September weather forecastLacey, WA
September
Weather in September
September witnesses the beginning of the gradual transition from summer to autumn. Temperatures start to decline, and the days become shorter. The rainfall also sees a significant increase from 0.47" (12mm) to 1.81" (46mm), hinting at the arrival of the wet season. However, September still enjoys an average of 8.3h of sunshine, wrapping summer with a vibrant mix of warm and cool days.Temperature
Lacey's transition into September involves a gentle shift in temperature, receding from a warm 78.6°F (25.9°C) in August to a pleasant 70.5°F (21.4°C). September nights are characterized by a significant departure from the daytime highs, dropping to an average temperature of 47.7°F (8.7°C).Humidity
In Lacey, the average relative humidity in September is 78%.Rainfall
In Lacey, Washington, during September, the rain falls for 11.7 days and regularly aggregates up to 1.81" (46mm) of precipitation. In Lacey, during the entire year, the rain falls for 177.4 days and collects up to 37.05" (941mm) of precipitation.Snowfall
April through October are months without snowfall.Daylight
The average length of the day in September is 12h and 32min.On the first day of the month, sunrise is at 6:31 am and sunset at 7:50 pm. On the last day of September, sunrise is at 7:09 am and sunset at 6:52 pm PDT.
Sunshine
The average sunshine in September is 8.3h.UV index
In September, the average daily maximum UV index is 4. A UV Index of 3 to 5 symbolizes 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. Midday is the peak time for the Sun's radiation; stay in the shade and protect yourself. For optimum UV protection, wear sun-resistant attire complemented with a hat and quality shades.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in September
Lacey, WA
- Average high temperature in September: 70.5°F
The warmest month (with the highest average high temperature) is August (78.6°F).
The month with the lowest average high temperature is December (43°F).
- Average low temperature in September: 47.7°F
The month with the highest average low temperature is August (50.5°F).
The coldest month (with the lowest average low temperature) is December (33.4°F).
Average pressure in September
Lacey, WA
- Average pressure in September: 30.02"Hg
The month with the highest atmospheric pressure is January (30.09"Hg).
The month with the lowest atmospheric pressure is March (30.01"Hg).
Average wind speed in September
Lacey, WA
- Average wind speed in September: 3.8mph
The windiest months (with the highest average wind speed) are March and November (4.6mph).
The calmest month (with the lowest average wind speed) is September (3.8mph).
Average humidity in September
Lacey, WA
- Average humidity in September: 78%
The months with the highest relative humidity are January, November and December (89%).
The month with the lowest relative humidity is July (71%).
Average rainfall in September
Lacey, WA
- Average rainfall in September: 1.81"
The wettest month (with the highest rainfall) is December (5.79").
The driest month (with the least rainfall) is July (0.39").
Average rainfall days in September
Lacey, WA
- Average rainfall days in September: 11.7 days
The month with the highest number of rainy days is March (20.4 days).
The month with the least rainy days is August (5.5 days).
Average snowfall in September
Lacey, WA
- Average snowfall in September: 0"
The month with the highest snowfall is February (2.32").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in September
Lacey, WA
- Average snowfall days in September: 0 days
The month with the highest number of snowfall days is February (3.3 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in September /
Average sunshine in September
Lacey, 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: 8h and 18min
The month with the most sunshine is August (Average sunshine: 10h and 12min).
The month with the least sunshine is December (Average sunshine: 3h and 24min).
Average sunshine days in September
Lacey, WA
- Average sunshine days in September: 16.1 days
The month with the most sunshine days is August (22.4 days).
The month with the least sunshine days is February (8.4 days).
Average UV index in September
Lacey, WA
- Average UV index in September: 4
The months with the highest UV index are June and July (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in September
Lacey, WA
- Average cloud cover in September: 45
The months with the most cloud cover are January and December (Cloud cover 65).
The months with the least cloud cover are July and August (Cloud cover 35).
Average visibility in September
Lacey, WA
- Average visibility in September: 4mi
The months with the highest visibility are June, July and August (5mi).
The months with the lowest visibility are January, February, March, April, May, September, October, November and December (4mi).
