September weather forecastWinterhaven, CA
September
Weather in September
September, the first month of the autumn in Winterhaven, is also a fiery hot month, with an average temperature varying between 99.5°F (37.5°C) and 81°F (27.2°C).Temperature
The beginning of September brings a minor change in the average high-temperature, shifting from a blistering 105.1°F (40.6°C) in August to a torrid 99.5°F (37.5°C). Throughout September, the nighttime temperature averages to a warm 81°F (27.2°C).Humidity
The average relative humidity in September is 29%.Rainfall
The months with the most rainfall are July and September, with an average 0.39" (10mm) of precipitation.Daylight
The average length of the day in September is 12h and 22min.On the first day of the month, sunrise is at 6:13 am and sunset at 7:02 pm. On the last day of September, sunrise is at 6:32 am and sunset at 6:23 pm PDT.
Sunshine
In Winterhaven, the average sunshine in September is 9.8h.UV index
The months with the highest UV index are June through September, with an average maximum UV index of 8. A UV Index value of 8 to 10 symbolizes a very high health vulnerability from exposure to the Sun's UV radiation for the average person.Note: A typical high UV index of 8 in September suggests the following recommendations:
Prioritize protection; rapid damage can occur to unprotected eyes and skin. Minimize exposure to direct sunlight and seek shade from 10 a.m. to 4 p.m., when UV radiation is most intense, but remember that shade structures may not offer complete protection. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Winterhaven, CA
- Average high temperature in September: 99.5°F
The warmest month (with the highest average high temperature) is July (105.3°F).
The month with the lowest average high temperature is December (66°F).
- Average low temperature in September: 81°F
The month with the highest average low temperature is August (86.4°F).
The coldest month (with the lowest average low temperature) is December (50.5°F).
Average pressure in September
Winterhaven, CA
- Average pressure in September: 29.78"Hg
The month with the highest atmospheric pressure is January (30.07"Hg).
The month with the lowest atmospheric pressure is June (29.74"Hg).
Average wind speed in September
Winterhaven, CA
- Average wind speed in September: 6.9mph
The windiest months (with the highest average wind speed) are April and July (8.5mph).
The calmest month (with the lowest average wind speed) is November (6.6mph).
Average humidity in September
Winterhaven, CA
- Average humidity in September: 29%
The month with the highest relative humidity is December (38%).
The month with the lowest relative humidity is June (22%).
Average rainfall in September
Winterhaven, CA
- Average rainfall in September: 0.39"
The wettest months (with the highest rainfall) are July and September (0.39").
The driest months (with the least rainfall) are May and June (0.04").
Average rainfall days in September
Winterhaven, CA
- Average rainfall days in September: 4.6 days
The month with the highest number of rainy days is July (5.8 days).
The month with the least rainy days is May (0.8 days).
Average daylight in September /
Average sunshine in September
Winterhaven, CA
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 18min).
The month with the shortest days is December (Average daylight: 10h and 0min).
- Average sunshine in September: 9h and 48min
The month with the most sunshine is June (Average sunshine: 12h and 12min).
The month with the least sunshine is December (Average sunshine: 7h and 12min).
Average sunshine days in September
Winterhaven, CA
- Average sunshine days in September: 23 days
The month with the most sunshine days is May (30.2 days).
The month with the least sunshine days is July (22.1 days).
Average UV index in September
Winterhaven, CA
- Average UV index in September: 8
The months with the highest UV index are June, July, August and September (UV index 8).
The months with the lowest UV index are November and December (UV index 4).
Average cloud cover in September
Winterhaven, CA
- Average cloud cover in September: 8
The month with the most cloud cover is December (Cloud cover 17).
The month with the least cloud cover is June (Cloud cover 5).
Average visibility in September
Winterhaven, 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).





