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's arrival signals a moderate reduction in the average high-temperature, easing from 81.1°F (27.3°C) in August to a still warm 75.6°F (24.2°C). During September nights, Washington witnesses a consistent average temperature of 56.3°F (13.5°C).Humidity
In September, the average relative humidity is 76%.Rainfall
In Washington, in September, during 9.5 rainfall days, 1.65" (42mm) of precipitation is typically accumulated. In Washington, during the entire year, the rain falls for 123.7 days and collects up to 18.94" (481mm) of precipitation.Snowfall
In Washington, snow does not fall in May through September.Daylight
In Washington, Iowa, the average length of the day in September is 12h and 28min.On the first day of September in Washington, sunrise is at 6:33 am and sunset at 7:39 pm. On the last day of the month, sunrise is at 7:03 am and sunset at 6:49 pm CDT.
Sunshine
In September, the average sunshine is 9.5h.UV index
The average daily maximum UV index in September in Washington, Iowa, is 4. A UV Index reading of 3 to 5 represents a moderate health risk from exposure to the Sun's UV rays for the ordinary person.Note: In September, a daily UV index of 4 turns into the following recommendations:
Exercise caution. Those with pale skin may experience burns in less than half an hour. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. Prioritize a wide-brim hat for comprehensive sun defense for your face, neck, eyes, and ears.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures in Washington?
What is the average humidity in September in Washington?
How much does it rain in Washington in September?
When it does not snow in Washington?
Does it snow in Washington in September?
How many hours of daylight does Washington have in September?
What time are sunrise and sunset in September in Washington?
How many hours of sunshine does Washington have in September?
How high is the UV index in September in Washington?
Average temperature in September
Washington, IA
- Average high temperature in September: 75.6°F
The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (28.8°F).
- Average low temperature in September: 56.3°F
The month with the highest average low temperature is July (65.1°F).
The coldest month (with the lowest average low temperature) is January (16.5°F).
Average pressure in September
Washington, 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
Washington, IA
- Average wind speed in September: 7.9mph
The windiest month (with the highest average wind speed) is January (10.7mph).
The calmest month (with the lowest average wind speed) is August (6.8mph).
Average humidity in September
Washington, IA
- Average humidity in September: 76%
The months with the highest relative humidity are January and July (83%).
The month with the lowest relative humidity is October (72%).
Average rainfall in September
Washington, IA
- Average rainfall in September: 1.65"
The wettest month (with the highest rainfall) is May (2.91").
The driest month (with the least rainfall) is December (0.71").
Average rainfall days in September
Washington, IA
- Average rainfall days in September: 9.5 days
The month with the highest number of rainy days is May (17 days).
The month with the least rainy days is February (4.2 days).
Average snowfall in September
Washington, IA
- Average snowfall in September: 0"
The month with the highest snowfall is January (2.52").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in September
Washington, IA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is January (8.9 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
Washington, IA
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in September: 9h and 3min
The month with the most sunshine is July (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 4h and 12min).
Average sunshine days in September
Washington, IA
- Average sunshine days in September: 18.1 days
The month with the most sunshine days is December (20.5 days).
The month with the least sunshine days is May (10.9 days).
Average UV index in September
Washington, IA
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in September
Washington, IA
- Average cloud cover in September: 29
The month with the most cloud cover is January (Cloud cover 55).
The months with the least cloud cover are August and September (Cloud cover 29).
Average visibility in September
Washington, 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).
Washington, Iowa, USA
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