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
As Royal City enters September, the average high-temperature decreases from the a hot 88.3°F (31.3°C) of August to a warm 76.1°F (24.5°C). Royal City reports an average nighttime low-temperature of 54.7°F (12.6°C) in September.Humidity
In September, the average relative humidity is 45%.Rainfall
In Royal City, during September, the rain falls for 4.1 days and regularly aggregates up to 0.31" (8mm) of precipitation. In Royal City, Washington, during the entire year, the rain falls for 86.4 days and collects up to 6.38" (162mm) of precipitation.Snowfall
Months with snowfall in Royal City, Washington, are January through April, September, November and December. 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 22.3 snowfall days, and 10" (254mm) of snow is accumulated.Daylight
In Royal City, the average length of the day in September is 12h and 32min.On the first day of the month, sunrise is at 6:19 am and sunset at 7:37 pm. On the last day of September, sunrise is at 6:57 am and sunset at 6:39 pm PDT.
Sunshine
In Royal City, the average sunshine in September is 10.8h.UV index
In September, the average daily maximum UV index is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for average individuals.Note: In September, a regular UV index of 4 translates into these guidelines:
Safety measures are advised. Light-skinned individuals may experience burns in under half an hour. Avoiding direct sunlight during midday hours helps reduce the risk from intense UV radiation. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear. Be informed! The Sun's UV radiation can be nearly doubled due to the reflection from snow.
Frequently asked questions
What are September temperatures in Royal City?
What is the average humidity in September in Royal City?
How many days does it rain in September in Royal City?
When does it start snowing in Royal City?
How many hours of daylight does Royal City have in September?
What time are sunrise and sunset in September in Royal City?
How long on average sun shines in September in Royal City?
What is the UV index reading in September in Royal City?
Average temperature in September
Royal City, WA
- Average high temperature in September: 76.1°F
The warmest months (with the highest average high temperature) are July and August (88.3°F).
The month with the lowest average high temperature is December (34.5°F).
- Average low temperature in September: 54.7°F
The month with the highest average low temperature is August (61.5°F).
The coldest month (with the lowest average low temperature) is December (24.3°F).
Average pressure in September
Royal City, WA
- Average pressure in September: 29.96"Hg
The month with the highest atmospheric pressure is January (30.17"Hg).
The month with the lowest atmospheric pressure is August (29.91"Hg).
Average wind speed in September
Royal City, WA
- Average wind speed in September: 6.3mph
The windiest month (with the highest average wind speed) is April (7.6mph).
The calmest month (with the lowest average wind speed) is December (4.7mph).
Average humidity in September
Royal City, WA
- Average humidity in September: 45%
The month with the highest relative humidity is January (83%).
The month with the lowest relative humidity is July (37%).
Average rainfall in September
Royal City, WA
- Average rainfall in September: 0.31"
The wettest months (with the highest rainfall) are January and December (0.87").
The driest month (with the least rainfall) is August (0.2").
Average rainfall days in September
Royal City, WA
- Average rainfall days in September: 4.1 days
The month with the highest number of rainy days is March (10.6 days).
The month with the least rainy days is August (3.5 days).
Average snowfall in September
Royal City, WA
- Average snowfall in September: 0.04"
The month with the highest snowfall is December (3.43").
The months with the least snowfall are May, June, July, August and October (0").
Average snowfall days in September
Royal City, WA
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is December (6.5 days).
The months with the least snowfall days are May, June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Royal City, WA
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 48min).
The month with the shortest days is December (Average daylight: 8h and 36min).
- Average sunshine in September: 10h and 5min
The months with the most sunshine are July and August (Average sunshine: 12h and 0min).
The month with the least sunshine is January (Average sunshine: 4h and 54min).
Average sunshine days in September
Royal City, WA
- Average sunshine days in September: 24.3 days
The months with the most sunshine days are July and August (25.8 days).
The month with the least sunshine days is February (16 days).
Average UV index in September
Royal City, WA
- 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
Royal City, WA
- Average cloud cover in September: 16
The month with the most cloud cover is January (Cloud cover 47).
The months with the least cloud cover are July and August (Cloud cover 10).
Average visibility in September
Royal City, WA
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January and December (5mi).
Royal City, Washington, USA
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