Casa Grande, Arizona climate: Normal weather by month, frost dates and records
Casa Grande's normal year runs from 38°F December nights to 107°F July afternoons, with 7.9 inches of precipitation a year. (NOAA 1991-2020 normals)
In metric: a yearly mean of 22.4°C, December lows of 4°C, July highs of 42°C, 201 mm of precipitation a year.
- NOAA stationCasa Grande
- Station IDUSC00021306
- Location32.89°N 111.71°W
- Elevation1,400 ft (427 m)
- From the center3 miles
- Population68,927
On October 23, the normal high in Casa Grande is 88°F and the normal low 54°F, and the chance of measurable rain or snow is 7%.
Normals describe a typical year at the station, not a forecast. The National Weather Service forecast for Casa Grande.
- Jan 69° 39°
- Feb 73° 42°
- Mar 80° 47°
- Apr 88° 53°
- May 96° 60°
- Jun 106° 70°
- Jul 107° 78°
- Aug 105° 77°
- Sep 100° 71°
- Oct 91° 57°
- Nov 78° 45°
- Dec 68° 38°
Each month: normal high (large) and low, °F. Fill: the month's normal mean, colder blue to hotter red.
What is the weather like in Casa Grande each month?
July is the warmest month, with normal highs of 107°F; December the coldest, with normal lows of 38°F. The most precipitation falls in August (1.52 in), the least in May (0.18 in).
Each month has its own page with the day-by-day normals, the month's records and its recent years:
| Month | High | Low | Mean | Precip. | Wet days | 90°F days | Freezing nights | Daylight |
|---|---|---|---|---|---|---|---|---|
| January | 69°F | 39°F | 53.9°F | 0.79 | 4 | <1 | 5 | 10 h 10 min |
| February | 73°F | 42°F | 57.0°F | 1.00 | 4 | <1 | 2 | 11 h |
| March | 80°F | 47°F | 63.6°F | 0.76 | 3 | 3 | <1 | 12 h |
| April | 88°F | 53°F | 70.3°F | 0.21 | 1 | 12 | <1 | 13 h |
| May | 96°F | 60°F | 78.4°F | 0.18 | 1 | 26 | <1 | 13 h 50 min |
| June | 106°F | 70°F | 87.9°F | 0.18 | 1 | 30 | <1 | 14 h 20 min |
| July | 107°F | 78°F | 92.5°F | 0.91 | 3 | 31 | <1 | 14 h 10 min |
| August | 105°F | 77°F | 91.3°F | 1.52 | 5 | 31 | <1 | 13 h 20 min |
| September | 100°F | 71°F | 85.5°F | 0.72 | 3 | 30 | <1 | 12 h 30 min |
| October | 91°F | 57°F | 73.8°F | 0.48 | 2 | 19 | <1 | 11 h 30 min |
| November | 78°F | 45°F | 61.4°F | 0.43 | 2 | 2 | 2 | 10 h 30 min |
| December | 68°F | 38°F | 53.0°F | 0.73 | 4 | <1 | 7 | 10 h |
| Year (annual) | 88°F | 57°F | 72.4°F | 7.91 | 31 | 184 | 17 |
The same normals in °C and millimetres
| Month | High | Low | Mean | Precip. |
|---|---|---|---|---|
| January | 20°C | 4°C | 12.2°C | 20 mm |
| February | 23°C | 5°C | 13.9°C | 25 mm |
| March | 27°C | 8°C | 17.6°C | 19 mm |
| April | 31°C | 12°C | 21.3°C | 5 mm |
| May | 36°C | 16°C | 25.8°C | 5 mm |
| June | 41°C | 21°C | 31.1°C | 5 mm |
| July | 42°C | 26°C | 33.6°C | 23 mm |
| August | 41°C | 25°C | 32.9°C | 39 mm |
| September | 38°C | 22°C | 29.7°C | 18 mm |
| October | 33°C | 14°C | 23.2°C | 12 mm |
| November | 25°C | 7°C | 16.3°C | 11 mm |
| December | 20°C | 4°C | 11.7°C | 19 mm |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00021306; annual normals. Wet days: 0.01 inch or more; 90°F days and freezing nights: NOAA's day counts. Daylight: sunrise to sunset on the 15th, computed from the latitude.
