San Jose climate: monthly averages: annual mean temperature 14.0 C; warmest month Aug (19.8 C); coldest month Jan (8.3 C).
Annual mean temperature: 14.0 C
Warmest month: Aug (19.8 C)
Coldest month: Jan (8.3 C)
Wettest month: Dec (3.68 mm/day)
All-time record high: 45.3 C
All-time record low: -5.1 C
One page for San Jose climate: monthly averages, sourced from public APIs and refreshed automatically. Expect 8.3 C at the coldest (Jan) and 19.8 C at the warmest (Aug) — a 11.5 C spread. Expect a wet season rather than rain year-round: Dec brings 3.68 mm/day against 0.01 mm/day in Jul. Taken together that is roughly 513 mm of rain a year for the grid cell. The build runs on a schedule and caches the last good response, so the numbers stay put even when the upstream API is having a bad day. Exact monthly values are in the table; links below cover adjacent locations and years.
Annual mean temperature 14.0 C
Warmest month Aug (19.8 C)
Coldest month Jan (8.3 C)
Wettest month Dec (3.68 mm/day)
All-time record high 45.3 C
All-time record low -5.1 C
Annual precipitation 511 mm / year
Coordinates 37.33939, -121.89496
Population 997,368
Average monthly temperature and rainfall in San Jose
Month
Mean temp (C)
Rain (mm/day)
Record high (C)
Record low (C)
Jan
8.3
2.84
23.1
-5.1
Feb
9.2
3.22
24.1
-3.3
Mar
10.7
2.48
28.5
-1.3
Apr
11.9
1.35
33.2
0.5
May
14.5
0.46
38.0
3.6
Jun
17.6
0.13
40.5
5.8
Jul
19.6
0.01
45.3
7.8
Aug
19.8
0.02
42.8
8.1
Sep
19.4
0.10
44.8
6.9
Oct
16.3
0.82
39.3
2.1
Nov
11.7
1.77
32.1
-3.0
Dec
8.4
3.68
21.0
-4.8
What the San Jose climate table shows
Values are multi-decadal climatological averages for the 37.33939, -121.89496 grid cell, not a single year. Rain is the daily mean, so a value of 2.00 mm/day is about 60 mm across a 30-day month. Averages smooth over extremes, so use them for planning rather than for what to pack for next Tuesday.
Frequently asked questions
Is San climate data a forecast?
No. These are multi-decadal averages for the grid cell, not a prediction for any particular year.
Why do the numbers differ from a weather app?
An app shows one location on one day. These are long-run averages, so they smooth out single hot or cold spells.