September weather forecast
Santa Clara, CA

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Weather in September

September signifies the onset of fall in Santa Clara, with the average temperatures dipping slightly from the summer highs. However, the sun continues to shine generously upon the city, making it a suitable period for outdoor undertakings. This time of year is marked by a decline in daylight hours, signaling the approaching fall. As the seasons shift, the city's beauty is amplified by its colorful foliage and clear blue skies. The weather conditions during September in Santa Clara, California transition seamlessly to usher in the beautiful fall season.

Temperature

Santa Clara marks the start of September with an average high-temperature of a still warm 79.2°F (26.2°C), hinting at a slight fluctuation from August's 81.3°F (27.4°C). In Santa Clara, the nighttime temperature registers a significant drop from daytime peaks to an average of 55.6°F (13.1°C) in September.

Humidity

July and September, with an average relative humidity of 61%, are the least humid months.

Rainfall

In Santa Clara, during September, the rain falls for 2.7 days and regularly aggregates up to 0.12" (3mm) of precipitation. Throughout the year, there are 70.2 rainfall days, and 9.8" (249mm) of precipitation is accumulated.

Daylight

The average length of the day in September is 12h and 25min.
On the first day of September, sunrise is at 6:39 am and sunset at 7:36 pm. On the last day of the month, sunrise is at 7:03 am and sunset at 6:51 pm PDT.

Sunshine

The average sunshine in September is 11.1h.

UV index

The average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a medium health hazard from unsafe exposure to UV radiation for the average person.
Note: During September, 5 as the daily maximum UV index converts into the following advice:
Undertake protective steps - Recommendations to avoid sunburn are issued. Given the potency of the midday Sun's UV radiation, one should avoid prolonged exposure. Limit sun-induced ocular harm with sunglasses that feature UVA and UVB filtration.
Updated: Aug 17, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the usual temperature for Santa Clara in September?

In September, the average high-temperature and low-temperature are 79.2°F (26.2°C) and 55.6°F (13.1°C) respectively. In August, the average heat index (a.k.a. 'real feel', 'apparent temperature'), which combines relative humidity and air temperature, is appraised at 84.2°F (29°C).

What is the least humid month?

July and September, with an average relative humidity of 61%, are the least humid months.

What is the average humidity in September?

In September, the average relative humidity is 61%.

How many days does it rain in September?

In Santa Clara, California, in September, during 2.7 rainfall days, 0.12" (3mm) of precipitation is typically accumulated.

How many hours of daylight does Santa Clara have in September?

In Santa Clara, California, the average day length in September is 12h and 25min.

What time are sunrise and sunset in September in Santa Clara?

In September, on the first day of the month, sunrise is at 6:39 am and sunset at 7:36 pm. On the last day of the month, sunrise is at 7:03 am and sunset at 6:51 pm PDT.

How long on average sun shines in September?

In Santa Clara, the average sunshine duration in September is 11.1h.

How high is the UV index in September in Santa Clara?

The average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium health risk from unsafe exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Santa Clara, CA

Average temperature in September - Santa Clara, CA
  • Average high temperature in September: 79.2°F

The warmest month (with the highest average high temperature) is July (81.9°F).
The month with the lowest average high temperature is December (56.7°F).

  • Average low temperature in September: 55.6°F

The month with the highest average low temperature is August (56.3°F).
The coldest months (with the lowest average low temperature) are January and February (43.3°F).

Average pressure in September
Santa Clara, CA

Average pressure in September - Santa Clara, 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).

Average wind speed in September
Santa Clara, CA

Average wind speed in September - Santa Clara, 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 month (with the lowest average wind speed) is September (4.4mph).

Average humidity in September
Santa Clara, CA

Average humidity in September - Santa Clara, CA
  • Average humidity in September: 61%

The month with the highest relative humidity is March (73%).
The months with the lowest relative humidity are July and September (61%).

Average rainfall in September
Santa Clara, CA

Average rainfall in September - Santa Clara, CA
  • Average rainfall in September: 0.12"

The wettest month (with the highest rainfall) is March (1.77").
The driest months (with the least rainfall) are July and August (0.04").

Average rainfall days in September
Santa Clara, CA

Average rainfall days in September - Santa Clara, CA
  • Average rainfall days in September: 2.7 days

The month with the highest number of rainy days is March (12.9 days).
The month with the least rainy days is August (0.8 days).

Average daylight in September /
Average sunshine in September
Santa Clara, CA

Average daylight in September / Average sunshine in September - Santa Clara, CA
  • Average daylight in September: 12h and 2min

The month with the longest days is June (Average daylight: 14h and 42min).
The month with the shortest days is December (Average daylight: 9h and 36min).

  • Average sunshine in September: 11h and 1min

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).

Average sunshine days in September
Santa Clara, CA

Average sunshine days in September - Santa Clara, CA
  • Average sunshine days in September: 25.8 days

The month with the most sunshine days is August (29.2 days).
The month with the least sunshine days is March (16.7 days).

Average UV index in September
Santa Clara, CA

Average UV index in September - Santa Clara, 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).

Average cloud cover in September
Santa Clara, CA

Average cloud cover in September - Santa Clara, 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).

Average visibility in September
Santa Clara, CA

Average visibility in September - Santa Clara, 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).

Santa Clara, California, USA

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