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
In September, Griffen experiences a minor shift in meteorological conditions with average high-temperatures marked at a still moderately hot 74.8°F (23.8°C), closely mirroring the climate in August. The month of September records an average low-temperature of 55.8°F (13.2°C).Humidity
The average relative humidity in September is 76%.Rainfall
In September, the rain falls for 11.1 days. Throughout September, 2.4" (61mm) of precipitation is accumulated. In Griffen, during the entire year, the rain falls for 123.3 days and collects up to 20.98" (533mm) of precipitation.Snowfall
In Griffen, Iowa, snow does not fall in June through September.Daylight
In Griffen, Iowa, the average length of the day in September is 12h and 28min.On the first day of September in Griffen, sunrise is at 6:41 am and sunset at 7:48 pm. On the last day of the month, sunrise is at 7:11 am and sunset at 6:57 pm CDT.
Sunshine
In Griffen, Iowa, the average sunshine in September is 9.3h.UV index
The average daily maximum UV index in September in Griffen is 4. A UV Index estimate of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV radiation for average individuals.Note: The maximum UV index of 4 during September translates into these guidelines:
Take necessary precautions - Suggestions to elude sunburn are provided. The solar radiation around mid-day is intense; avoid the Sun and stay safe. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly.
Frequently asked questions
What are September temperatures in Griffen?
What is the average humidity in September in Griffen?
How much does it rain in Griffen in September?
When it does not snow in Griffen?
Does it snow in Griffen in September?
How many hours of daylight does Griffen have in September?
When is the sunrise / sunset in September in Griffen?
How many hours of sunshine does Griffen have in September?
How high is the UV index in September in Griffen?
Average temperature in September
Griffen, IA
- Average high temperature in September: 74.8°F
The warmest month (with the highest average high temperature) is July (81.3°F).
The month with the lowest average high temperature is January (26.4°F).
- Average low temperature in September: 55.8°F
The month with the highest average low temperature is July (64.4°F).
The coldest month (with the lowest average low temperature) is January (13.1°F).
Average pressure in September
Griffen, IA
- Average pressure in September: 30.01"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.88"Hg).
Average wind speed in September
Griffen, IA
- Average wind speed in September: 8.2mph
The windiest month (with the highest average wind speed) is April (10.7mph).
The calmest months (with the lowest average wind speed) are July and August (7.1mph).
Average humidity in September
Griffen, IA
- Average humidity in September: 76%
The month with the highest relative humidity is January (84%).
The month with the lowest relative humidity is October (69%).
Average rainfall in September
Griffen, IA
- Average rainfall in September: 2.4"
The wettest month (with the highest rainfall) is June (3.35").
The driest month (with the least rainfall) is January (0.67").
Average rainfall days in September
Griffen, IA
- Average rainfall days in September: 11.1 days
The month with the highest number of rainy days is June (17.4 days).
The month with the least rainy days is February (3.2 days).
Average snowfall in September
Griffen, IA
- Average snowfall in September: 0"
The month with the highest snowfall is February (3.07").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Griffen, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (10.9 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Griffen, IA
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in September: 9h and 2min
The month with the most sunshine is July (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).
Average sunshine days in September
Griffen, IA
- Average sunshine days in September: 16.5 days
The month with the most sunshine days is October (19.5 days).
The month with the least sunshine days is June (10.5 days).
Average UV index in September
Griffen, IA
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January, February, October, November and December (UV index 2).
Average cloud cover in September
Griffen, IA
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 56).
The month with the least cloud cover is September (Cloud cover 30).
Average visibility in September
Griffen, IA
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are January, July and August (5mi).
Griffen, Iowa, USA
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