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 suggests a modest reduction in the average high-temperature, shifting from a warm 81.9°F (27.7°C) in August to a pleasant 70.5°F (21.4°C). In Waterville, the nighttime temperature averages to a chilly 49.1°F (9.5°C) during September.Humidity
In Waterville, the average relative humidity in September is 52%.Rainfall
In September, the rain falls for 6.7 days. Throughout September, 0.55" (14mm) of precipitation is accumulated. In Waterville, during the entire year, the rain falls for 99.9 days and collects up to 10.47" (266mm) of precipitation.Snowfall
Months with snowfall are January through April, September through December. September is the first month it typically snows. Throughout September, in the average 0.3 snowfall days, it receives 0.71" (18mm) of snow. In Waterville, during the entire year, snow falls for 48.7 days and aggregates up to 28.62" (727mm) of snow.Daylight
In Waterville, the average length of the day in September is 12h and 33min.On the first day of September, sunrise is at 6:20 am and sunset at 7:40 pm. On the last day of the month, sunrise is at 6:59 am and sunset at 6:40 pm PDT.
Sunshine
In September, the average sunshine is 10.7h.UV index
In September, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a medium vulnerability from unprotected exposure to Sun's UV rays for average individuals.Note: The maximum UV index of 4 during September translates into these guidelines:
Take precautions - Protection against sun damage is advised. The Sun is at its harshest during midday; protect yourself by staying in shaded areas and minimizing exposure. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes. Remember! The Sun's UV radiation can be magnified almost twofold by the reflection of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the average September temperature?
What is the average humidity in September?
How much does it rain in September?
When does it start snowing?
What is the average length of the day in September?
What time are sunrise and sunset in September in Waterville?
How long on average sun shines in September?
What is the UV index reading in September?
Average temperature in September
Waterville, WA
- Average high temperature in September: 70.5°F
The warmest month (with the highest average high temperature) is July (82.2°F).
The month with the lowest average high temperature is December (30.2°F).
- Average low temperature in September: 49.1°F
The month with the highest average low temperature is August (55.8°F).
The coldest months (with the lowest average low temperature) are January and December (19°F).
Average pressure in September
Waterville, WA
- Average pressure in September: 29.97"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is August (29.93"Hg).
Average wind speed in September
Waterville, WA
- Average wind speed in September: 5.3mph
The windiest month (with the highest average wind speed) is June (6.1mph).
The calmest months (with the lowest average wind speed) are January and December (3.5mph).
Average humidity in September
Waterville, WA
- Average humidity in September: 52%
The month with the highest relative humidity is January (90%).
The months with the lowest relative humidity are July and August (43%).
Average rainfall in September
Waterville, WA
- Average rainfall in September: 0.55"
The wettest month (with the highest rainfall) is December (1.65").
The driest month (with the least rainfall) is July (0.16").
Average rainfall days in September
Waterville, WA
- Average rainfall days in September: 6.7 days
The month with the highest number of rainy days is March (12.8 days).
The month with the least rainy days is August (3.8 days).
Average snowfall in September
Waterville, WA
- Average snowfall in September: 0.71"
The month with the highest snowfall is December (9.06").
The months with the least snowfall are May, June, July and August (0").
Average snowfall days in September
Waterville, WA
- Average snowfall days in September: 0.3 days
The month with the highest number of snowfall days is January (12 days).
The months with the least snowfall days are May, June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Waterville, WA
- Average daylight in September: 12h and 3min
The month with the longest days is June (Average daylight: 15h and 54min).
The month with the shortest days is December (Average daylight: 8h and 30min).
- Average sunshine in September: 10h and 4min
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 6min).
Average sunshine days in September
Waterville, WA
- Average sunshine days in September: 21.7 days
The month with the most sunshine days is July (25.7 days).
The month with the least sunshine days is March (13.2 days).
Average UV index in September
Waterville, WA
- Average UV index in September: 4
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).
Average cloud cover in September
Waterville, WA
- Average cloud cover in September: 19
The month with the most cloud cover is January (Cloud cover 54).
The months with the least cloud cover are July and August (Cloud cover 12).
Average visibility in September
Waterville, WA
- Average visibility in September: 6mi
The months with the highest visibility are April, May, June, July, August, September and October (6mi).
The months with the lowest visibility are January, February and December (4mi).
Waterville, Washington, USA
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