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 arrival of September corresponds with a shift in temperature, down from a warm 75.9°F (24.4°C) in August to an enjoyable 64.6°F (18.1°C). A pronounced dip becomes evident during the nights in September as Winthrop logs a consistent average temperature of 41.2°F (5.1°C).Humidity
The average relative humidity in September is 62%.Rainfall
In September, the rain falls for 9.7 days. Throughout September, 0.98" (25mm) of precipitation is accumulated. In Winthrop, during the entire year, the rain falls for 142.6 days and collects up to 17.91" (455mm) 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 0.2 snowfall days, it receives 0.2" (5mm) of snow. In Winthrop, during the entire year, snow falls for 66.9 days and aggregates up to 43.98" (1117mm) of snow.Daylight
In September, the average length of the day is 12h and 34min.On the first day of September, sunrise is at 6:19 am and sunset at 7:41 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 10.6h.UV index
In Winthrop, the average daily maximum UV index in September is 3. A UV Index of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV radiation for the ordinary person.Note: An average maximum UV index of 3 in September leads to these recommendations:
Ensure safety - Recommendations to avert sunburn are presented. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Employ a wide-brim hat for potent defense against up to 50% of UV rays. Take note! UV radiation from the Sun can double in intensity due to snow reflection.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What is the usual temperature for Winthrop in September?
What is the average humidity in September?
How many days does it rain in September?
When does it start to snow?
How many hours of daylight does Winthrop have in September?
When is the sunrise / sunset in September?
How long on average sun shines in September?
How high is the UV index in September?
Average temperature in September
Winthrop, WA
- Average high temperature in September: 64.6°F
The warmest month (with the highest average high temperature) is August (75.9°F).
The month with the lowest average high temperature is December (27.5°F).
- Average low temperature in September: 41.2°F
The month with the highest average low temperature is August (47.8°F).
The coldest month (with the lowest average low temperature) is December (13.5°F).
Average pressure in September
Winthrop, WA
- Average pressure in September: 29.98"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The months with the lowest atmospheric pressure are June and August (29.95"Hg).
Average wind speed in September
Winthrop, WA
- Average wind speed in September: 4.6mph
The windiest months (with the highest average wind speed) are June and July (5mph).
The calmest months (with the lowest average wind speed) are January and December (3.6mph).
Average humidity in September
Winthrop, WA
- Average humidity in September: 62%
The month with the highest relative humidity is January (93%).
The months with the lowest relative humidity are July and August (53%).
Average rainfall in September
Winthrop, WA
- Average rainfall in September: 0.98"
The wettest month (with the highest rainfall) is December (2.48").
The driest month (with the least rainfall) is July (0.31").
Average rainfall days in September
Winthrop, WA
- Average rainfall days in September: 9.7 days
The month with the highest number of rainy days is March (17.3 days).
The month with the least rainy days is August (6.1 days).
Average snowfall in September
Winthrop, WA
- Average snowfall in September: 0.2"
The month with the highest snowfall is December (12.87").
The months with the least snowfall are May, June, July and August (0").
Average snowfall days in September
Winthrop, WA
- Average snowfall days in September: 0.2 days
The month with the highest number of snowfall days is December (15.3 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in September /
Average sunshine in September
Winthrop, WA
- Average daylight in September: 12h and 4min
The month with the longest days is June (Average daylight: 16h and 6min).
The month with the shortest days is December (Average daylight: 8h and 24min).
- Average sunshine in September: 10h and 4min
The month with the most sunshine is August (Average sunshine: 11h and 54min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).
Average sunshine days in September
Winthrop, WA
- Average sunshine days in September: 18.1 days
The month with the most sunshine days is August (23 days).
The month with the least sunshine days is March (8.3 days).
Average UV index in September
Winthrop, WA
- Average UV index in September: 3
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February and November (UV index 1).
Average cloud cover in September
Winthrop, WA
- Average cloud cover in September: 23
The month with the most cloud cover is January (Cloud cover 55).
The month with the least cloud cover is August (Cloud cover 15).
Average visibility in September
Winthrop, WA
- Average visibility in September: 6mi
The months with the highest visibility are May, June, July, August, September and October (6mi).
The months with the lowest visibility are January and February (3mi).
Winthrop, Washington, USA
Weather forecast for your location
2. Allow the app to use your location