September weather forecast
Richland, WA

Weather in September

September, the first month of the autumn in Richland, is also a moderately hot month, with an average temperature ranging between max 78.6°F (25.9°C) and min 57°F (13.9°C).

Temperature

In September, the average high-temperature decreases from a tropical 89.4°F (31.9°C) in August to a moderately hot 78.6°F (25.9°C). In September, the average low-temperature is 57°F (13.9°C).

Humidity

The average relative humidity in September in Richland is 43%.

Rainfall

July and September are months with the least rain in Richland when the rain falls for 4 days and typically aggregates up to 0.2" (5mm) of rain.

Snowfall

In Richland, snow does not fall in April through October.

Daylight

In September, the average length of the day in Richland is 12h and 32min.
On the first day of September, sunrise is at 6:17 am and sunset at 7:36 pm. On the last day of the month, sunrise is at 6:54 am and sunset at 6:39 pm PDT.

Sunshine

In September, the average sunshine is 10.9h.

UV index

The average daily maximum UV index in September is 5. A UV Index reading of 3 to 5 represents a medium vulnerability from exposure to the Sun's UV rays for the average person.
Note: The average daily UV index of 5 in September transform into the following instructions:
Take precautions - Protection against skin and eye damage is obliged. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. On bright days sunglasses that block both UVA and UVB rays should be worn. A hat with a wide brim is extremely helpful, as it can prevent roughly 50% of UV radiation from reaching the eyes.
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FAQ

What is the temperature in September in Richland?

In Richland, in September, the average high-temperature is 78.6°F (25.9°C), and the average low-temperature is 57°F (13.9°C).

What is the average humidity in September in Richland?

In September, the average relative humidity in Richland, Washington, is 43%.

What is the driest month in Richland?

The months with the least rainfall in Richland are July and September Rain falls for 4 days and accumulates 0.2" (5mm) of rain.

How many days does it rain in September in Richland?

In September, in Richland, Washington, the rain falls for 4 days. Throughout September, 0.2" (5mm) of precipitation is accumulated.

When it does not snow in Richland?

April through October are months without snowfall.

What is the average length of the day in September in Richland?

In September, the average day length is 12h and 32min.

What time are sunrise and sunset in September in Richland?

On the first day of September in Richland, Washington, sunrise is at 6:17 am and sunset at 7:36 pm. On the last day of the month, sunrise is at 6:54 am and sunset at 6:39 pm PDT.

How many hours of sunshine does Richland have in September?

In Richland, Washington, the average sunshine duration in September is 10.9h.

What is the UV index intensity in September in Richland?

In Richland, Washington, the average daily maximum UV index in September is 5. A UV Index value of 3 to 5 symbolizes a moderate vulnerability from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in September
Richland, WA

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).

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Average pressure in September
Richland, WA

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).

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Average wind speed in September
Richland, WA

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).

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Average humidity in September
Richland, WA

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%).

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Average rainfall in September
Richland, WA

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").

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Average rainfall days in September
Richland, WA

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).

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Average snowfall in September
Richland, WA

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").

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Average snowfall days in September
Richland, WA

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).

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Average daylight in September /
Average sunshine in September
Richland, WA

Average daylight in September / Average sunshine in September - Richland, WA
  • Average daylight in September: 12h and 32min

The month with the longest days is June (Average daylight: 15h and 44min).
The month with the shortest days is December (Average daylight: 8h and 41min).

  • Average sunshine in September: 10h and 54min

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).

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Average sunshine days in September
Richland, WA

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).

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Average UV index in September
Richland, WA

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).

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Average cloud cover in September
Richland, WA

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).

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Average visibility in September
Richland, WA

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).

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