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
September's beginning signals an average high-temperature of a still warm 74.8°F (23.8°C), barely different from August's 79.9°F (26.6°C). Griffen witnesses an average low-temperature of 55.8°F (13.2°C) throughout the month of September.Humidity
In Griffen, the average relative humidity in September is 76%.Rainfall
In Griffen, in September, it is raining for 11.1 days, with typically 2.4" (61mm) of accumulated precipitation. Throughout the year, there are 123.3 rainfall days, and 20.98" (533mm) of precipitation is accumulated.Snowfall
In Griffen, snow does not fall in June through September.Daylight
In September, the average length of the day is 12h and 28min.On the first day of September, 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
The average sunshine in September is 9.3h.UV index
In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes a moderate health risk from unsafe exposure to UV radiation for ordinary individuals.Note: In September, an average UV index of 4 transforms into the following instructions:
Take necessary precautions - Protection from skin and eye injury is mandatory. Avoiding the Sun's peak radiation during midday hours is essential for health and safety. Employ a hat with a wide brim for robust protection, cutting UV exposure by half.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are the temperatures in September?
What is the average humidity in September?
How much does it rain in September?
When it does not snow?
Does it snow in September?
How many hours of daylight does Griffen have in September?
When is the sunrise / sunset in September?
How long on average sun shines in September?
What is the UV index reading in September?
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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