May weather forecastCoulee Dam, WA
May
Weather in May
The last month of the spring, May, is a comfortable month in Coulee Dam, Washington, with an average temperature varying between 67.6°F (19.8°C) and 46°F (7.8°C).Temperature
May's arrival signals an increase in average high-temperatures, moving from April's moderate 57°F (13.9°C) to a comfortable 67.6°F (19.8°C). Coulee Dam reports a substantial plunge from daytime highs during the nights of May, with an average low-temperature of 46°F (7.8°C).Humidity
In Coulee Dam, the average relative humidity in May is 52%.Rainfall
The wettest months are May and December, with an average 1.18" (30mm) of rainfall.Snowfall
In Coulee Dam, snow does not fall in May through August.Daylight
In Coulee Dam, Washington, the average length of the day in May is 15h and 12min.On the first day of May, sunrise is at 5:36 am and sunset at 8:09 pm. On the last day of the month, sunrise is at 5:00 am and sunset at 8:46 pm PDT.
Sunshine
In Coulee Dam, the average sunshine in May is 10.9h.UV index
In Coulee Dam, the average daily maximum UV index in May is 5. A UV Index reading of 3 to 5 represents a medium health hazard from exposure to the Sun's UV rays for the average person.Note: In May, the maximum UV index of 5 transforms into these recommendations:
Ensure safety - Sun damage prevention is strongly urged. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. Loose clothes with a tight weave are optimal for safeguarding yourself against the Sun's rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in May
Coulee Dam, WA
- Average high temperature in May: 67.6°F
The warmest month (with the highest average high temperature) is July (84.9°F).
The month with the lowest average high temperature is December (31.6°F).
- Average low temperature in May: 46°F
The month with the highest average low temperature is August (61.3°F).
The coldest month (with the lowest average low temperature) is December (21.4°F).
Average pressure in May
Coulee Dam, WA
- Average pressure in May: 29.94"Hg
The month with the highest atmospheric pressure is January (30.18"Hg).
The month with the lowest atmospheric pressure is August (29.91"Hg).
Average wind speed in May
Coulee Dam, WA
- Average wind speed in May: 6.3mph
The windiest month (with the highest average wind speed) is April (7mph).
The calmest month (with the lowest average wind speed) is January (4.9mph).
Average humidity in May
Coulee Dam, WA
- Average humidity in May: 52%
The month with the highest relative humidity is January (89%).
The month with the lowest relative humidity is August (36%).
Average rainfall in May
Coulee Dam, WA
- Average rainfall in May: 1.18"
The wettest months (with the highest rainfall) are May and December (1.18").
The driest months (with the least rainfall) are July and August (0.2").
Average rainfall days in May
Coulee Dam, WA
- Average rainfall days in May: 10.8 days
The month with the highest number of rainy days is March (12.1 days).
The month with the least rainy days is August (3.2 days).
Average snowfall in May
Coulee Dam, WA
- Average snowfall in May: 0"
The month with the highest snowfall is January (4.41").
The months with the least snowfall are May, June, July and August (0").
Average snowfall days in May
Coulee Dam, WA
- Average snowfall days in May: 0 days
The month with the highest number of snowfall days is December (10.5 days).
The months with the least snowfall days are May, June, July and August (0 days).
Average daylight in May /
Average sunshine in May
Coulee Dam, WA
- Average daylight in May: 15h and 12min
The month with the longest days is June (Average daylight: 16h and 0min).
The month with the shortest days is December (Average daylight: 8h and 30min).
- Average sunshine in May: 10h and 54min
The month with the most sunshine is August (Average sunshine: 12h and 6min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).
Average sunshine days in May
Coulee Dam, WA
- Average sunshine days in May: 18 days
The month with the most sunshine days is August (25.8 days).
The month with the least sunshine days is March (14.7 days).
Average UV index in May
Coulee Dam, WA
- Average UV index in May: 5
The month with the highest UV index is July (UV index 7).
The month with the lowest UV index is November (UV index 1).
Average cloud cover in May
Coulee Dam, WA
- Average cloud cover in May: 28
The month with the most cloud cover is January (Cloud cover 55).
The months with the least cloud cover are July and August (Cloud cover 12).
Average visibility in May
Coulee Dam, WA
- Average visibility in May: 6mi
The months with the highest visibility are March, April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January and December (4mi).
