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
Transitioning from August to September, Fairfax observes an average high-temperature of a still warm 74.3°F (23.5°C), differing subtly from the previous month. During September, Fairfax's temperature falls to a steady low-temperature average of 55.2°F (12.9°C).Humidity
The average relative humidity in September is 77%.Rainfall
In September, the rain falls for 10.9 days. Throughout September, 1.73" (44mm) of precipitation is accumulated. In Fairfax, during the entire year, the rain falls for 120.7 days and collects up to 18.31" (465mm) of precipitation.Snowfall
May through September are months without snowfall.Daylight
In Fairfax, the average length of the day in September is 12h and 28min.On the first day of the month, sunrise is at 6:33 am and sunset at 7:40 pm. On the last day of September, sunrise is at 7:03 am and sunset at 6:49 pm CDT.
Sunshine
The average sunshine in September is 9.3h.UV index
The average daily maximum UV index in September in Fairfax is 4. A UV Index value of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for average individuals.Note: In September, the average maximum UV index of 4 translates into the following recommendations:
Exercise care. People with light skin might get burns in fewer than 30 minutes. Minimize direct exposure to the Sun during midday when its radiation is at its peak. A wide-brimmed hat is a shield, deflecting up to 50% of harmful UV radiation from eyes.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for Fairfax in September?
What is the average humidity in September?
How many days 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 in Fairfax?
When is the sunrise / sunset in September?
How long on average sun shines in September?
How high is the UV index in September?
Average temperature in September
Fairfax, IA
- Average high temperature in September: 74.3°F
The warmest month (with the highest average high temperature) is July (80.8°F).
The month with the lowest average high temperature is January (26.2°F).
- Average low temperature in September: 55.2°F
The month with the highest average low temperature is July (64.6°F).
The coldest month (with the lowest average low temperature) is January (14.2°F).
Average pressure in September
Fairfax, IA
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.9"Hg).
Average wind speed in September
Fairfax, IA
- Average wind speed in September: 8mph
The windiest months (with the highest average wind speed) are January and April (10.7mph).
The calmest months (with the lowest average wind speed) are July and August (7mph).
Average humidity in September
Fairfax, IA
- Average humidity in September: 77%
The month with the highest relative humidity is January (85%).
The month with the lowest relative humidity is October (73%).
Average rainfall in September
Fairfax, IA
- Average rainfall in September: 1.73"
The wettest month (with the highest rainfall) is May (3.07").
The driest months (with the least rainfall) are January and February (0.63").
Average rainfall days in September
Fairfax, IA
- Average rainfall days in September: 10.9 days
The month with the highest number of rainy days is May (16 days).
The month with the least rainy days is February (3 days).
Average snowfall in September
Fairfax, IA
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.64").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Fairfax, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (10.3 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Fairfax, 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 0min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).
Average sunshine days in September
Fairfax, IA
- Average sunshine days in September: 18.2 days
The month with the most sunshine days is October (19.9 days).
The month with the least sunshine days is June (11.8 days).
Average UV index in September
Fairfax, 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 and December (UV index 1).
Average cloud cover in September
Fairfax, IA
- Average cloud cover in September: 30
The month with the most cloud cover is January (Cloud cover 57).
The months with the least cloud cover are August and September (Cloud cover 30).
Average visibility in September
Fairfax, IA
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, August, September, October, November and December (6mi).
The month with the lowest visibility is July (5mi).
Fairfax, Iowa, USA
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