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
May comes with an increase, with the average high-temperature moving from a cool 52.2°F (11.2°C) in April to a comfortable 62.4°F (16.9°C). Throughout the nights in May, Riley experiences an average low-temperature of 42.1°F (5.6°C).Humidity
The average relative humidity in May is 52%.Rainfall
In Riley, in May, it is raining for 11.9 days, with typically 1.02" (26mm) of accumulated precipitation. Throughout the year, there are 125.1 rainfall days, and 11.26" (286mm) of precipitation is accumulated.Snowfall
April through October are months without snowfall.Daylight
In May, the average length of the day is 14h and 44min.On the first day of May, sunrise is at 5:49 am and sunset at 8:00 pm. On the last day of the month, sunrise is at 5:19 am and sunset at 8:31 pm PDT.
Sunshine
In Riley, the average sunshine in May is 11h.UV index
In May, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a moderate threat to health from exposure to the Sun's UV rays for average individuals.Note: A maximum daily UV index of 4 during May morphs into the following directions:
Proceed with care. Light skin individuals may be exposed to burns in fewer than 30 minutes. The intensity of the Sun's UV radiation during midday suggests reducing time spent outdoors. In the presence of strong sunlight, it's crucial to wear sunglasses that ward off UVA and UVB rays.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are May temperatures?
What is the average humidity in May?
How much does it rain in May?
When it does not snow?
What is the average length of the day in May?
When are sunrise and sunset in May?
How many hours of sunshine does Riley have in May?
What is the UV index intensity in May?
Average temperature in May
Riley, OR
- Average high temperature in May: 62.4°F
The warmest month (with the highest average high temperature) is July (82.9°F).
The month with the lowest average high temperature is December (33.1°F).
- Average low temperature in May: 42.1°F
The month with the highest average low temperature is August (58.1°F).
The coldest month (with the lowest average low temperature) is December (21.2°F).
Average pressure in May
Riley, OR
- Average pressure in May: 29.96"Hg
The month with the highest atmospheric pressure is January (30.22"Hg).
The month with the lowest atmospheric pressure is August (29.94"Hg).
Average wind speed in May
Riley, OR
- Average wind speed in May: 9.3mph
The windiest month (with the highest average wind speed) is April (9.9mph).
The calmest month (with the lowest average wind speed) is August (7.5mph).
Average humidity in May
Riley, OR
- Average humidity in May: 52%
The month with the highest relative humidity is December (83%).
The months with the lowest relative humidity are July and August (33%).
Average rainfall in May
Riley, OR
- Average rainfall in May: 1.02"
The wettest month (with the highest rainfall) is December (1.54").
The driest month (with the least rainfall) is July (0.16").
Average rainfall days in May
Riley, OR
- Average rainfall days in May: 11.9 days
The month with the highest number of rainy days is March (17.7 days).
The month with the least rainy days is August (3.3 days).
Average snowfall in May
Riley, OR
- Average snowfall in May: 0"
The month with the highest snowfall is December (0.87").
The months with the least snowfall are April, May, June, July, August, September and October (0").
Average snowfall days in May
Riley, OR
- Average snowfall days in May: 0 days
The month with the highest number of snowfall days is December (3.1 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average daylight in May /
Average sunshine in May
Riley, OR
- Average daylight in May: 14h and 4min
The month with the longest days is June (Average daylight: 15h and 24min).
The month with the shortest days is December (Average daylight: 9h and 0min).
- Average sunshine in May: 11h and 0min
The month with the most sunshine is July (Average sunshine: 12h and 6min).
The month with the least sunshine is December (Average sunshine: 5h and 12min).
Average sunshine days in May
Riley, OR
- Average sunshine days in May: 16.5 days
The months with the most sunshine days are July and August (25.3 days).
The month with the least sunshine days is March (11.5 days).
Average UV index in May
Riley, OR
- Average UV index in May: 4
The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are January, February, March, November and December (UV index 2).
Average cloud cover in May
Riley, OR
- Average cloud cover in May: 28
The month with the most cloud cover is December (Cloud cover 47).
The months with the least cloud cover are July and August (Cloud cover 9).
Average visibility in May
Riley, OR
- Average visibility in May: 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).
Riley, Oregon, USA
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