Weather in San Jose in September 2025
Average weather
Average temperature in San Jose in September
The expected average maximum temperature in September is +79°F with a maximum of +82°F and a minimum of +64°F.
The average maximum temperature goes up 20% by the end of the month, compared with the beginning of the month, from +79°F to +82°F.
Is San Jose warm or cold in September?
San Jose is typically warm in September.
Maximum temperatures go up compared to the previous month from +75°F to +75°F. The minimum temperature also goes down from +64°F to +63°F.
It’s generally warm, but pack a long-sleeve shirt for evenings.
Take a look at how September is compared to other months in San Jose:
Water temperature in San Jose in September
Water in San Jose in September is Very warm. It varies from +82°F to +86°F, with an average of +84°F. Note that the air temperature is lower than the water temperature, averaging around +75°F.
In September, water temperatures are average relative to the rest of the year:
Can you swim in San Jose in September?
Climate in San Jose in September
| August | September | October | ||||
|---|---|---|---|---|---|---|
| Avg. temperature | ||||||
| +75°F | +75°F | +75°F | ||||
| Min. temperature | ||||||
| +59°F | +57°F | +57°F | ||||
| Max. temperature | ||||||
| +84°F | +84°F | +84°F | ||||
| Rainfall | ||||||
| 753 mm | 670 mm | 684 mm | ||||
| Wind | ||||||
| 2 m/s | 2 m/s | 2 m/s | ||||
| Avg. water temperature | ||||||
| +84°F | +84°F | +82°F | ||||
| Humidity | ||||||
| 82% | 85% | 85% | ||||
| Air pressure | ||||||
| 1014 HPa | 1014 HPa | 1014 HPa | ||||
| Sunny days | ||||||
| 0 | 0 | 0 | ||||
| Cloudy days | ||||||
| 0 | 0 | 0 | ||||
| Rainy days | ||||||
| 19 | 16 | 21 | ||||
| Snowy days | ||||||
| 0 | 0 | 0 | ||||
September weather is still as ok as in August. The temperature levels stay the same in the area of +75°F for average maximum temperature during the day. As September arrives, the amount of rainfall goes down. On average, the rainfall volume decreases from 753 mm to 670 mm. Humidity rises from 82% to 85%. The average wind speed doesn’t change much during September, staying around 2 m/s. The amount of sunny days stay about the same, averaging 0 sunny days during the month.
October brings much the same weather, it remains ok.
Wind
The average wind speed is 3 m/s getting up to 5 m/s which is a light breeze; barely moving the tree leaves.
The average wind speed in San Jose is gradually increasing during September, going from 3 m/s to 3 m/s over the course of the month.
Rain
How was the weather last September in San Jose?
Climate Change Over the Years
The climate in San Jose in September has not changed that much over the last 43 years.
The average temperature was the lowest in 1999 (+74°F) and the highest in 2013 (+79°F). The driest year was 2023 with only 3365 mm of rainfall, and the wettest year was 1995 with 7044 mm.
FAQ
Is September a good time to visit San Jose?
Can you sunbathe in San Jose in September?
Can you swim in San Jose in September?
Is San Jose rainy in September?
Is it sunny in San Jose in September?
Monthly weather in San Jose
Source of the data
For this page, we’ve looked at the typical weather in San Jose, based on historical hourly weather data from January 1, 1979, to December 31, 2023.
For past dates, we show actual recorded data at the location at that time. Forecasts are based on recorded weather during that day of the year, averaged over the total years for which we have records (unless stated otherwise). The daily temperature is the highest recorded temperature in the shadow during that day.