San Carlos reaches 100° on about 59 days a year, more than all but 129 U.S. towns
January nights here settle around 32°. Its yearly precipitation falls short of 96% of U.S. towns. The latest 30-year average runs 1.9° warmer than 1901–2000’s, with March up the most. Picnics, hikes and garden evenings suit March, April and October, with highs of 73–84°.
A year in San Carlos at a glance
Each month’s typical high and low, and what it brings.
What stands out about San Carlos’ climate
Compared with towns across the U.S., with San Carlos’ place in Arizona beside it.
What a year in San Carlos feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
About 247 frost-free days a year
In half of years the last 32° night comes by March 13 and the first by November 19. Frost and day counts come from NOAA’s station at San Carlos Reservoir, AZ, 12 miles from the town’s center, 210 ft lower.
The 2023 USDA map puts San Carlos’ center in zone 9a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 23°. 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 12 inches of rain a year
July is the wettest month and June the driest. Rain falls on about 48 days a year. Snow is rare: about 0.0" in a normal year at San Carlos Reservoir, AZ, so most winters see none.
Rain + melted snow by month
Inches of water
Heating and cooling a home in San Carlos
51% of the work is heating. 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 San Carlos Reservoir, AZ.
Living with San Carlos’ climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
247 frost-free days in zone 9a. The last frost comes by Mar 13 in half of years, so many gardeners wait a week or two past that to set out tomatoes. The first fall frost comes by Nov 19.
Months with highs of 62–84° and lows of 40° or more: March, April and October. 13 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in San Carlos from natural hazards, river flooding is the largest share (80%); heat waves, cold waves, winter storms and ice storms together are 7%. Normals are averages; the hazards page covers the extremes.
Natural hazards →San Carlos and similar climates
TownRatings has no climate map of the towns around San Carlos yet.
Climates most like San Carlos’, 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 |
|---|---|---|---|---|
| San Carlos, AZ | 32° | 101° | 12" | 0.0" |
| Ivins, UT | 32° | 100° | 11" | 1.2" |
| Monahans, TX | 30° | 98° | 12" | 0.7" |
| Silver Lakes, CA | 35° | 100° | 4" | 0.0" |
| Summerlin South, NV | 35° | 102° | 5" | 0.2" |
Temperatures and precipitation come from NOAA’s 5 km grid; snow and day counts from the stations named on this page.
Warmer than it used to be
The last 30 years in San Carlos averaged 1.9° warmer than the 1900s. The biggest change is in March (+2.7°).
A bigger shift than in 83% 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 San Carlos compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with San Carlos’ place among Arizona’s.
San Carlos weather by month
Highs, lows and precipitation from NOAA’s grid at San Carlos’ center; snow, wet days and snow on the ground from San Carlos Reservoir, AZ. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 61° | 32° | 1.2" | 0.0" | 5 | 0 | 42° – 52° |
| February | 65° | 36° | 1.2" | 0.0" | 5 | 0 | 45° – 57° |
| March | 73° | 40° | 0.9" | 0.0" | 4 | 0 | 49° – 62° |
| April | 81° | 46° | 0.4" | 0.0" | 2 | 0 | 57° – 69° |
| May | 90° | 53° | 0.3" | 0.0" | 2 | 0 | 65° – 78° |
| June | 100° | 62° | 0.2" | 0.0" | 1 | 0 | 75° – 84° |
| July | 101° | 71° | 2.0" | 0.0" | 6 | 0 | 83° – 89° |
| August | 99° | 70° | 1.9" | 0.0" | 7 | 0 | 82° – 89° |
| September | 94° | 63° | 1.1" | 0.0" | 5 | 0 | 75° – 82° |
| October | 84° | 50° | 0.9" | 0.0" | 3 | 0 | 63° – 72° |
| November | 71° | 38° | 0.9" | 0.0" | 3 | 0 | 48° – 62° |
| December | 60° | 31° | 1.1" | 0.0" | 5 | 0 | 41° – 50° |
| Year | 82° | 49° | 12.1" | 0.0" | 48 | 0 |
How much a month can swing
A normal is an average. November swings the most: from 1991 to 2020 its average ranged from 48° to 62°. July is the most reliable, staying within 6°.
Where San Carlos’ 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 San Carlos’ center.
- Snow: San Carlos Reservoir, AZ.
- Frost, freezing nights, 90° and 100° days, heating and cooling: San Carlos Reservoir, AZ, 12 miles from the town’s center, 210 ft lower; 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 San Carlos’ climate
What is the weather like in San Carlos?
A typical July afternoon reaches 101°, a January night drops to 32°, and snow is almost unheard of. Milder January nights than 75% of U.S. towns; hotter July afternoons than all but 118 U.S. towns.
How cold does it get in San Carlos in winter?
December nights average 31°. About 42 nights a year reach 32° or below. In the coldest December of the last 30 years the month averaged 41°.
How much snow does San Carlos get?
About 0.0 inches in a normal winter at San Carlos Reservoir, AZ, so most winters see none.
How hot does it get in San Carlos?
July, with a typical high of 101° and a low of 71°. About 138 days a year reach 90° and 59 reach 100° (San Carlos Reservoir, AZ).
When is the first and last frost in San Carlos?
In half of years the last spring frost (32°) comes by March 13 and the first fall frost by November 19, about 247 frost-free days, at San Carlos Reservoir, AZ.
What growing zone is San Carlos in?
Zone 9a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 23°.
What is the best time of year to visit San Carlos?
By one simple rule (highs of 62–84° and lows of 40° or more), March, April and October. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is San Carlos getting warmer?
Yes: 1991–2020 averaged 1.9° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 83% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in San Carlos.
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.