When is the best weather to visit Casa Grande?
Normal highs sit between 65°F and 85°F in January, February, March, November and December. Of those, November has the fewest days with rain (2).
That is a measurement, not a recommendation: it counts the months whose normal afternoon high sits between 65°F and 85°F, where a light layer is enough by day.
Source: NOAA NCEI 1991-2020 monthly normals, station USC00021306.
When is the last frost in Casa Grande?
In Casa Grande, the last spring frost (32°F) comes after February 5 in half of years and after February 28 in one year in ten; the first autumn frost comes before December 6 in half of years and before November 18 in one year in ten.
Frost-free in half of yearsFrost in 1 to 9 years out of 10Frost most years
- Last spring frost, half of years after
- February 51 year in 10 after February 28; 9 in 10 after January 5
- First autumn frost, half of years before
- December 61 year in 10 before November 18; 9 in 10 before December 29
NOAA puts the median frost-free season at 305 days, and the season without a hard freeze (28°F) at 340 days.
A hard freeze (28°F) comes after January 14 in half of springs and before December 22 in half of autumns.
The USDA's 2023 Plant Hardiness Zone Map puts Casa Grande in zone 9a across its 3 ZIP code areas (9a in 85122, the largest).
Frost dates for every NOAA station in Arizona · Frost dates by ZIP code
Source: NOAA NCEI 1991-2020 annual normals (frost probabilities), station USC00021306; USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026. A 10% date means one year in ten has a frost after it in spring or before it in autumn.
What hardiness zone is each Casa Grande ZIP code in?
The USDA's 2023 map gives each ZIP code area one zone. Casa Grande's 3 ZIP code areas are all in zone 9a. Each ZIP's frost dates are in the frost tool.
Source: USDA 2023 Plant Hardiness Zone Map, ZIP listings: PRISM Group, Oregon State University, https://prism.oregonstate.edu, accessed October 8, 2026; ZIP areas in the place: Census Bureau 2020 ZCTA-to-place relationship file. A ZIP area counts when at least a tenth of its land (and 0.5 km²) lies in the place.
How hot and how cold does it get in Casa Grande?
In a normal year in Casa Grande, 184 days a year reach 90°F (117 of them 100°F or more), 17 nights fall to 32°F or colder and 31 days bring measurable precipitation.
- Days at 90°F or more
- 184a normal year
- Days at 100°F or more
- 117a normal year
- Nights at 32°F or colder
- 17a normal year
- Days that stay below freezing
- fewer than 1high of 32°F or less
- Days with 0.01 inch of precipitation
- 31a normal year
The highest temperature in this station's record (since 1903) is 122°F, on July 6, 1905; the lowest is 15°F, on December 28, 1954.
The wettest calendar year on that record is 1905, with 19.52 in.
Source: NOAA NCEI 1991-2020 annual normals, station USC00021306; records: ACIS (NOAA Regional Climate Centers), station USC00021306. Records use complete months only; a month missing more than three days is left out.
How sunny is Casa Grande?
Over a year 92% of the sunlight that would reach the ground under clear skies gets through the clouds in the area around Casa Grande, 5.9 kWh per square metre a day. June is the sunniest month (96%) and December the cloudiest (86%). Among the 459 U.S. places of 50,000 or more, that ranks tied 3rd (with 7 others) in sunshine.
| Month | Share of clear-sky sunshine | Sunshine, kWh/m² a day |
|---|---|---|
| January | 87% | 3.6 |
| February | 87% | 4.6 |
| March | 91% | 6.0 |
| April | 94% | 7.4 |
| May | 95% | 8.2 |
| June | 96% | 8.4 |
| July | 88% | 7.2 |
| August | 90% | 6.7 |
| September | 92% | 6.1 |
| October | 94% | 5.1 |
| November | 91% | 3.9 |
| December | 86% | 3.3 |
Source: NASA POWER solar climatology, 2001-2020 (CERES SYN1deg). Satellite-based, for the 1-degree cell (about 100 km across) around the station, so it describes the area rather than the airport.
