September weather forecastMountain View, CO
September
Weather in September
September, the first month of the autumn in Mountain View, is still a warm month, with an average temperature ranging between max 76.6°F (24.8°C) and min 51.4°F (10.8°C).Temperature
In Mountain View, the average high-temperature in September slightly decreases from 83.8°F (28.8°C) in August to a still moderately hot 76.6°F (24.8°C). Mountain View documents a significant temperature variance in September, with the mean nighttime lows settling at a cool 51.4°F (10.8°C).Humidity
In September, the average relative humidity in Mountain View is 42%.Rainfall
In Mountain View, in September, it is raining for 7.6 days, with typically 0.51" (13mm) of accumulated precipitation. In Mountain View, Colorado, during the entire year, the rain falls for 95 days and collects up to 10.08" (256mm) of precipitation.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 September, sunrise is at 6:29 am and sunset at 7:30 pm. On the last day of the month, sunrise is at 6:56 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 in Mountain View is 5. A UV Index value of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for average individuals.Note: In September, the average maximum UV index of 5 translates into the following recommendations:
Be vigilant - Preventing sunburn is recommended. Sun's radiation is most powerful around mid-day, so it's best to limit outdoor activities during this time. It's wise to wear UVA and UVB-blocking sunglasses when the sun shines brightly. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Mountain View, CO
- Average high temperature in September: 76.6°F
The warmest month (with the highest average high temperature) is July (85.1°F).
The month with the lowest average high temperature is December (39.6°F).
- Average low temperature in September: 51.4°F
The month with the highest average low temperature is July (59.5°F).
The coldest months (with the lowest average low temperature) are February and December (20.7°F).
Average pressure in September
Mountain View, CO
- Average pressure in September: 30.01"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
Mountain View, CO
- Average wind speed in September: 5.6mph
The windiest months (with the highest average wind speed) are March and April (6.5mph).
The calmest month (with the lowest average wind speed) is September (5.6mph).
Average humidity in September
Mountain View, CO
- Average humidity in September: 42%
The month with the highest relative humidity is February (66%).
The months with the lowest relative humidity are June and August (41%).
Average rainfall in September
Mountain View, CO
- Average rainfall in September: 0.51"
The wettest month (with the highest rainfall) is May (1.69").
The driest month (with the least rainfall) is January (0.35").
Average rainfall days in September
Mountain View, CO
- Average rainfall days in September: 7.6 days
The month with the highest number of rainy days is May (14.1 days).
The month with the least rainy days is November (3.3 days).
Average snowfall in September
Mountain View, CO
- Average snowfall in September: 0"
The month with the highest snowfall is February (5.83").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in September
Mountain View, CO
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is February (8.6 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Mountain View, CO
- Average daylight in September: 12h and 24min
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: 11h and 6min
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 48min).
Average sunshine days in September
Mountain View, CO
- Average sunshine days in September: 19 days
The month with the most sunshine days is November (23.9 days).
The month with the least sunshine days is July (13.5 days).
Average UV index in September
Mountain View, 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
Mountain View, CO
- Average cloud cover in September: 14
The month with the most cloud cover is April (Cloud cover 25).
The month with the least cloud cover is September (Cloud cover 14).
Average visibility in September
Mountain View, 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).
