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 snowfall in September
- Average snowfall 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
The average high-temperature is a moderately hot 85.1°F (29.5°C) in September, hardly different from the 90.1°F (32.3°C) recorded in August. Clearlake registers a significant drop in temperature in September, with average nighttime lows of 55.8°F (13.2°C).Heat index
The heat index value during September is calculated to be a hot 86°F (30°C). If one sustains activity during exposure, it could lead to a sense of fatigue, with a chance of heat cramps.Heat index readings emphasize conditions of light breezes and shaded spots. Heat index values may surge by up to 15 Fahrenheit (8 Celsius) degrees in the presence of direct sunlight.
Note: The heat index, also known as 'felt air temperature' or 'feels like', is a single figure representing how weather conditions feel when combining temperature and humidity. The influence of weather is personal, with a diverse population experiencing it differently due to differences in body mass, stature, and degree of activity. Keep in mind that direct sunshine exposure can amplify the weather's effects, possibly increasing the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values hold great significance to children. Young ones often ignore the need to take a break and drink fluids. Thirst is a late-stage symptom of dehydration - hence, maintaining hydration, particularly during extended physical activities, is crucial.
Humidity
In Clearlake, the average relative humidity in September is 45%.Rainfall
In September, in Clearlake, the rain falls for 2.1 days. Throughout September, 0.08" (2mm) of precipitation is accumulated. In Clearlake, during the entire year, the rain falls for 79.8 days and collects up to 17.44" (443mm) of precipitation.Snowfall
April through October are months without snowfall.Daylight
In Clearlake, the average length of the day in September is 12h and 25min.On the first day of the month, sunrise is at 6:40 am and sunset at 7:40 pm. On the last day of September, sunrise is at 7:06 am and sunset at 6:54 pm PDT.
Sunshine
In Clearlake, the average sunshine in September is 11.1h.UV index
In September, the average daily maximum UV index in Clearlake is 5. A UV Index reading of 3 to 5 represents a moderate threat to health from unsafe exposure to UV radiation for the average person.Note: The maximum UV index, 5 during September, leads to the following recommendations:
Take precautions - Protection against skin and eye damage is obliged. Midday Sun has the strongest UV rays, making it crucial to limit exposure and find shade. Wearing a wide-brim hat can block approximately 50% of UV radiation, protecting the eyes.
Frequently asked questions
How hot is September in Clearlake?
What is the average humidity in September in Clearlake?
How much does it rain in Clearlake in September?
When it does not snow in Clearlake?
How many hours of daylight does Clearlake have in September?
What time are sunrise and sunset in September in Clearlake?
How long on average sun shines in September in Clearlake?
What is the UV index reading in September in Clearlake?
Average temperature in September
Clearlake, CA
- Average high temperature in September: 85.1°F
The warmest month (with the highest average high temperature) is July (91.2°F).
The month with the lowest average high temperature is December (52.7°F).
- Average low temperature in September: 55.8°F
The month with the highest average low temperature is July (58.8°F).
The coldest month (with the lowest average low temperature) is December (38.1°F).
Average pressure in September
Clearlake, CA
- Average pressure in September: 29.92"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The months with the lowest atmospheric pressure are June and August (29.91"Hg).
Average wind speed in September
Clearlake, CA
- Average wind speed in September: 4.6mph
The windiest month (with the highest average wind speed) is April (5.7mph).
The calmest month (with the lowest average wind speed) is November (4.3mph).
Average humidity in September
Clearlake, CA
- Average humidity in September: 45%
The month with the highest relative humidity is March (74%).
The month with the lowest relative humidity is July (44%).
Average rainfall in September
Clearlake, CA
- Average rainfall in September: 0.08"
The wettest month (with the highest rainfall) is February (3.7").
The driest months (with the least rainfall) are July and August (0.04").
Average rainfall days in September
Clearlake, CA
- Average rainfall days in September: 2.1 days
The month with the highest number of rainy days is March (13.9 days).
The months with the least rainy days are July and August (1.1 days).
Average snowfall in September
Clearlake, CA
- Average snowfall in September: 0"
The month with the highest snowfall is February (0.51").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Clearlake, CA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (0.9 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Clearlake, CA
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in September: 11h and 1min
The month with the most sunshine is July (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 18min).
Average sunshine days in September
Clearlake, CA
- Average sunshine days in September: 27.1 days
The month with the most sunshine days is July (29.4 days).
The month with the least sunshine days is March (15.8 days).
Average UV index in September
Clearlake, CA
- Average UV index in September: 5
The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are November and December (UV index 2).
Average cloud cover in September
Clearlake, CA
- Average cloud cover in September: 9
The month with the most cloud cover is March (Cloud cover 43).
The month with the least cloud cover is July (Cloud cover 4).
Average visibility in September
Clearlake, 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).
Clearlake, California, USA
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