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
As September takes hold, the average high-temperature is a pleasant 72.3°F (22.4°C), nearly mirroring that of the previous month. During September nights, Clear Lake records an average temperature of 53.8°F (12.1°C).Humidity
In September, the average relative humidity is 78%.Rainfall
In Clear Lake, Iowa, in September, it is raining for 12.5 days, with typically 2.52" (64mm) of accumulated precipitation. In Clear Lake, during the entire year, the rain falls for 145.9 days and collects up to 28.82" (732mm) of precipitation.Snowfall
June through September are months without snowfall.Daylight
In Clear Lake, the average length of the day in September is 12h and 29min.On the first day of the month, sunrise is at 6:38 am and sunset at 7:47 pm. On the last day of September, in Clear Lake, sunrise is at 7:10 am and sunset at 6:55 pm CDT.
Sunshine
The average sunshine in September is 9h.UV index
In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a medium vulnerability from exposure to the Sun's UV rays for average individuals.Note: In September, a regular UV index of 4 translates into these guidelines:
Adopt protective measures - Suggestions to resist sunburn are offered. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. Experience reduced UV exposure by about half when donning a wide-brim hat.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
Does it snow in September?
What is the average length of the day in September?
What time are sunrise and sunset in September?
How many hours of sunshine does Clear Lake have in September?
How high is the UV index in September?
Average temperature in September
Clear Lake, IA
- Average high temperature in September: 72.3°F
The warmest month (with the highest average high temperature) is July (79.3°F).
The month with the lowest average high temperature is January (22.3°F).
- Average low temperature in September: 53.8°F
The month with the highest average low temperature is July (62.6°F).
The coldest month (with the lowest average low temperature) is January (9.9°F).
Average pressure in September
Clear Lake, IA
- Average pressure in September: 30.01"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).
Average wind speed in September
Clear Lake, IA
- Average wind speed in September: 8.5mph
The windiest months (with the highest average wind speed) are January and April (10.9mph).
The calmest months (with the lowest average wind speed) are July and August (7.3mph).
Average humidity in September
Clear Lake, IA
- Average humidity in September: 78%
The month with the highest relative humidity is January (89%).
The month with the lowest relative humidity is October (71%).
Average rainfall in September
Clear Lake, IA
- Average rainfall in September: 2.52"
The wettest month (with the highest rainfall) is June (4.65").
The driest month (with the least rainfall) is January (1.06").
Average rainfall days in September
Clear Lake, IA
- Average rainfall days in September: 12.5 days
The month with the highest number of rainy days is June (19.8 days).
The month with the least rainy days is February (3.8 days).
Average snowfall in September
Clear Lake, IA
- Average snowfall in September: 0"
The month with the highest snowfall is February (7.48").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Clear Lake, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (14.6 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Clear Lake, IA
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- Average sunshine in September: 9h and 0min
The month with the most sunshine is July (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 30min).
Average sunshine days in September
Clear Lake, IA
- Average sunshine days in September: 15.1 days
The month with the most sunshine days is November (17.2 days).
The month with the least sunshine days is June (8 days).
Average UV index in September
Clear Lake, IA
- Average UV index in September: 4
The month with the highest UV index is June (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in September
Clear Lake, IA
- Average cloud cover in September: 33
The month with the most cloud cover is January (Cloud cover 63).
The month with the least cloud cover is August (Cloud cover 32).
Average visibility in September
Clear Lake, IA
- Average visibility in September: 6mi
The months with the highest visibility are March, April, May, June, August, September, October and November (6mi).
The months with the lowest visibility are January, February, July and December (5mi).
Clear Lake, Iowa, USA
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