San Jose weather in September
September is one of the best months to visit San Jose: highs of 28°C (83°F) and about 3 mm (0.1 in) of rain on average. Nights average 11°C (51°F) and cloud cover 14% (NASA POWER, 2001–2025 averages). The sea averages 23°C (73°F). It is the 3rd driest month of the year and the 3rd warmest. Compared with August, it is cooler and wetter; October brings highs of 24°C (75°F) and 25 mm (1.0 in) of rain.
Is September a good time to visit San Jose?
best month Weather score 97/100.
Yes. September is one of the best months for weather in San Jose.
Does it rain a lot in San Jose in September?
No, it is usually dry: about 3 mm (0.1 in) falls in an average September. It is the 3rd driest month of the year.
How warm is San Jose in September?
Days average 28°C (83°F) and nights 11°C (51°F).
San Jose weather by month
| Month | High | Low | Rain | Cloud | Sea | Weather |
|---|---|---|---|---|---|---|
| January | 13°C (56°F) | 3°C (38°F) | 88 mm | 54% | 12°C (54°F) | least pleasant |
| February | 14°C (58°F) | 4°C (39°F) | 91 mm | 50% | 13°C (55°F) | least pleasant |
| March | 16°C (61°F) | 5°C (41°F) | 77 mm | 48% | 15°C (59°F) | fair |
| April | 18°C (64°F) | 6°C (42°F) | 41 mm | 41% | 17°C (63°F) | fair |
| May | 21°C (71°F) | 8°C (46°F) | 14 mm | 29% | 20°C (69°F) | best |
| June | 26°C (78°F) | 10°C (49°F) | 4 mm | 16% | 22°C (72°F) | best |
| July | 29°C (83°F) | 11°C (51°F) | 0 mm | 12% | 23°C (74°F) | best |
| August | 29°C (84°F) | 11°C (51°F) | 1 mm | 12% | 23°C (74°F) | best |
| September | 28°C (83°F) | 11°C (51°F) | 3 mm | 14% | 23°C (73°F) | best |
| October | 24°C (75°F) | 9°C (48°F) | 25 mm | 26% | 21°C (70°F) | best |
| November | 18°C (64°F) | 6°C (42°F) | 53 mm | 41% | 17°C (62°F) | fair |
| December | 13°C (56°F) | 4°C (38°F) | 114 mm | 54% | 13°C (56°F) | least pleasant |
Sources: 2001–2025 monthly averages from NASA POWER (MERRA-2 reanalysis), sea temperature from Open-Meteo Marine. Page updated . How we rate months