Photo: Tony the Marine · CC BY-SA 3.0Casa Grande reaches 100° on about 117 days a year, more than all but 39 U.S. towns
Deep winter brings January lows near 39°. By precipitation alone, it ranks drier than almost every U.S. town. Decade by decade the climate has edged up, 1.9° above 1901–2000. Garden planting can start around February 5; autumn frost returns near December 6.
A year in Casa Grande at a glance
Each month’s typical high and low, and what it brings.
What stands out about Casa Grande’s climate
Compared with towns across the U.S., with Casa Grande’s place in Arizona beside it.
What a year in Casa Grande feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 305 frost-free days a year
In half of years the last 32° night comes by February 5 and the first by December 6. Frost and day counts come from NOAA’s station at Casa Grande, AZ, 3 miles from the city’s center point, at about the same height.
The 2023 USDA map puts Casa Grande’s center in zone 9a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 24°. Plant labels use the zone; frost dates tell you when to plant.
Freezing nights by month
Average nights at or below 32°
90° days by month
Average days at 90° or more
About 8 inches of rain a year
August is the wettest month and June the driest. Rain falls on about 31 days a year. Snow is rare: about 0.0" in a normal year at Casa Grande, AZ, so most winters see none.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Casa Grande
24% of the work is heating, so air conditioning is the bigger bill. Months averaging under 55°: December and January.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Casa Grande, AZ.
Living with Casa Grande’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
305 frost-free days in zone 9a. The last frost comes by Feb 5 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Dec 6.
Months with highs of 62–84° and lows of 40° or more: February, March and November. 231 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in Casa Grande from natural hazards, river flooding is the largest share (70%); heat waves, cold waves, winter storms and ice storms together are 22%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Casa Grande and its neighbors
Every town next door is within a degree of Casa Grande in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Casa Grande’s, farther away
TownRatings’ own comparison of NOAA 1991–2020 normals, not a NOAA product: places of 5,000+ at least 150 miles away, one per state, closest on January low, July high, precipitation and snow.
| Town | Jan. low | July high | Precip. | Snow |
|---|---|---|---|---|
| Casa Grande, AZ | 39° | 106° | 8" | 0.0" |
| Boulder City, NV | 41° | 106° | 4" | 0.0" |
| Garnet, CA | 43° | 105° | 5" | 0.0" |
| St. George, UT | 33° | 103° | 8" | 1.2" |
| Eagle Pass, TX | 41° | 98° | 19" | 0.0" |
Temperatures and rain come from NOAA’s 5 km grid, so each town gets its own value. Snow and frost-free days come from the nearest weather station, so neighbors often share them.
Warmer than it used to be
The last 30 years in Casa Grande averaged 1.9° warmer than the 1900s. The biggest change is in March (+2.8°).
A bigger shift than in 86% of U.S. towns.
Change by month
The two periods overlap (1991–2000 is in both), which makes the gap a little smaller than it would be between separate periods.
How Casa Grande compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Casa Grande’s place among Arizona’s.
Casa Grande weather by month
Highs, lows and precipitation from NOAA’s grid at Casa Grande’s center; snow, wet days and snow on the ground from Casa Grande, AZ. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 68° | 39° | 0.8" | 0.0" | 4 | 0 | 50° – 58° |
| February | 71° | 42° | 0.9" | 0.0" | 4 | 0 | 51° – 61° |
| March | 78° | 47° | 0.8" | 0.0" | 3 | 0 | 54° – 69° |
| April | 86° | 53° | 0.2" | 0.0" | 1 | 0 | 64° – 74° |
| May | 95° | 61° | 0.2" | 0.0" | 1 | 0 | 72° – 84° |
| June | 105° | 70° | 0.1" | 0.0" | 1 | 0 | 82° – 91° |
| July | 106° | 78° | 1.0" | 0.0" | 3 | 0 | 89° – 94° |
| August | 104° | 77° | 1.3" | 0.0" | 5 | 0 | 87° – 95° |
| September | 100° | 71° | 0.7" | 0.0" | 3 | 0 | 81° – 87° |
| October | 89° | 58° | 0.4" | 0.0" | 2 | 0 | 70° – 78° |
| November | 77° | 46° | 0.5" | 0.0" | 2 | 0 | 53° – 67° |
| December | 66° | 38° | 0.8" | 0.0" | 4 | 0 | 49° – 56° |
| Year | 87° | 56° | 7.8" | 0.0" | 31 | 0 |
How much a month can swing
A normal is an average. March swings the most: from 1991 to 2020 its average ranged from 54° to 69°. July is the most reliable, staying within 6°.
Where Casa Grande’s numbers come from
Normals are 30-year averages, not a forecast. How TownRatings reads climate data →
- Temperatures and precipitation: NOAA’s gridded 1991–2020 normals for the 5 km cell at Casa Grande’s center.
- Snow: Casa Grande, AZ.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Casa Grande, AZ, 3 miles from the city’s center point, at about the same height; the nearest station that passes our checks for distance, height and agreement with the grid.
- Growing zone: USDA Plant Hardiness Zone Map, 2023. USDA Agricultural Research Service and PRISM Group, Oregon State University, prism.oregonstate.edu/phzm, accessed 8 Oct 2026.
- Then and now: NOAA’s gridded normals for 1901–2000 at the same cell.
- Storms and extremes: FEMA National Risk Index (expected annual losses to buildings).
Common questions about Casa Grande’s climate
What is the weather like in Casa Grande?
A typical July afternoon reaches 106°, a January night drops to 39°, and snow is almost unheard of. Milder January nights than 87% of U.S. towns; hotter July afternoons than all but 49 U.S. towns.
How cold does it get in Casa Grande in winter?
December nights average 38°. About 17 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 49°.
How much snow does Casa Grande get?
About 0.0 inches in a normal winter at Casa Grande, AZ, so most winters see none.
How hot does it get in Casa Grande?
July, with a typical high of 106° and a low of 78°. About 184 days a year reach 90° and 117 reach 100° (Casa Grande, AZ).
When is the first and last frost in Casa Grande?
In half of years the last spring frost (32°) comes by February 5 and the first fall frost by December 6, about 305 frost-free days, at Casa Grande, AZ.
What growing zone is Casa Grande in?
Zone 9a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 24°.
What is the best time of year to visit Casa Grande?
By one simple rule (highs of 62–84° and lows of 40° or more), February, March and November. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Casa Grande getting warmer?
Yes: 1991–2020 averaged 1.9° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 86% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Casa Grande.
Source: NOAA NCEI U.S. Climate Normals, 1991–2020 and 1901–2000; USDA/PRISM 2023 hardiness zones; FEMA National Risk Index. Today’s forecast: National Weather Service.