September weather forecastMission Viejo, CA
September
Weather in September
September, the first month of the autumn in Mission Viejo, is still a warm month, with an average temperature varying between 63.3°F (17.4°C) and 79.7°F (26.5°C).Temperature
Mission Viejo indicates an average high-temperature of a still moderately hot 79.7°F (26.5°C) in September, showing minor variation from August's 80.8°F (27.1°C). Throughout September, Mission Viejo witnesses a consistent average low-temperature of 63.3°F (17.4°C).Humidity
The average relative humidity in September in Mission Viejo is 63%.Rainfall
In September, the rain falls for 4.4 days. Throughout September, 0.24" (6mm) of precipitation is accumulated. Throughout the year, there are 64.1 rainfall days, and 5.67" (144mm) of precipitation is accumulated.Daylight
The average length of the day in September 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 6:44 am and sunset at 6:35 pm PDT.
Sunshine
In September, the average sunshine 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 estimate of 6 to 7 represents a high health hazard from exposure to the Sun's UV radiation for ordinary individuals.Note: A maximum daily UV index of 6 during September morphs into the following directions:
Adopt measures and apply sun safety strategies. Shielding from skin and eye damage is necessary. UV radiation from the sun is at its strongest between 10 a.m. and 4 p.m. Try to limit direct exposure during these hours. 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
Average temperature in September
Mission Viejo, CA
- Average high temperature in September: 79.7°F
The warmest month (with the highest average high temperature) is August (80.8°F).
The month with the lowest average high temperature is December (63°F).
- Average low temperature in September: 63.3°F
The month with the highest average low temperature is August (64°F).
The coldest month (with the lowest average low temperature) is February (48.7°F).
Average pressure in September
Mission Viejo, CA
- Average pressure in September: 29.88"Hg
The month with the highest atmospheric pressure is January (30.1"Hg).
The months with the lowest atmospheric pressure are June and September (29.88"Hg).
Average wind speed in September
Mission Viejo, CA
- Average wind speed in September: 4.6mph
The windiest month (with the highest average wind speed) is April (5.8mph).
The calmest month (with the lowest average wind speed) is August (4.5mph).
Average humidity in September
Mission Viejo, CA
- Average humidity in September: 63%
The months with the highest relative humidity are May and June (70%).
The month with the lowest relative humidity is November (56%).
Average rainfall in September
Mission Viejo, CA
- Average rainfall in September: 0.24"
The wettest month (with the highest rainfall) is December (0.98").
The driest month (with the least rainfall) is June (0.08").
Average rainfall days in September
Mission Viejo, CA
- Average rainfall days in September: 4.4 days
The month with the highest number of rainy days is March (8.4 days).
The month with the least rainy days is June (2.3 days).
Average daylight in September /
Average sunshine in September
Mission Viejo, 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: 10h and 30min
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
Mission Viejo, CA
- Average sunshine days in September: 22.1 days
The months with the most sunshine days are January and August (24.4 days).
The month with the least sunshine days is May (19.5 days).
Average UV index in September
Mission 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
Mission 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
Mission 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).
