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
September's presence records an average high-temperature of a still warm 76.5°F (24.7°C), closely mirroring August's climate. In September, the average low-temperature is a moderate 56.7°F (13.7°C).Humidity
The months with the lowest humidity are September and October, with an average relative humidity of 65%.Rainfall
In Palo Alto, in September, during 2.1 rainfall days, 0.08" (2mm) of precipitation is typically accumulated. In Palo Alto, during the entire year, the rain falls for 63.3 days and collects up to 9.53" (242mm) of precipitation.Daylight
In September, the average length of the day 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 11h.UV index
The months with the highest UV index are April through October, with an average maximum UV index of 5. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for ordinary individuals.Note: During September, 5 as the daily maximum UV index converts into the following advice:
Take precautions - Protection against sun damage is advised. Exposing oneself to the midday Sun can be harmful due to the strong UV radiation; limit your time outside. In the presence of strong sunlight, it's crucial to wear sunglasses that ward off UVA and UVB rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures?
What are the least humid months?
What is the average humidity in September?
How many days does it rain in September?
What is the average length of the day in September?
When is the sunrise / sunset in September?
How many hours of sunshine does Palo Alto have in September?
When is the highest UV index in Palo Alto?
What is the UV index reading in September?
Average temperature in September
Palo Alto, CA
- Average high temperature in September: 76.5°F
The warmest months (with the highest average high temperature) are July and August (77.5°F).
The month with the lowest average high temperature is December (56.3°F).
- Average low temperature in September: 56.7°F
The month with the highest average low temperature is August (57°F).
The coldest months (with the lowest average low temperature) are January and February (45.1°F).
Average pressure in September
Palo Alto, 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 and September (29.92"Hg).
Average wind speed in September
Palo Alto, CA
- Average wind speed in September: 4.9mph
The windiest months (with the highest average wind speed) are April and May (6.5mph).
The calmest months (with the lowest average wind speed) are September and October (4.9mph).
Average humidity in September
Palo Alto, CA
- Average humidity in September: 65%
The month with the highest relative humidity is March (74%).
The months with the lowest relative humidity are September and October (65%).
Average rainfall in September
Palo Alto, CA
- Average rainfall in September: 0.08"
The wettest month (with the highest rainfall) is February (2.01").
The driest month (with the least rainfall) is July (0").
Average rainfall days in September
Palo Alto, CA
- Average rainfall days in September: 2.1 days
The month with the highest number of rainy days is March (12.3 days).
The month with the least rainy days is August (0.6 days).
Average daylight in September /
Average sunshine in September
Palo Alto, 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 0min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 54min).
Average sunshine days in September
Palo Alto, CA
- Average sunshine days in September: 27.6 days
The month with the most sunshine days is July (30.2 days).
The month with the least sunshine days is March (18 days).
Average UV index in September
Palo Alto, CA
- Average UV index in September: 5
The months with the highest UV index are April, May, June, July, August, September and October (UV index 5).
The months with the lowest UV index are February, November and December (UV index 3).
Average cloud cover in September
Palo Alto, CA
- Average cloud cover in September: 11
The months with the most cloud cover are March and December (Cloud cover 34).
The month with the least cloud cover is July (Cloud cover 6).
Average visibility in September
Palo Alto, 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).
Palo Alto, California, USA
Weather forecast for your location
2. Allow the app to use your location