Contents
- Weather in May
- Frequently asked questions
- Average temperature in May
- Average pressure in May
- Average wind speed in May
- Average humidity in May
- Average rainfall in May
- Average rainfall days in May
- Average snowfall in May
- Average snowfall days in May
- Average daylight in May
- Average sunshine in May
- Average sunshine days in May
- Average UV index in May
- Average cloud cover in May
- Average visibility in May
Weather in May
Temperature
Grand Coulee experiences a temperature shift with the start of May, with average high-temperatures moving from a mild 57°F (13.9°C) in April to a comfortable 67.6°F (19.8°C). Grand Coulee undergoes a major shift from daytime highs, averaging a chilly 46°F (7.8°C) during the night in May.Humidity
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
May through August are months without snowfall.Daylight
In May, the average length of the day is 15h and 12min.On the first day of the month, sunrise is at 5:36 am and sunset at 8:09 pm. On the last day of May, in Grand Coulee, sunrise is at 5:00 am and sunset at 8:46 pm PDT.
Sunshine
The average sunshine in May in Grand Coulee, Washington, is 10.9h.UV index
In May, the average daily maximum UV index in Grand Coulee is 5. A UV Index of 3 to 5 symbolizes a moderate threat to health from unprotected exposure to Sun's UV rays for the average person.Note: A maximum high UV index of 5 in May translates into the following recommendations:
Make use of precautions - Shielding skin and eyes from injury is a requirement. Sun's radiation is most powerful around mid-day, so it's best to limit outdoor activities during this time. For excellent sun protection for the eyes, ears, face, and neck, consider a wide-brim hat.
Frequently asked questions
What are the temperatures in Grand Coulee in May?
What is the average humidity in May in Grand Coulee?
What is the rainiest month in Grand Coulee?
How many days does it rain in May in Grand Coulee?
When it does not snow in Grand Coulee?
Does it snow in Grand Coulee in May?
What is the average length of the day in May in Grand Coulee?
When are sunrise and sunset in May in Grand Coulee?
How many hours of sunshine does Grand Coulee have in May?
What is the UV index reading in May in Grand Coulee?
Average temperature in May
Grand Coulee, 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
Grand Coulee, 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
Grand Coulee, 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
Grand Coulee, 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
Grand Coulee, 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
Grand Coulee, 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
Grand Coulee, 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
Grand Coulee, 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
Grand Coulee, WA
- Average daylight in May: 15h and 1min
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 5min
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
Grand Coulee, 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
Grand Coulee, 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
Grand Coulee, 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
Grand Coulee, 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).
Grand Coulee, Washington, USA
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