What September feels like in San Jose
September falls in San Jose's wet season — the rainfall numbers rise clearly above the dry months. Afternoons are warm and pleasant, good for long days out. Little changes after sunset — nights stay mild, only slightly below the daytime level. High humidity makes the heat feel heavier and sticky, especially on still afternoons.
Rain in San Jose in September
Dry days are the exception, with rain on most days. Rainy days are intense, averaging about 13.8 mm (0.5 in) — downpours rather than drizzle. That is close to San Jose's typical rain per wet day for the whole year (about 12 mm). It is among the three wettest months of the year.
Daylight and sunshine in September
In mid-September, sunrise is at about 5:26 am and sunset at about 5:37 pm (local time) — 12 h 11 min of daylight. Compared with mid-August, the day has lost 16 min. Close to the equator, sunrise and sunset times move very little through the year. Measured sunshine covers about 66% of the daylight — there are plenty of bright spells.
How September compares to the rest of the year
September is the 6th warmest month of the year in San Jose. It is about as warm as August, with 14 mm more rain. Temperatures barely move from one month to the next here. The next month's average high: 23.8°C (74.8°F).
Who September suits
- Sightseeing: less ideal — rain falls on more than half the days.
- Parks & outdoor: less ideal — rain interrupts outdoor plans.
- Museums & indoor: a good choice — with rain on most days, galleries and museums make easy plans.
Tips for visiting San Jose in September
Rain Protection
A compact umbrella and a light waterproof jacket.
Sunglasses
Frequent sunshine — sunglasses and a light hat.
Quick questions
How warm is San Jose in September?
Expect around 24.4°C (75.9°F) in the afternoon and 17.2°C (63°F) at night, which most visitors would call warm.
Does it rain a lot in San Jose in September?
Yes, fairly — rain falls most days and totals about 402 mm, so an umbrella is worth carrying.
What should I wear in San Jose in September?
The numbers point to rain protection and sunglasses. There is little need to change for the evening.
Is September or October better for visiting San Jose?
September scores better on our climate ranking (#10 of 12 vs #12), rated Fair against Fair. October has more rainy days.