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
The transition into September is accompanied by a temperature decrease, with the average high-temperature shifting from a hot 89.4°F (31.9°C) in August to a warm 78.6°F (25.9°C). In September, the average low-temperature in Richland records at a mild 57°F (13.9°C) during the nights.Humidity
In September, the average relative humidity in Richland is 43%.Rainfall
July and September are months with the least rain when the rain falls for 4 days and typically aggregates up to 0.2" (5mm) of rain.Snowfall
April through October are months without snowfall.Daylight
In Richland, the average length of the day in September is 12h and 32min.On the first day of September, sunrise is at 6:18 am and sunset at 7:35 pm. On the last day of the month, sunrise is at 6:55 am and sunset at 6:38 pm PDT.
Sunshine
The average sunshine in September is 10.9h.UV index
The average daily maximum UV index in September is 5. A UV Index estimate of 3 to 5 represents a moderate health risk from exposure to the Sun's UV rays for the average person.Note: The daily high UV index of 5 during September translates into the following recommendations:
Be vigilant - A duty to shield skin and eyes from injury exists. To avoid the Sun's strongest rays, limit exposure around the mid-day period. For effective sun eye protection, rely on sunglasses certified for UVA and UVB resistance.
Frequently asked questions
What are September temperatures in Richland?
What is the average humidity in September in Richland?
What is the driest month in Richland?
How much does it rain in Richland in September?
When it does not snow in Richland?
How many hours of daylight does Richland have in September?
When are sunrise and sunset in September in Richland?
How many hours of sunshine does Richland have in September?
What is the UV index intensity in September in Richland?
Average temperature in September
Richland, WA
- Average high temperature in September: 78.6°F
The warmest month (with the highest average high temperature) is July (90.1°F).
The month with the lowest average high temperature is December (38.1°F).
- Average low temperature in September: 57°F
The month with the highest average low temperature is August (64.2°F).
The coldest month (with the lowest average low temperature) is December (27.5°F).
Average pressure in September
Richland, WA
- Average pressure in September: 29.95"Hg
The month with the highest atmospheric pressure is January (30.18"Hg).
The month with the lowest atmospheric pressure is August (29.91"Hg).
Average wind speed in September
Richland, WA
- Average wind speed in September: 6.6mph
The windiest month (with the highest average wind speed) is April (8.3mph).
The calmest month (with the lowest average wind speed) is December (5.6mph).
Average humidity in September
Richland, WA
- Average humidity in September: 43%
The month with the highest relative humidity is January (81%).
The month with the lowest relative humidity is July (35%).
Average rainfall in September
Richland, WA
- Average rainfall in September: 0.2"
The wettest month (with the highest rainfall) is December (0.94").
The driest months (with the least rainfall) are July and September (0.2").
Average rainfall days in September
Richland, WA
- Average rainfall days in September: 4 days
The month with the highest number of rainy days is March (12.3 days).
The month with the least rainy days is July (3.5 days).
Average snowfall in September
Richland, WA
- Average snowfall in September: 0"
The month with the highest snowfall is February (2.2").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Richland, WA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is December (3.3 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Richland, WA
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 42min).
The month with the shortest days is December (Average daylight: 8h and 42min).
- Average sunshine in September: 10h and 5min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is January (Average sunshine: 5h and 24min).
Average sunshine days in September
Richland, WA
- Average sunshine days in September: 24.2 days
The month with the most sunshine days is July (25.7 days).
The months with the least sunshine days are February and March (15.3 days).
Average UV index in September
Richland, WA
- Average UV index in September: 5
The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Richland, WA
- Average cloud cover in September: 16
The month with the most cloud cover is January (Cloud cover 44).
The month with the least cloud cover is July (Cloud cover 9).
Average visibility in September
Richland, WA
- 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).
Richland, Washington, USA
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