Photo: Joe Mabel · CC BY-SA 4.0Nights stay kind in South San Jose Hills each January, milder than in 94% of U.S. towns
Expect July afternoons of about 88°. Rain follows the seasons: February brings about 378 times as much as August. It is a dry place: less rain and snow fall here than on 93% of U.S. towns. Picnics, hikes and garden evenings come into their own from October to June, with highs of 68–83°.
A year in South San Jose Hills at a glance
Each month’s typical high and low, and what it brings.
What stands out about South San Jose Hills’ climate
Compared with towns across the U.S., with South San Jose Hills’ place in California beside it.
What a year in South San Jose Hills 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 Fullerton Muni Airport, 11 miles from the town’s center, 340 ft lower.
The 2023 USDA map puts South San Jose Hills’ center in zone 10a: the coldest night of a typical winter, averaged over 1991–2020, reaches about 34°. Plant labels use the zone; frost dates tell you when to plant.
90° days by month
Average days at 90° or more
About 15 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 Covina City Yard Fc387b, CA, so most winters see none.
Rain + melted snow by month
Inches of water
Heating and cooling a home in South San Jose Hills
41% of the work is heating, so air conditioning is the bigger bill. 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 Fullerton Muni Airport.
Living with South San Jose Hills’ climate
What the numbers mean for a garden, a free afternoon and a bad-weather day.
Zone 10a. Frost comes about 1 winter in 14, 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, October, November and December. 0.5 miles of trails are waiting.
Parks & trails →Of the yearly building losses FEMA expects in South San Jose Hills from natural hazards, earthquakes are the largest share (58%); heat waves, cold waves, winter storms and ice storms together are 1%. Normals are averages; the hazards page covers the extremes.
Natural hazards →South San Jose Hills and its neighbors
West Covina has the coldest January nights next door (45°, 1° colder). Differences under a degree are within what the 5 km grid can tell apart. Tap a town to see its climate.
Climates most like South San Jose Hills’, 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 |
|---|---|---|---|---|
| South San Jose Hills, CA | 46° | 88° | 15" | 0.0" |
| Port Isabel, TX | 52° | 92° | 26" | 0.2" |
| Sierra Vista Southeast, AZ | 32° | 91° | 15" | 0.7" |
| Ewa Beach, HI | 62° | 87° | 17" | 0.0" |
| Ashland, OR | 31° | 91° | 19" | 0.5" |
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 South San Jose Hills averaged 2.6° warmer than the 1900s. The biggest change is in January (+3.6°).
A bigger shift than in all but 29 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 South San Jose Hills compares
Against 12,954 U.S. towns of 2,500 or more (one per 5 km climate cell), with South San Jose Hills’ place among California’s.
South San Jose Hills weather by month
Highs, lows and precipitation from NOAA’s grid at South San Jose Hills’ center; snow, wet days and snow on the ground from Covina City Yard Fc387b, CA. 1991–2020 normals.
| Month | High | Low | Rain + melt | Snow | Wet days | Snow on ground | 30-yr range |
|---|---|---|---|---|---|---|---|
| January | 69° | 46° | 3.5" | 0.0" | 6 | 0 | 53° – 63° |
| February | 69° | 47° | 3.8" | 0.0" | 6 | 0 | 51° – 67° |
| March | 71° | 49° | 2.2" | 0.0" | 5 | 0 | 54° – 67° |
| April | 75° | 51° | 0.8" | 0.0" | 3 | 0 | 58° – 67° |
| May | 77° | 55° | 0.3" | 0.0" | 2 | 0 | 62° – 73° |
| June | 83° | 59° | 0.1" | 0.0" | 1 | 0 | 67° – 75° |
| July | 88° | 63° | 0.0" | 0.0" | 0 | 0 | 72° – 81° |
| August | 90° | 64° | 0.0" | 0.0" | 0 | 0 | 74° – 81° |
| September | 88° | 62° | 0.1" | 0.0" | 0 | 0 | 71° – 79° |
| October | 82° | 57° | 0.5" | 0.0" | 2 | 0 | 64° – 74° |
| November | 74° | 50° | 0.8" | 0.0" | 3 | 0 | 55° – 66° |
| December | 68° | 45° | 2.3" | 0.0" | 5 | 0 | 53° – 61° |
| Year | 78° | 54° | 14.5" | 0.0" | 33 | 0 |
How much a month can swing
A normal is an average. February swings the most: from 1991 to 2020 its average ranged from 51° to 67°. August is the most reliable, staying within 7°.
Where South San Jose Hills’ 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 South San Jose Hills’ center.
- Snow: Covina City Yard Fc387b, CA.
- Frost, freezing nights, 90° and 100° days, heating and cooling: Fullerton Muni Airport, 11 miles from the town’s center, 340 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 South San Jose Hills’ climate
What is the weather like in South San Jose Hills?
A typical July afternoon reaches 88°, a January night drops to 46°, and snow is almost unheard of. Milder January nights than 94% of U.S. towns; hotter July afternoons than 69% of U.S. towns.
How cold does it get in South San Jose Hills in winter?
December nights average 45°. A night at 32° or below comes in only some winters (0.3 a year on average). In the coldest December of the last 30 years the month averaged 53°.
How much snow does South San Jose Hills get?
About 0.0 inches in a normal winter at Covina City Yard Fc387b, CA, so most winters see none.
How hot does it get in South San Jose Hills?
July, with a typical high of 88° and a low of 63°. About 39 days a year reach 90° and 4 reach 100° (Fullerton Muni Airport).
When is the first and last frost in South San Jose Hills?
Most years have no frost at all: a 32° night comes in about 7% of winters at Fullerton Muni Airport, usually in December or January.
What growing zone is South San Jose Hills in?
Zone 10a on the 2023 USDA Plant Hardiness Zone Map: the coldest night of a typical winter reaches about 34°.
What is the best time of year to visit South San Jose Hills?
By one simple rule (highs of 62–84° and lows of 40° or more), January, February, March, April, May, June, October, November and December. The rule is ours, not NOAA’s; the month table has the numbers to judge by.
Is South San Jose Hills getting warmer?
Yes: 1991–2020 averaged 2.6° warmer than 1901–2000 on NOAA’s grid. A bigger shift than all but 29 U.S. towns.
Neighbors talk weather
Gardens, snow, and the best days of the year in South San Jose Hills.
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.