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's arrival in Keystone signals a temperature shift, moving from a fresh 50.9°F (10.5°C) in April to an enjoyable 61°F (16.1°C). Throughout May, an average low-temperature of 42.4°F (5.8°C) is expected in Keystone.Humidity
In May, the average relative humidity is 66%.Rainfall
In May, the rain falls for 18.6 days. Throughout May, 3.11" (79mm) of precipitation is accumulated. Throughout the year, in Keystone, there are 135.4 rainfall days, and 20.39" (518mm) of precipitation is accumulated.Snowfall
January through May, September through December are months with snowfall. May is the last month it regularly snows in Keystone, South Dakota. During 3.4 snowfall days, in May, Keystone aggregates 4.09" (104mm) of snow. Throughout the year, in Keystone, there are 75.1 snowfall days, and 40.24" (1022mm) of snow is accumulated.Daylight
In Keystone, South Dakota, the average length of the day in May is 14h and 46min.On the first day of May, sunrise is at 5:44 am and sunset at 7:57 pm. On the last day of the month, sunrise is at 5:14 am and sunset at 8:28 pm MDT.
Sunshine
The average sunshine in May in Keystone is 10.1h.UV index
In May, the average daily maximum UV index in Keystone, South Dakota, is 4. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV radiation for the average person.Note: A maximum daily UV index of 4 during May morphs into the following directions:
Adopt protective measures - Suggestions to resist sunburn are offered. When the Sun is at its strongest around midday, find shade and limit exposure. For holistic sun protection encompassing the eyes, ears, face, and neck, a wide-brim hat is key. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
Frequently asked questions
What is the usual temperature for Keystone in May?
What is the average humidity in May in Keystone?
How much does it rain in Keystone in May?
What is the last month it snows in Keystone?
What is the average length of the day in May in Keystone?
When are sunrise and sunset in May in Keystone?
How many hours of sunshine does Keystone have in May?
What is the UV index reading in May in Keystone?
Average temperature in May
Keystone, SD
- Average high temperature in May: 61°F
The warmest month (with the highest average high temperature) is July (81.7°F).
The month with the lowest average high temperature is December (29.8°F).
- Average low temperature in May: 42.4°F
The month with the highest average low temperature is July (60.4°F).
The coldest month (with the lowest average low temperature) is February (16.2°F).
Average pressure in May
Keystone, SD
- Average pressure in May: 29.91"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.84"Hg).
Average wind speed in May
Keystone, SD
- Average wind speed in May: 8.9mph
The windiest month (with the highest average wind speed) is April (9.5mph).
The calmest month (with the lowest average wind speed) is August (7mph).
Average humidity in May
Keystone, SD
- Average humidity in May: 66%
The months with the highest relative humidity are January and February (77%).
The months with the lowest relative humidity are August and September (52%).
Average rainfall in May
Keystone, SD
- Average rainfall in May: 3.11"
The wettest month (with the highest rainfall) is June (3.19").
The driest month (with the least rainfall) is January (0.47").
Average rainfall days in May
Keystone, SD
- Average rainfall days in May: 18.6 days
The month with the highest number of rainy days is May (18.6 days).
The month with the least rainy days is November (4.5 days).
Average snowfall in May
Keystone, SD
- Average snowfall in May: 4.09"
The month with the highest snowfall is April (7.24").
The months with the least snowfall are June, July and August (0").
Average snowfall days in May
Keystone, SD
- Average snowfall days in May: 3.4 days
The month with the highest number of snowfall days is February (12.9 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight in May /
Average sunshine in May
Keystone, SD
- Average daylight in May: 14h and 5min
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: 10h and 1min
The month with the most sunshine is August (Average sunshine: 11h and 42min).
The month with the least sunshine is February (Average sunshine: 6h and 0min).
Average sunshine days in May
Keystone, SD
- Average sunshine days in May: 7.8 days
The month with the most sunshine days is November (19.2 days).
The month with the least sunshine days is May (7.8 days).
Average UV index in May
Keystone, SD
- Average UV index in May: 4
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, February, March, October, November and December (UV index 2).
Average cloud cover in May
Keystone, SD
- Average cloud cover in May: 35
The month with the most cloud cover is April (Cloud cover 38).
The month with the least cloud cover is August (Cloud cover 17).
Average visibility in May
Keystone, SD
- Average visibility in May: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Keystone, South Dakota, USA
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