square meter above 7.5 kWh. The brightest day of the year is June 9, with an average of 8.5 kWh.

The darker period of the year lasts for 3.1 months, from November 5 to February 9, with an average daily incident shortwave energy per square meter below 4.3 kWh. The darkest day of the year is December 24, with an average of 3.2 kWh.

Average Daily Incident Shortwave Solar Energy

Average Daily Incident Shortwave Solar Energy in Casa GrandebrightdarkdarkJanFebMarAprMayJunJulAugSepOctNovDec0 kWh1 kWh2 kWh3 kWh4 kWh5 kWh6 kWh7 kWh8 kWh9 kWh10 kWhJun 98.5 kWhJun 98.5 kWhDec 243.2 kWhDec 243.2 kWhApr 187.5 kWhApr 187.5 kWhNov 54.3 kWhNov 54.3 kWhFeb 94.3 kWhFeb 94.3 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 Casa Grande are 32.880 deg latitude, -111.757 deg longitude, and 1,394 ft elevation.

The topography within 2 miles of Casa Grande is essentially flat, with a maximum elevation change of 95 feet and an average elevation above sea level of 1,395 feet. Within 10 miles is essentially flat (1,407 feet). Within 50 miles contains very significant variations in elevation (4,652 feet).

The area within 2 miles of Casa Grande is covered by shrubs (70%), artificial surfaces (16%), and cropland (13%), within 10 miles by shrubs (79%) and cropland (18%), and within 50 miles by shrubs (87%).

Data Sources

This report illustrates the typical weather in Casa Grande, 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 Casa Grande.

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

The stations contributing to this reconstruction are: Casa Grande Municipal Airport (98%, 8 kilometers, north) and Tucson International Airport (1.8%, 112 kilometers, southeast).

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.