San Jose weather in September
Long-run climate averages for San Jose, CA in September, plus what the forecast models say for the days ahead.
In September, San Jose averages 83°F by day and 59°F at night. The wettest month is usually January.
September in San Jose averages a daytime high of 83°F and an overnight low of 59°F, which reads as warm for this part of the world. It is among the three warmest months of the year here. Across the whole year San Jose sees roughly 22 inches of precipitation.
Climate averages tell you what to pack. They do not tell you what next Tuesday looks like - for that, see the live San Jose forecast with every model compared and how much they currently agree.
San Jose weather by month
what to expect in San Jose through the year, 1991-2020 averagesHere is San Jose's typical weather in each month: the average daytime high and overnight low in °F, how each month feels, and the wettest month marked. Use it to plan any trip to San Jose by season.
Bottom line: over the last 30 days the American model has been the most accurate forecast for San Jose, scoring 88/100 on our CheckWeather Score, ahead of the European at 84. See the full US accuracy scoreboard for exactly how every model is tested.
Common questions
How warm is San Jose in September?
Is September a good time to visit San Jose?
Does it rain a lot in San Jose in September?
Climate averages from ERA5 reanalysis. Model accuracy re-scored over a rolling 30 days. Page updated .