How much heating and cooling does Casa Grande need?
A normal year in Casa Grande brings 1,241 heating degree days, 77% fewer than the median U.S. place (5,373), and 3,963 cooling degree days, 4.4 times the median (908). Two months need 300 or more heating degree days, a monthly mean of about 55°F or colder. For gardens and crops, NOAA counts 8,266 growing degree days a year above 50°F.
| Month | Heating | Cooling |
|---|---|---|
| January | 345 | 1 |
| February | 229 | 6 |
| March | 105 | 60 |
| April | 23 | 181 |
| May | 2 | 418 |
| June | 0 | 685 |
| July | 0 | 851 |
| August | 0 | 815 |
| September | 0 | 617 |
| October | 12 | 285 |
| November | 151 | 43 |
| December | 372 | 1 |
| Year (annual) | 1,241 | 3,963 |
Source: NOAA NCEI 1991-2020 monthly normals, station USC00021306. A degree day is one degree of a day's mean temperature below 65°F (heating) or above it (cooling); utilities use them to estimate energy use.
How does Casa Grande's climate compare?
Casa Grande is warmer than 81 of the other 96 places with their own NOAA record in Arizona, and wetter than 20. Across the 7,247 U.S. stations with normals, its annual mean of 72.4°F is warmer than 97%.
In the Köppen classification computed from these normals, Casa Grande is BWh: hot desert. What the classes mean.
Places with the most similar year elsewhere
Measured month by month on the normal high, low and precipitation, among places of 20,000 or more people in other states:
Source: NOAA NCEI 1991-2020 normals for every station PlainClimate covers. Similarity: the root-mean-square difference of the 36 monthly figures, precipitation weighted so an inch counts like 6°F.
Which places near Casa Grande share this climate record?
Stanfield has no NOAA station with 1991-2020 normals of its own, and this station is the nearest full record. A place's own climate can differ from these figures, by several degrees where it sits much higher or lower than the station, nearer the coast, or inside a large city's heat; for the larger places the next nearest records are named with their yearly mean, so the spread around them is visible, and places of 50,000 or more have their own page with NOAA's gridded normals.
- Stanfield, AZ338 people · 14 mi W
Source: Census Bureau 2024 Gazetteer (place centers) and Vintage 2024 population estimates. Distance and direction from the station to each place's center.
Questions about Casa Grande's climate
What is the coldest month in Casa Grande?
December, with a normal high of 68°F and a normal low of 38°F. The warmest is July (107°F by day, 78°F at night).
Does it snow in Casa Grande?
Rarely: NOAA's normal is no measurable snow a year.
What is the rainiest month in Casa Grande?
August, with 1.52 in of precipitation in a normal year; the driest is May with 0.18 in.
What plant hardiness zone is Casa Grande in?
The USDA's 2023 map puts Casa Grande in zone 9a across its 3 ZIP code areas (9a in 85122, the largest).
How late can frost come in Casa Grande?
In half of years the last 32°F night comes after February 5; in one year in ten it comes after February 28. Waiting until February 28 leaves about a one-in-ten chance of a later frost.
Nearby and next
- Casa Grande in OctoberThis month day by day, its records and recent years
- Arizona climateThe statewide normals and every place in the state
- Robson Ranch, AZ7 miles from this station, 71.3°F a year
- Arizona City, AZ11 miles from this station, 68.9°F a year
- Coolidge, AZ12 miles from this station, 71.3°F a year
- Eloy, AZ14 miles from this station, 70.9°F a year
- Compare two placesMonth by month, side by side
Download these normals (CSV) · JSON · How these figures are made