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
Lake Forest's shift into September is marked by a subtle change to a still warm 81°F (27.2°C) from August's 82°F (27.8°C) in temperature. An average low-temperature of 63.7°F (17.6°C) marks the nights in Lake Forest throughout September.Heat index
September's average heat index is calculated to be 82.4°F (28°C). If one endures exposure and continues to be active, it might result in tiredness and heat cramps.Be informed that the heat index values are oriented around shady conditions and gentle breezes. Heat index values have the potential to be boosted by 15 Fahrenheit (8 Celsius) degrees due to direct sunlight.
Note: The heat index, also known as 'felt air temperature' or 'real feel', combines both the air temperature and the humidity level to give a perceived human temperature. An individual's perception of weather can be affected by a variety of elements including metabolic differences, being pregnant, and their level of physical exertion. Take note that direct exposure to the sun can increase the felt temperature, possibly adding 15 Fahrenheit (8 Celsius) degrees to the heat index. Heat index values are especially vital to children. Younglings are generally more in peril than adults due to their reduced perspiration. Coupled with a larger skin surface relative to their tiny bodies and greater heat production because of their activity, they become more at risk.
Humidity
The average relative humidity in September is 61%.Rainfall
In September, the rain falls for 4.6 days. Throughout September, 0.31" (8mm) of precipitation is accumulated. In Lake Forest, during the entire year, the rain falls for 65.4 days and collects up to 9.17" (233mm) of precipitation.Daylight
In Lake Forest, 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, in Lake Forest, sunrise is at 6:44 am and sunset at 6:35 pm PDT.
Sunshine
In Lake Forest, the average sunshine in September is 10.6h.UV index
The months with the highest UV index are June through September, with an average maximum UV index of 6. A UV Index reading of 6 to 7 represents a high threat to health from exposure to the Sun's UV radiation for average individuals.Note: The maximum UV index, 6 during September, leads to the following recommendations:
Fend off overexposure. Sun protection is vital. 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. Sunglasses providing both UVA and UVB protection are non-negotiable on sunlit days.
Frequently asked questions
What are September temperatures in Lake Forest?
What is the average humidity in September in Lake Forest?
How much does it rain in Lake Forest in September?
How many hours of daylight does Lake Forest have in September?
When is the sunrise / sunset in September in Lake Forest?
How many hours of sunshine does Lake Forest have in September?
What is the month with the highest UV index in Lake Forest?
What is the UV index intensity in September in Lake Forest?
Average temperature in September
Lake Forest, CA
- Average high temperature in September: 81°F
The warmest month (with the highest average high temperature) is August (82°F).
The month with the lowest average high temperature is December (63.1°F).
- Average low temperature in September: 63.7°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 (48.7°F).
Average pressure in September
Lake Forest, 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
Lake Forest, CA
- Average wind speed in September: 4.5mph
The windiest months (with the highest average wind speed) are April and May (5.7mph).
The calmest months (with the lowest average wind speed) are August and September (4.5mph).
Average humidity in September
Lake Forest, CA
- Average humidity in September: 61%
The months with the highest relative humidity are May and June (69%).
The month with the lowest relative humidity is November (55%).
Average rainfall in September
Lake Forest, CA
- Average rainfall in September: 0.31"
The wettest month (with the highest rainfall) is December (1.85").
The driest month (with the least rainfall) is June (0.08").
Average rainfall days in September
Lake Forest, CA
- Average rainfall days in September: 4.6 days
The month with the highest number of rainy days is March (8.1 days).
The month with the least rainy days is June (2 days).
Average daylight in September /
Average sunshine in September
Lake Forest, 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
Lake Forest, CA
- Average sunshine days in September: 21.8 days
The months with the most sunshine days are January and October (24.2 days).
The month with the least sunshine days is May (19.3 days).
Average UV index in September
Lake Forest, 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
Lake Forest, 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 6).
Average visibility in September
Lake Forest, 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).
Lake Forest, California, USA
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