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
A moderate decline in average high-temperatures is noted in September, moving from a hot 87.1°F (30.6°C) in August to a moderately hot 79.5°F (26.4°C). Derby anticipates a stark contrast in temperature during September nights, with an average low of 53.8°F (12.1°C).Humidity
The average relative humidity in September is 41%.Rainfall
In Derby, Colorado, in September, it is raining for 3.3 days, with typically 0.16" (4mm) of accumulated precipitation. Throughout the year, in Derby, there are 48.3 rainfall days, and 3.19" (81mm) of precipitation is accumulated.Snowfall
June through September are months without snowfall.Daylight
In September, the average length of the day is 12h and 26min.On the first day of the month, sunrise is at 6:28 am and sunset at 7:30 pm. On the last day of September, sunrise is at 6:55 am and sunset at 6:43 pm MDT.
Sunshine
The average sunshine in September is 11.1h.UV index
The average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a medium health hazard from exposure to the Sun's UV rays for average individuals.Note: A maximum high UV index of 5 in September translates into the following recommendations:
Preventative actions are necessary - Suggestions to safeguard against sun damage are in order. Limiting exposure to the direct Sun during midday hours can help prevent harmful UV radiation effects. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage.
Frequently asked questions
What is the usual temperature for Derby in September?
What is the average humidity in September in Derby?
How many days does it rain in September in Derby?
When it does not snow in Derby?
Does it snow in Derby in September?
How many hours of daylight does Derby have in September?
When is the sunrise / sunset in September in Derby?
How long on average sun shines in September in Derby?
How high is the UV index in September in Derby?
Average temperature in September
Derby, CO
- Average high temperature in September: 79.5°F
The warmest month (with the highest average high temperature) is July (88.3°F).
The month with the lowest average high temperature is December (41.2°F).
- Average low temperature in September: 53.8°F
The month with the highest average low temperature is July (61.7°F).
The coldest month (with the lowest average low temperature) is December (21.9°F).
Average pressure in September
Derby, CO
- Average pressure in September: 30"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The months with the lowest atmospheric pressure are April and June (29.91"Hg).
Average wind speed in September
Derby, CO
- Average wind speed in September: 5.9mph
The windiest month (with the highest average wind speed) is April (6.9mph).
The calmest month (with the lowest average wind speed) is December (5.8mph).
Average humidity in September
Derby, CO
- Average humidity in September: 41%
The month with the highest relative humidity is February (64%).
The month with the lowest relative humidity is August (39%).
Average rainfall in September
Derby, CO
- Average rainfall in September: 0.16"
The wettest month (with the highest rainfall) is July (0.59").
The driest months (with the least rainfall) are January and December (0.08").
Average rainfall days in September
Derby, CO
- Average rainfall days in September: 3.3 days
The month with the highest number of rainy days is July (8.2 days).
The month with the least rainy days is February (1.2 days).
Average snowfall in September
Derby, CO
- Average snowfall in September: 0"
The month with the highest snowfall is October (1.42").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Derby, CO
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (4.7 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in September /
Average sunshine in September
Derby, CO
- Average daylight in September: 12h and 2min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 24min).
- Average sunshine in September: 11h and 1min
The months with the most sunshine are June and July (Average sunshine: 11h and 54min).
The month with the least sunshine is February (Average sunshine: 6h and 42min).
Average sunshine days in September
Derby, CO
- Average sunshine days in September: 24.5 days
The month with the most sunshine days is December (28.5 days).
The month with the least sunshine days is July (19.6 days).
Average UV index in September
Derby, CO
- Average UV index in September: 5
The months with the highest UV index are June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Derby, CO
- Average cloud cover in September: 14
The months with the most cloud cover are February, April and May (Cloud cover 25).
The month with the least cloud cover is September (Cloud cover 14).
Average visibility in September
Derby, CO
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Derby, Colorado, USA
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