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
Hermiston's September weather shows a moderate shift in high-temperatures, falling from August's hot 87.1°F (30.6°C) to a warm 76.1°F (24.5°C). During September, the average low-temperature is a refreshing 57°F (13.9°C).Humidity
In September, the average relative humidity is 44%.Rainfall
In Hermiston, in September, during 5.1 rainfall days, 0.31" (8mm) of precipitation is typically accumulated. Throughout the year, there are 109.3 rainfall days, and 8.11" (206mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through March, September, November and December. September is the first month it typically snows. Throughout September, in the average 0.1 snowfall days, it receives 0.08" (2mm) of snow. Throughout the year, there are 12 snowfall days, and 6.06" (154mm) of snow is accumulated.Daylight
In Hermiston, the average length of the day in September is 12h and 31min.On the first day of September, sunrise is at 6:19 am and sunset at 7:34 pm. On the last day of the month, sunrise is at 6:55 am and sunset at 6:38 pm PDT.
Sunshine
In Hermiston, the average sunshine in September is 10.7h.UV index
The average daily maximum UV index in September is 4. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for the average person.Note: In September, the average maximum UV index of 4 translates into the following recommendations:
Exercise prudence. Persons with fair skin could be burned in under 30 minutes. To prevent harmful UV exposure, minimize direct contact with the Sun around midday. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses. Be prepared! The intensity of the Sun's UV radiation can be amplified nearly double due to snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are September temperatures in Hermiston?
What is the average humidity in September?
How many days does it rain in September?
When does it start to snow in Hermiston?
What is the average length of the day in September?
What time are sunrise and sunset in September in Hermiston?
How many hours of sunshine does Hermiston have in September?
What is the UV index reading in September?
Average temperature in September
Hermiston, OR
- Average high temperature in September: 76.1°F
The warmest month (with the highest average high temperature) is July (88°F).
The month with the lowest average high temperature is December (38.8°F).
- Average low temperature in September: 57°F
The month with the highest average low temperature is August (64°F).
The coldest month (with the lowest average low temperature) is December (28.6°F).
Average pressure in September
Hermiston, OR
- Average pressure in September: 29.96"Hg
The month with the highest atmospheric pressure is January (30.19"Hg).
The month with the lowest atmospheric pressure is August (29.91"Hg).
Average wind speed in September
Hermiston, OR
- Average wind speed in September: 7.1mph
The windiest month (with the highest average wind speed) is April (9.2mph).
The calmest month (with the lowest average wind speed) is December (6.1mph).
Average humidity in September
Hermiston, OR
- Average humidity in September: 44%
The month with the highest relative humidity is January (79%).
The months with the lowest relative humidity are July and August (36%).
Average rainfall in September
Hermiston, OR
- Average rainfall in September: 0.31"
The wettest months (with the highest rainfall) are March and December (1.06").
The driest month (with the least rainfall) is July (0.16").
Average rainfall days in September
Hermiston, OR
- Average rainfall days in September: 5.1 days
The month with the highest number of rainy days is March (14.5 days).
The month with the least rainy days is August (3.3 days).
Average snowfall in September
Hermiston, OR
- Average snowfall in September: 0.08"
The month with the highest snowfall is February (2.72").
The months with the least snowfall are April, May, June, July, August and October (0").
Average snowfall days in September
Hermiston, OR
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is December (3.7 days).
The months with the least snowfall days are April, May, June, July, August and October (0 days).
Average daylight in September /
Average sunshine in September
Hermiston, OR
- 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 4min
The month with the most sunshine is August (Average sunshine: 12h and 6min).
The months with the least sunshine are January and December (Average sunshine: 5h and 30min).
Average sunshine days in September
Hermiston, OR
- Average sunshine days in September: 23.2 days
The month with the most sunshine days is July (25.5 days).
The month with the least sunshine days is February (13.3 days).
Average UV index in September
Hermiston, OR
- Average UV index in September: 4
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
Hermiston, OR
- Average cloud cover in September: 16
The months with the most cloud cover are January and December (Cloud cover 43).
The months with the least cloud cover are July and August (Cloud cover 9).
Average visibility in September
Hermiston, OR
- 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).
Hermiston, Oregon, USA
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