Weathermondo.com
United StatesThe weather in September in Union
It's pleasantly warm in September in Union with an average temperature of 22°C. Temperatures this month range from a low of 19°C to a high of 26°C. At night, you can expect temperatures between 8°C and 13°C.
Looking for great weather? September is a good time to be in Union. The temperatures are nice, and there’s not too much rain.
Average temperatures and precipitation
This chart shows the average daily maximum and minimum temperatures (in degrees Celsius) and precipitation (in millimeters) in September for Union, Washington. A low precipitation value usually indicates little to no rainfall on that day in recent years, while a higher value suggests more frequent rainfall.
Temperature records
With 34°C in 2017, Union reached the highest temperature in September over the past 10 years. The lowest daytime temperature in this month was 12°C in 2021. The extreme nighttime temperatures ranged from a lowest recorded value of 1°C to a highest value of 17°C.
Rainfall amount
In September, there is an average of 78 mm of precipitation, spread over 10 days. The wind speed is around 3 Bft, mostly coming from the South.
Daily weather in September for Union
Click on any day in September to get detailed info about the usual weather on that day in Union. Check out the historical temperatures and precipitation over the past 10 years on this day.
September weather comparison
| Union | New York | |
|---|---|---|
| Average temperature | 22°C | 27°C |
| Max. temperature | 26°C | 31°C |
| Min. temperature | 8°C | -5°C |
| Total precipitation | 78 mm | 57 mm |
| Rainy days | 10 days | 9 days |
Start of September
The month of September starts in Union with warm temps, averaging around 25°C during the day and nights around 12°C.
Mid September
By mid-September, daytime temps drop to around 22°C, with nights around 11°C. There’s a chance of some showers during this time, but plenty of dry and sunny days too.
End of September
By the end of September, the average daytime temperature in Union is around 21°C, while nighttime temps are about 10°C. A shower might pop up, but overall, the weather will be dry and sunny.
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UV index
The UV index is a maximum of 5 this month. That's a moderate value on the intensity scale of 1 to 11. Unprotected skin can burn in about 30 minutes.
Check out the climate of Union for all months and discover the best travel time
Temperature charts
These charts show the average temperatures in September in Union, Washington. The temperatures are shown in degrees Celsius and are calculated based on data from the past 10 years.
Daily Temperature in September in Union
Temperature in September in Union over the years
Precipitation charts
These charts show the average amount of precipitation in September in Union, Washington. Precipitation is always measured as water, even when it falls as snow or hail The amount of precipitation is displayed in millimeters, while snowfall is shown in centimeters.
Daily Precipitation in September in Union
Total precipitation in September in Union over the years
Daily UV index in September in Union
This chart shows the average daily UV index in September in Union, with the UV index ranging from 0 to a maximum of 11. The bottom of the chart shows the days of the month. Based on historical data, this chart provides an idea of the daily UV radiation levels you can expect.
Weather experiences in September in Union
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Average weather in Union by month
Click on a month below to see detailed weather info for Union. Based on historical weather data, you can see the average temperature, precipitation, wind, and UV index for each day of the month.