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
As Aliso Viejo transitions from August to September, the average high-temperatures adjust to a still warm 79.5°F (26.4°C), nearly the same as the previous 80.2°F (26.8°C). Throughout September, the temperature tends to fall to a consistent average low of 63.5°F (17.5°C).Humidity
The average relative humidity in September is 64%.Rainfall
In September, the rain falls for 4.6 days. Throughout September, 0.28" (7mm) of precipitation is accumulated. Throughout the year, there are 66.3 rainfall days, and 5.67" (144mm) of precipitation is accumulated.Daylight
In September, the average length of the day is 12h and 22min.On the first day of the month, sunrise is at 6:25 am and sunset at 7:15 pm. On the last day of September, sunrise is at 6:45 am and sunset at 6:36 pm PDT.
Sunshine
The average sunshine in September is 10.5h.UV index
The months with the highest UV index are June through September, with an average maximum UV index of 6. A UV Index of 6 to 7 symbolizes a high health vulnerability from exposure to the Sun's UV rays for average individuals.Note: In September, the maximum UV index of 6 translates into these guidelines:
Deter overexposure. Protecting against the sun's effects is essential. Avoid direct Sun exposure and seek shade from 10 a.m. to 4 p.m., the period of highest UV radiation. Remember, however, that not all shade structures offer full protection. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the temperature in September in Aliso Viejo?
What is the average humidity in September?
How many days does it rain in September?
How many hours of daylight does Aliso Viejo have in September?
When are sunrise and sunset in September?
How many hours of sunshine does Aliso Viejo have in September?
When is the highest UV index?
How high is the UV index in September?
Average temperature in September
Aliso Viejo, CA
- Average high temperature in September: 79.5°F
The warmest month (with the highest average high temperature) is August (80.2°F).
The month with the lowest average high temperature is December (62.8°F).
- Average low temperature in September: 63.5°F
The month with the highest average low temperature is August (64.4°F).
The coldest month (with the lowest average low temperature) is February (49.6°F).
Average pressure in September
Aliso Viejo, CA
- Average pressure in September: 29.89"Hg
The month with the highest atmospheric pressure is January (30.09"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).
Average wind speed in September
Aliso Viejo, CA
- Average wind speed in September: 4.7mph
The windiest month (with the highest average wind speed) is April (5.9mph).
The calmest months (with the lowest average wind speed) are August, September and October (4.7mph).
Average humidity in September
Aliso Viejo, CA
- Average humidity in September: 64%
The month with the highest relative humidity is June (71%).
The month with the lowest relative humidity is November (56%).
Average rainfall in September
Aliso Viejo, CA
- Average rainfall in September: 0.28"
The wettest month (with the highest rainfall) is December (0.87").
The driest month (with the least rainfall) is June (0.08").
Average rainfall days in September
Aliso Viejo, CA
- Average rainfall days in September: 4.6 days
The month with the highest number of rainy days is March (8.3 days).
The month with the least rainy days is June (2.6 days).
Average daylight in September /
Average sunshine in September
Aliso Viejo, CA
- Average daylight in September: 12h and 2min
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: 10h and 3min
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
Aliso Viejo, CA
- Average sunshine days in September: 21.7 days
The month with the most sunshine days is January (24.1 days).
The month with the least sunshine days is February (19.6 days).
Average UV index in September
Aliso Viejo, CA
- Average UV index in September: 6
The months with the highest UV index are June, 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
Aliso Viejo, CA
- Average cloud cover in September: 11
The months with the most cloud cover are March and December (Cloud cover 25).
The month with the least cloud cover is August (Cloud cover 7).
Average visibility in September
Aliso Viejo, 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).
Aliso Viejo, California, USA
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