September weather forecastWashington, MO
September
Weather in September
The first month of the autumn, September, is also a moderately hot month in Washington, Missouri, with an average temperature fluctuating between 80.1°F (26.7°C) and 59.2°F (15.1°C).Temperature
With September's onset, the weather reveals a slight temperature decrease, transitioning from a hot 87.1°F (30.6°C) in August to a warm 80.1°F (26.7°C). Washington experiences an average low-temperature reading of 59.2°F (15.1°C) throughout September.Humidity
The average relative humidity in September is 74%.Rainfall
In Washington, in September, during 11 rainfall days, 1.89" (48mm) of precipitation is typically accumulated. In Washington, Missouri, during the entire year, the rain falls for 133.1 days and collects up to 27.24" (692mm) of precipitation.Snowfall
January through March, September, November and December are months with snowfall. September is the first month it typically snows. Throughout September, in the average 0.1 snowfall days, it receives 0.04" (1mm) of snow. Throughout the year, there are 16.6 snowfall days, and 5.87" (149mm) of snow is accumulated.Daylight
The average length of the day in September is 12h and 25min.On the first day of the month, sunrise is at 6:34 am and sunset at 7:33 pm. On the last day of September, sunrise is at 6:59 am and sunset at 6:47 pm CDT.
Sunshine
In September, the average sunshine is 9.4h.UV index
In September, the average daily maximum UV index is 5. A UV Index estimate of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV radiation for the ordinary person.Note: The UV index of 5 during September leads to these advisories:
Make use of precautions - Suggestions to resist sunburn are communicated. Sun exposure should be minimized, especially during midday, to avoid harmful UV radiation. Employ a wide-brim hat for potent defense against up to 50% of UV rays. Note well! The intensity of the Sun's UV rays can be nearly doubled by snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Washington, MO
- Average high temperature in September: 80.1°F
The warmest month (with the highest average high temperature) is July (88.3°F).
The month with the lowest average high temperature is January (38.1°F).
- Average low temperature in September: 59.2°F
The month with the highest average low temperature is July (68.2°F).
The coldest month (with the lowest average low temperature) is January (24.1°F).
Average pressure in September
Washington, MO
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in September
Washington, MO
- Average wind speed in September: 5.7mph
The windiest month (with the highest average wind speed) is January (8.5mph).
The calmest month (with the lowest average wind speed) is August (5.3mph).
Average humidity in September
Washington, MO
- Average humidity in September: 74%
The month with the highest relative humidity is May (78%).
The month with the lowest relative humidity is October (72%).
Average rainfall in September
Washington, MO
- Average rainfall in September: 1.89"
The wettest months (with the highest rainfall) are April and May (3.23").
The driest month (with the least rainfall) is February (1.42").
Average rainfall days in September
Washington, MO
- Average rainfall days in September: 11 days
The month with the highest number of rainy days is May (16.3 days).
The month with the least rainy days is January (6.2 days).
Average snowfall in September
Washington, MO
- Average snowfall in September: 0.04"
The month with the highest snowfall is February (2.09").
The months with the least snowfall are April, May, June, July, August and October (0").
Average snowfall days in September
Washington, MO
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is January (5.1 days).
The months with the least snowfall days are May, June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Washington, MO
- Average daylight in September: 12h and 24min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in September: 9h and 24min
The months with the most sunshine are June and July (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 36min).
Average sunshine days in September
Washington, MO
- Average sunshine days in September: 17 days
The month with the most sunshine days is December (20.6 days).
The month with the least sunshine days is May (12.8 days).
Average UV index in September
Washington, MO
- 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
Washington, MO
- Average cloud cover in September: 32
The months with the most cloud cover are January and February (Cloud cover 50).
The months with the least cloud cover are June, July and August (Cloud cover 30).
Average visibility in September
Washington, MO
- Average visibility in September: 6mi
The months with the highest visibility are January, February, March, April, June, July, September, October, November and December (6mi).
The months with the lowest visibility are May and August (5mi).
