Calwa reaches 100° on about 38 days a year, more than 98% of U.S. towns
The coldest hours of a January night bottom out at 39° on average. By precipitation alone, it ranks drier than 98% of U.S. towns. January has warmed most since 1901–2000, part of a 2.1° rise. Long walks are most pleasant from February to April and October to November, when afternoons reach 63–80°.
A year in Calwa at a glance
Each month’s typical high and low, and what it brings.
What stands out about Calwa’s climate
Compared with towns across the U.S., with Calwa’s place in California beside it.
What a year in Calwa feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 38 days a year reach 100°
And 113 days reach 90°. Frost and day counts come from NOAA’s station at Fresno Yosemite International Airport, 5 miles from the town’s center, at about the same height.
The 2023 USDA map puts Calwa’s center in zone 9b: the coldest night of a typical winter, averaged over 1991–2020, reaches about 27°. 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 10 inches of rain a year
January is the wettest month and July the driest. Rain falls on about 47 days a year. Snow is rare: about 0.0" in a normal year at Fresno Yosemite International Airport, so most winters see none.
Rain + melted snow by month
Inches of water
Heating and cooling a home in Calwa
50% of the work is heating, so air conditioning is the bigger bill. Months averaging under 55° run from November through February.
Degree days add up how far each day’s average falls below (heating) or rises above (cooling) 65° over a year. NOAA normals at Fresno Yosemite International Airport.
Living with Calwa’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
Zone 9b. Frost comes about 9 winters in 10, so the growing year is set by heat, not cold: 38 days at 100° make midsummer the hard season for gardens.
Months with highs of 62–84° and lows of 40° or more: February, March, April, October and November.
Parks & trails →Of the yearly building losses FEMA expects in Calwa from natural hazards, earthquakes are the largest share (68%); heat waves, cold waves, winter storms and ice storms together are 2%. Normals are averages; the hazards page covers the extremes.
Natural hazards →Calwa and its neighbors
Every town next door is within a degree of Calwa in January and July, closer than the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like Calwa’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 |
|---|---|---|---|---|
| Calwa, CA | 39° | 98° | 10" | 0.0" |
| Sahuarita, AZ | 37° | 99° | 12" | 0.1" |
| Eagle Pass, TX | 41° | 98° | 19" | 0.0" |
| Ivins, UT | 32° | 100° | 11" | 1.2" |
| Summerlin South, NV | 35° | 102° | 5" | 0.2" |
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 Calwa averaged 2.1° warmer than the 1900s. The biggest change is in January (+2.9°).
A bigger shift than in 94% 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 Calwa compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with Calwa’s place among California’s.
Calwa weather by month
Highs, lows and precipitation from NOAA’s grid at Calwa’s center; snow, wet days and snow on the ground from Fresno Yosemite International Airport. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 56° | 39° | 1.9" | 0.0" | 8 | 0 | 42° – 53° |
| February | 63° | 42° | 1.7" | 0.0" | 9 | 0 | 49° – 57° |
| March | 69° | 45° | 1.6" | 0.0" | 7 | 0 | 50° – 64° |
| April | 75° | 48° | 0.9" | 0.0" | 5 | 0 | 57° – 66° |
| May | 84° | 55° | 0.4" | 0.0" | 3 | 0 | 61° – 77° |
| June | 92° | 61° | 0.1" | 0.0" | 1 | 0 | 71° – 81° |
| July | 98° | 66° | 0.0" | 0.0" | 0 | 0 | 78° – 86° |
| August | 97° | 64° | 0.0" | 0.0" | 0 | 0 | 77° – 84° |
| September | 92° | 60° | 0.1" | 0.0" | 1 | 0 | 72° – 79° |
| October | 80° | 52° | 0.5" | 0.0" | 2 | 0 | 63° – 71° |
| November | 66° | 43° | 0.8" | 0.0" | 5 | 0 | 47° – 59° |
| December | 56° | 38° | 1.6" | 0.0" | 7 | 0 | 43° – 52° |
| Year | 77° | 51° | 9.6" | 0.0" | 47 | 0 |
How much a month can swing
A normal is an average. May swings the most: from 1991 to 2020 its average ranged from 61° to 77°. September is the most reliable, staying within 7°.
Where Calwa’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 Calwa’s center.
- Snow: Fresno Yosemite International Airport.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Fresno Yosemite International Airport, 5 miles from the town’s center, 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 Calwa’s climate
What is the weather like in Calwa?
A typical July afternoon reaches 98°, a January night drops to 39°, and snow is almost unheard of. Milder January nights than 88% of U.S. towns; hotter July afternoons than all but 187 U.S. towns.
How cold does it get in Calwa in winter?
December nights average 38°. About 11 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 43°.
How much snow does Calwa get?
About 0.0 inches in a normal winter at Fresno Yosemite International Airport, so most winters see none.
How hot does it get in Calwa?
July, with a typical high of 98° and a low of 66°. About 113 days a year reach 90° and 38 reach 100° (Fresno Yosemite International Airport).
When is the first and last frost in Calwa?
There is no reliable frost date: a 32° night comes in about 85% of winters at Fresno Yosemite International Airport, so most years bring a freeze but some pass without one.
What growing zone is Calwa in?
Zone 9b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 27°.
What is the best time of year to visit Calwa?
By one simple rule (highs of 62–84° and lows of 40° or more), February, March, April, October and November. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is Calwa getting warmer?
Yes: 1991–2020 averaged 2.1° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 94% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in Calwa.
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.