September weather forecast
San Jose, CA

A sunset panorama of the lit city of San Jose, California
A sunset panorama of the lit city of San Jose, California

Weather in September

September, the first month of the autumn in San Jose, is still a warm month, with temperature in the range of an average low of 55.6°F (13.1°C) and an average high of 79.7°F (26.5°C).

Temperature

In September, the average high-temperature is relatively the same as in August - a still warm 79.7°F (26.5°C). In San Jose, California, in September, the average low-temperature is 55.6°F (13.1°C).

Humidity

July and September, with an average relative humidity of 60%, are the least humid months.

Rainfall

In September, in San Jose, the rain falls for 2.1 days. Throughout September, 0.08" (2mm) of precipitation is accumulated. In San Jose, during the entire year, the rain falls for 51.5 days and collects up to 4.06" (103mm) of precipitation.

Daylight

In September, the average length of the day in San Jose, California, is 12h and 25min.
On the first day of September, sunrise is at 6:38 am and sunset at 7:36 pm. On the last day of the month, sunrise is at 7:02 am and sunset at 6:52 pm PDT.

Sunshine

The average sunshine in September is 11.2h.

UV index

In San Jose, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV radiation for the average person.
Note: In September, the average maximum UV index of 5 translate into the following recommendations:
Take precautions. Light skin individuals may get burned in less than 30 minutes. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun.
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FAQ

What is the temperature in September in San Jose?

In September, in San Jose, California, the average high-temperature is 79.7°F (26.5°C), and the average low-temperature is 55.6°F (13.1°C). The average heat index (a.k.a. 'apparent temperature', 'real feel'), which combines air temperature and relative humidity, in August is calculated to be 84.2°F (29°C).

What is the least humid month in San Jose?

July and September, with an average relative humidity of 60%, are the least humid months.

What is the average humidity in September in San Jose?

The average relative humidity in September in San Jose is 60%.

How many days does it rain in September in San Jose?

In San Jose, California, during September, the rain falls for 2.1 days and regularly aggregates up to 0.08" (2mm) of precipitation.

What is the average length of the day in September in San Jose?

The average day length in September is 12h and 25min.

When are sunrise and sunset in September in San Jose?

In September, on the first day of the month, sunrise is at 6:38 am and sunset at 7:36 pm. On the last day of the month, in San Jose, California, sunrise is at 7:02 am and sunset at 6:52 pm PDT.

How long on average sun shines in September in San Jose?

In San Jose, California, the average sunshine duration in September is 11.2h.

What is the UV index intensity in September in San Jose?

In September, the average daily maximum UV index is 5. A UV Index estimate of 3 to 5 represents a moderate vulnerability from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
San Jose, CA

Average temperature in September - San Jose, CA
  • Average high temperature in September: 79.7°F

The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is December (56.5°F).

  • Average low temperature in September: 55.6°F

The month with the highest average low temperature is August (56.5°F).
The coldest month (with the lowest average low temperature) is December (43°F).

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Average pressure in September
San Jose, CA

Average pressure in September - San Jose, CA
  • Average pressure in September: 29.92"Hg

The month with the highest atmospheric pressure is January (30.13"Hg).
The months with the lowest atmospheric pressure are June, August and September (29.92"Hg).

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Average wind speed in September
San Jose, CA

Average wind speed in September - San Jose, CA
  • Average wind speed in September: 4.4mph

The windiest months (with the highest average wind speed) are April and May (5.8mph).
The calmest months (with the lowest average wind speed) are September and October (4.4mph).

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Average humidity in September
San Jose, CA

Average humidity in September - San Jose, CA
  • Average humidity in September: 60%

The month with the highest relative humidity is March (73%).
The months with the lowest relative humidity are July and September (60%).

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Average rainfall in September
San Jose, CA

Average rainfall in September - San Jose, CA
  • Average rainfall in September: 0.08"

The wettest month (with the highest rainfall) is March (0.83").
The driest months (with the least rainfall) are June, July and August (0.04").

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Average rainfall days in September
San Jose, CA

Average rainfall days in September - San Jose, CA
  • Average rainfall days in September: 2.1 days

The month with the highest number of rainy days is March (9.8 days).
The month with the least rainy days is August (0.4 days).

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Average daylight in September /
Average sunshine in September
San Jose, CA

Average daylight in September / Average sunshine in September - San Jose, CA
  • Average daylight in September: 12h and 25min

The month with the longest days is June (Average daylight: 14h and 41min).
The month with the shortest days is December (Average daylight: 9h and 38min).

  • Average sunshine in September: 11h and 12min

The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 6h and 0min).

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Average sunshine days in September
San Jose, CA

Average sunshine days in September - San Jose, CA
  • Average sunshine days in September: 26.8 days

The month with the most sunshine days is August (29.7 days).
The month with the least sunshine days is March (19.5 days).

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Average UV index in September
San Jose, CA

Average UV index in September - San Jose, CA
  • Average UV index in September: 5

The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).

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Average cloud cover in September
San Jose, CA

Average cloud cover in September - San Jose, CA
  • Average cloud cover in September: 10

The month with the most cloud cover is March (Cloud cover 35).
The month with the least cloud cover is July (Cloud cover 6).

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Average visibility in September
San Jose, CA

Average visibility in September - San Jose, CA
  • Average visibility in September: 6mi

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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