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
Fountain Valley transitions into September recording an average high-temperature of a still moderately hot 77.5°F (25.3°C), closely aligning with the preceding month's temperature. Fountain Valley's temperature lowers to a mean of 64.8°F (18.2°C) during the nights in September.Humidity
The average relative humidity in September is 65%.Rainfall
In Fountain Valley, in September, it is raining for 3.1 days, with typically 0.24" (6mm) of accumulated precipitation. In Fountain Valley, during the entire year, the rain falls for 59.1 days and collects up to 8.86" (225mm) of precipitation.Daylight
In Fountain Valley, the average length of the day in September is 12h and 22min.On the first day of the month, sunrise is at 6:26 am and sunset at 7:16 pm. On the last day of September, sunrise is at 6:46 am and sunset at 6:36 pm PDT.
Sunshine
In Fountain Valley, the average sunshine in September is 10.6h.UV index
The months with the highest UV index in Fountain Valley are July through September, with an average maximum UV index of 6. A UV Index estimate of 6 to 7 represents a high threat to health from unprotected exposure to Sun's UV rays for the ordinary person.Note: The daily high UV index of 6 in September translates into this advice:
Use measures and accept sun safety conventions. Guarding against skin and eye trauma is of high priority. The Sun emits the most powerful UV radiation between 10 a.m. and 4 p.m. Try to avoid direct sunlight during this period. Prioritize a wide-brim hat for comprehensive sun defense for your face, neck, eyes, and ears.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures in Fountain Valley?
What is the average humidity in September in Fountain Valley?
How many days does it rain in September in Fountain Valley?
What is the average length of the day in September in Fountain Valley?
What time are sunrise and sunset in September in Fountain Valley?
How long on average sun shines in September in Fountain Valley?
When is the highest UV index in Fountain Valley?
What is the UV index intensity in September in Fountain Valley?
Average temperature in September
Fountain Valley, CA
- Average high temperature in September: 77.5°F
The warmest month (with the highest average high temperature) is August (78.1°F).
The month with the lowest average high temperature is December (62.6°F).
- Average low temperature in September: 64.8°F
The month with the highest average low temperature is August (65.1°F).
The coldest month (with the lowest average low temperature) is February (51.8°F).
Average pressure in September
Fountain Valley, CA
- Average pressure in September: 29.89"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The months with the lowest atmospheric pressure are June and September (29.89"Hg).
Average wind speed in September
Fountain Valley, CA
- Average wind speed in September: 5.2mph
The windiest month (with the highest average wind speed) is April (6.5mph).
The calmest months (with the lowest average wind speed) are September and October (5.2mph).
Average humidity in September
Fountain Valley, CA
- Average humidity in September: 65%
The month with the highest relative humidity is June (72%).
The month with the lowest relative humidity is November (56%).
Average rainfall in September
Fountain Valley, CA
- Average rainfall in September: 0.24"
The wettest month (with the highest rainfall) is December (1.81").
The driest month (with the least rainfall) is June (0.04").
Average rainfall days in September
Fountain Valley, CA
- Average rainfall days in September: 3.1 days
The month with the highest number of rainy days is March (7.9 days).
The month with the least rainy days is August (2.1 days).
Average daylight in September /
Average sunshine in September
Fountain Valley, CA
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 10h and 0min).
- Average sunshine in September: 10h and 4min
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: 6h and 36min).
Average sunshine days in September
Fountain Valley, CA
- Average sunshine days in September: 24.2 days
The month with the most sunshine days is August (26.8 days).
The month with the least sunshine days is February (20 days).
Average UV index in September
Fountain Valley, CA
- Average UV index in September: 6
The months with the highest UV index are July, August and September (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 4).
Average cloud cover in September
Fountain Valley, CA
- Average cloud cover in September: 10
The months with the most cloud cover are March and December (Cloud cover 24).
The month with the least cloud cover is August (Cloud cover 7).
Average visibility in September
Fountain Valley, 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).
Fountain Valley, California, USA
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