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 brings a slight decrease in the average high-temperature, shifting from an enjoyable 63.7°F (17.6°C) in August to a mild 57.6°F (14.2°C). A steady average of 33.4°F (0.8°C) throughout September underscores a considerable divergence from the daytime high.Humidity
The average relative humidity in September is 59%.Rainfall
In September, the rain falls for 11.5 days. Throughout September, 1.46" (37mm) of precipitation is accumulated. In Jefferson, during the entire year, the rain falls for 110.4 days and collects up to 24.09" (612mm) of precipitation.Snowfall
Months with snowfall are January through December. In September, it is snowing for 5.5 days. Throughout September, 2.05" (52mm) of snow is accumulated. Throughout the year, in Jefferson, there are 158 snowfall days, and 118.82" (3018mm) of snow is accumulated.Daylight
In September, the average length of the day in Jefferson is 12h and 26min.On the first day of September, sunrise is at 6:32 am and sunset at 7:33 pm. On the last day of the month, sunrise is at 6:59 am and sunset at 6:46 pm MDT.
Sunshine
In Jefferson, the average sunshine in September is 10.5h.UV index
In September, the average daily maximum UV index is 2. A UV Index of 2, and less, symbolizes a low health risk from unprotected exposure to Sun's UV rays for ordinary individuals.Note: A maximum high UV index of 2 in September translates into the following recommendations:
Although the majority can endure up to an hour in the sun without burns, children always require sun protection. Considering the strength of solar radiation at midday, one should avoid direct Sun exposure. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes. Take precaution! The reflection from snow can almost double the UV radiation of the Sun.
Frequently asked questions
What are September temperatures in Jefferson?
What is the average humidity in September in Jefferson?
How much does it rain in Jefferson in September?
How much does it snow in Jefferson in September?
How many hours of daylight does Jefferson have in September?
When is the sunrise / sunset in September in Jefferson?
How many hours of sunshine does Jefferson have in September?
What is the UV index reading in September in Jefferson?
Average temperature in September
Jefferson, CO
- Average high temperature in September: 57.6°F
The warmest month (with the highest average high temperature) is July (65.8°F).
The month with the lowest average high temperature is December (21.2°F).
- Average low temperature in September: 33.4°F
The month with the highest average low temperature is July (40.1°F).
The coldest months (with the lowest average low temperature) are January and December (0.7°F).
Average pressure in September
Jefferson, CO
- Average pressure in September: 30.05"Hg
The month with the highest atmospheric pressure is January (30.19"Hg).
The months with the lowest atmospheric pressure are April and May (29.94"Hg).
Average wind speed in September
Jefferson, CO
- Average wind speed in September: 5.2mph
The windiest month (with the highest average wind speed) is February (7mph).
The calmest month (with the lowest average wind speed) is August (4.8mph).
Average humidity in September
Jefferson, CO
- Average humidity in September: 59%
The month with the highest relative humidity is February (89%).
The month with the lowest relative humidity is June (54%).
Average rainfall in September
Jefferson, CO
- Average rainfall in September: 1.46"
The wettest month (with the highest rainfall) is July (3.35").
The driest month (with the least rainfall) is November (1.14").
Average rainfall days in September
Jefferson, CO
- Average rainfall days in September: 11.5 days
The month with the highest number of rainy days is July (22.8 days).
The month with the least rainy days is November (2.8 days).
Average snowfall in September
Jefferson, CO
- Average snowfall in September: 2.05"
The month with the highest snowfall is May (19.69").
The month with the least snowfall is July (0.24").
Average snowfall days in September
Jefferson, CO
- Average snowfall days in September: 5.5 days
The month with the highest number of snowfall days is April (22.8 days).
The month with the least snowfall days is July (1.3 days).
Average daylight in September /
Average sunshine in September
Jefferson, CO
- 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 24min).
- Average sunshine in September: 10h and 3min
The month with the most sunshine is June (Average sunshine: 11h and 24min).
The month with the least sunshine is February (Average sunshine: 5h and 12min).
Average sunshine days in September
Jefferson, CO
- Average sunshine days in September: 14.1 days
The month with the most sunshine days is November (18.5 days).
The month with the least sunshine days is July (5.8 days).
Average UV index in September
Jefferson, CO
- Average UV index in September: 2
The months with the highest UV index are May, June, July and August (UV index 3).
The months with the lowest UV index are February and December (UV index 1).
Average cloud cover in September
Jefferson, CO
- Average cloud cover in September: 22
The month with the most cloud cover is February (Cloud cover 54).
The month with the least cloud cover is June (Cloud cover 19).
Average visibility in September
Jefferson, CO
- Average visibility in September: 6mi
The months with the highest visibility are June, July, August, September and October (6mi).
The months with the lowest visibility are January, February, March, April and December (4mi).
Jefferson, Colorado, USA
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