Contents
- Weather in September
- Frequently asked questions
- Average temperature in September
- Average pressure in September
- Average wind speed in September
- Average humidity in September
- Average rainfall in September
- Average rainfall days in September
- Average daylight in September
- Average sunshine in September
- Average sunshine days in September
- Average UV index in September
- Average cloud cover in September
- Average visibility in September
Weather in September
Temperature
The advent of September reveals an average high-temperature of a still moderately hot 77.5°F (25.3°C), showing minimal difference from the prior month. Cupertino experiences a drastic reduction from day temperatures to an average low of 55.8°F (13.2°C) in September.Humidity
The months with the lowest humidity in Cupertino, California, are July, September and October, with an average relative humidity of 64%.Rainfall
In Cupertino, during September, the rain falls for 2.5 days and regularly aggregates up to 0.08" (2mm) of precipitation. In Cupertino, California, during the entire year, the rain falls for 53.6 days and collects up to 5.39" (137mm) of precipitation.Daylight
In Cupertino, 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 6:52 pm PDT.
Sunshine
In September, the average sunshine is 11.1h.UV index
In Cupertino, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for average individuals.Note: The maximum UV index of 5 during September translates into these guidelines:
Stay alert. Light-skinned people could suffer burns in less than 30 minutes. Midday is the peak time for the Sun's radiation; stay in the shade and protect yourself. Arm yourself against UV rays' harm with protective apparel and UV-filtering shades.
Frequently asked questions
What are September temperatures in Cupertino?
What are the least humid months in Cupertino?
What is the average humidity in September in Cupertino?
How many days does it rain in September in Cupertino?
What is the average length of the day in September in Cupertino?
What time are sunrise and sunset in September in Cupertino?
How long on average sun shines in September in Cupertino?
What is the UV index reading in September in Cupertino?
Average temperature in September
Cupertino, CA
- Average high temperature in September: 77.5°F
The warmest month (with the highest average high temperature) is July (79.3°F).
The month with the lowest average high temperature is December (57°F).
- Average low temperature in September: 55.8°F
The month with the highest average low temperature is August (56.1°F).
The coldest months (with the lowest average low temperature) are February and March (44.2°F).
Average pressure in September
Cupertino, CA
- Average pressure in September: 29.92"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is September (29.92"Hg).
Average wind speed in September
Cupertino, CA
- Average wind speed in September: 4.6mph
The windiest month (with the highest average wind speed) is April (6.2mph).
The calmest month (with the lowest average wind speed) is September (4.6mph).
Average humidity in September
Cupertino, CA
- Average humidity in September: 64%
The month with the highest relative humidity is March (74%).
The months with the lowest relative humidity are July, September and October (64%).
Average rainfall in September
Cupertino, CA
- Average rainfall in September: 0.08"
The wettest month (with the highest rainfall) is February (1.02").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in September
Cupertino, CA
- Average rainfall days in September: 2.5 days
The month with the highest number of rainy days is March (9 days).
The month with the least rainy days is August (0.8 days).
Average daylight in September /
Average sunshine in September
Cupertino, 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 months with the most sunshine are July and August (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 54min).
Average sunshine days in September
Cupertino, CA
- Average sunshine days in September: 26.5 days
The month with the most sunshine days is August (28.5 days).
The months with the least sunshine days are February and March (20.8 days).
Average UV index in September
Cupertino, CA
- Average UV index in September: 5
The month with the highest UV index is June (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 3).
Average cloud cover in September
Cupertino, 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 7).
Average visibility in September
Cupertino, 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).
Cupertino, California, USA
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