September weather forecastYakima, WA
September
Weather in September
With September comes the first whispers of fall in Yakima's weather. Temperatures cool down from the highs of summer, but the conditions remain pleasant and inviting. Despite the fresher temperatures, the sunshine hours still remain high at 11.1 hours, allowing outdoor activities to continue in full swing. As autumn's whispers slowly become a steady murmur, Yakima preps itself to bid goodbye to another summer. This shifting phase carries an enchanting beauty, manifesting more prominently with each passing day of September.Temperature
A decrease in the average high-temperature is observed during September, shifting from a tropical 86.5°F (30.3°C) in August to a moderately hot 74.8°F (23.8°C). September brings Yakima a consistent average low-temperature of 53.4°F (11.9°C).Humidity
The average relative humidity in September is 48%.Rainfall
In Yakima, in September, it is raining for 3.9 days, with typically 0.24" (6mm) of accumulated precipitation. Throughout the year, there are 82.2 rainfall days, and 5.43" (138mm) 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 0.04" (1mm) of snow. Throughout the year, in Yakima, there are 18.5 snowfall days, and 7.8" (198mm) of snow is accumulated.Daylight
In Yakima, Washington, the average length of the day in September is 12h and 32min.On the first day of the month, sunrise is at 6:23 am and sunset at 7:40 pm. On the last day of September, sunrise is at 7:00 am and sunset at 6:42 pm PDT.
Sunshine
In September, the average sunshine is 11.1h.UV index
The average daily maximum UV index in September is 4. A UV Index estimate of 3 to 5 represents a moderate threat to health from unprotected exposure to Sun's UV rays for the ordinary person.Note: The daily high UV index of 4 during September translates into the following recommendations:
Guard yourself - Precautionary measures against sun damage are advocated. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. Employ a hat with a wide brim for robust protection, cutting UV exposure by half. Be advised! The UV radiation from the Sun can be almost doubled due to the reflective properties of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Yakima, WA
- Average high temperature in September: 74.8°F
The warmest month (with the highest average high temperature) is August (86.5°F).
The month with the lowest average high temperature is December (36.9°F).
- Average low temperature in September: 53.4°F
The month with the highest average low temperature is August (60.3°F).
The coldest month (with the lowest average low temperature) is December (25.5°F).
Average pressure in September
Yakima, 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
Yakima, WA
- Average wind speed in September: 6mph
The windiest month (with the highest average wind speed) is June (7.1mph).
The calmest month (with the lowest average wind speed) is December (4.4mph).
Average humidity in September
Yakima, WA
- Average humidity in September: 48%
The month with the highest relative humidity is January (81%).
The months with the lowest relative humidity are July and August (39%).
Average rainfall in September
Yakima, WA
- Average rainfall in September: 0.24"
The wettest month (with the highest rainfall) is January (0.87").
The driest month (with the least rainfall) is July (0.08").
Average rainfall days in September
Yakima, WA
- Average rainfall days in September: 3.9 days
The month with the highest number of rainy days is March (10.8 days).
The month with the least rainy days is August (2 days).
Average snowfall in September
Yakima, WA
- Average snowfall in September: 0.04"
The month with the highest snowfall is December (2.76").
The months with the least snowfall are April, May, June, July, August and October (0").
Average snowfall days in September
Yakima, WA
- Average snowfall days in September: 0.1 days
The month with the highest number of snowfall days is December (5.4 days).
The months with the least snowfall days are May, June, July, August and October (0 days).
Average daylight in September /
Average sunshine in September
Yakima, WA
- Average daylight in September: 12h and 30min
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: 11h and 6min
The months with the most sunshine are July and August (Average sunshine: 12h and 6min).
The month with the least sunshine is January (Average sunshine: 5h and 36min).
Average sunshine days in September
Yakima, WA
- Average sunshine days in September: 23.8 days
The month with the most sunshine days is July (27.5 days).
The month with the least sunshine days is February (15.8 days).
Average UV index in September
Yakima, 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
Yakima, WA
- Average cloud cover in September: 14
The month with the most cloud cover is January (Cloud cover 40).
The months with the least cloud cover are July and August (Cloud cover 9).
Average visibility in September
Yakima, WA
- Average visibility in September: 6mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).
