Photo: Dirk Hansen · CC BY-SA 3.0San Diego is among the driest of U.S. towns: 11 inches of precipitation a year
The warmest part of a July day comes in at 80° on average. In January, nights here are milder than in 94% of U.S. towns. Compared with 1901–2000, the average now sits 2.2° higher. Garden chairs stay out from January to December, the months with highs of 67–83°.
A year in San Diego at a glance
Each month’s typical high and low, and what it brings.
What stands out about San Diego’s climate
Compared with towns across the U.S., with San Diego’s place in California beside it.
What a year in San Diego feels like
Typical highs and lows by season and by month, from NOAA’s 30-year normals.
Frost is rare
Frost and day counts come from NOAA’s station at San Diego Montgomery Fld, CA, 1.5 miles from the city’s center point, at about the same height.
The 2023 USDA map puts San Diego’s center in zone 10b: the coldest night of a typical winter, averaged over 1991–2020, reaches about 36°. Plant labels use the zone; frost dates tell you when to plant.
90° days by month
Average days at 90° or more
About 11 inches of rain a year
February is the wettest month and August the driest. Rain falls on about 33 days a year. Snow is rare: about 0.0" in a normal year at Chula Vista, CA, so most winters see none.
Rain + melted snow by month
Inches of water
Heating and cooling a home in San Diego
56% of the work is heating. No month averages under 55°.
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 Diego Montgomery Fld, CA.
Living with San Diego’s climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
Zone 10b. Frost comes about 1 winter in 18, so tender plants can often stay out through winter.
Months with highs of 62–84° and lows of 40° or more: January, February, March, April, May, June, July, August, September, October, November and December. 725 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in San Diego from natural hazards, earthquakes are the largest share (49%); heat waves, cold waves, winter storms and ice storms together are 2%. Normals are averages; the hazards page covers the extremes.
Natural hazards →San Diego and its neighbors
Escondido has the coldest January nights next door (42°, 3° colder) and Escondido the hottest July afternoons (87°, 7° warmer). Differences under a degree are within what the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like San Diego’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 |
|---|---|---|---|---|
| San Diego, CA | 45° | 80° | 11" | 0.0" |
| Makawao, HI | 53° | 75° | 23" | 0.0" |
| Sequim, WA | 34° | 71° | 18" | 1.4" |
| The Dalles, OR | 31° | 88° | 15" | 5.5" |
| Alpine, TX | 30° | 90° | 15" | 2.2" |
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 San Diego averaged 2.2° warmer than the 1900s. The biggest change is in January (+3.1°).
A bigger shift than in 96% 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. In a city of 1.4 million, part of the change is the city itself: pavement and buildings hold heat (the urban heat island).
How San Diego compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with San Diego’s place among California’s.
San Diego weather by month
Highs, lows and precipitation from NOAA’s grid at San Diego’s center; snow, wet days and snow on the ground from Chula Vista, CA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 68° | 45° | 2.1" | 0.0" | 5 | 0 | 53° – 62° |
| February | 68° | 46° | 2.5" | 0.0" | 7 | 0 | 53° – 63° |
| March | 69° | 49° | 1.7" | 0.0" | 5 | 0 | 54° – 65° |
| April | 71° | 51° | 0.8" | 0.0" | 3 | 0 | 57° – 66° |
| May | 72° | 56° | 0.3" | 0.0" | 1 | 0 | 60° – 69° |
| June | 76° | 59° | 0.1" | 0.0" | 0 | 0 | 63° – 72° |
| July | 80° | 63° | 0.0" | 0.0" | 0 | 0 | 68° – 77° |
| August | 83° | 64° | 0.0" | 0.0" | 0 | 0 | 70° – 77° |
| September | 82° | 62° | 0.1" | 0.0" | 1 | 0 | 68° – 76° |
| October | 78° | 56° | 0.5" | 0.0" | 1 | 0 | 63° – 72° |
| November | 73° | 49° | 0.9" | 0.0" | 3 | 0 | 55° – 65° |
| December | 67° | 44° | 1.7" | 0.0" | 5 | 0 | 53° – 59° |
| Year | 74° | 54° | 10.7" | 0.0" | 33 | 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 65°. December is the most reliable, staying within 6°.
Where San Diego’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 San Diego’s center.
- Snow: Chula Vista, CA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: San Diego Montgomery Fld, CA, 1.5 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 San Diego’s climate
What is the weather like in San Diego?
A typical July afternoon reaches 80°, a January night drops to 45°, and snow is almost unheard of. Milder January nights than 94% of U.S. towns; cooler July afternoons than 92% of U.S. towns.
How cold does it get in San Diego in winter?
December nights average 44°. A night at 32° or below comes in only some winters (0.2 a year on average). In the coldest December of the last 30 years the month averaged 53°.
How much snow does San Diego get?
About 0.0 inches in a normal winter at Chula Vista, CA, so most winters see none.
How hot does it get in San Diego?
July, with a typical high of 80° and a low of 63°. About 16 days a year reach 90° and 1 reach 100° (San Diego Montgomery Fld, CA).
When is the first and last frost in San Diego?
Most years have no frost at all: a 32° night comes in about 6% of winters at San Diego Montgomery Fld, CA, usually in December or January.
What growing zone is San Diego in?
Zone 10b on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 36°.
What is the best time of year to visit San Diego?
By one simple rule (highs of 62–84° and lows of 40° or more), January, February, March, April, May, June, July, August, September, October, November and December. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is San Diego getting warmer?
Yes: 1991–2020 averaged 2.2° warmer than 1901–2000 on NOAA’s grid. A bigger shift than 96% of U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in San Diego.
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.