May weather forecast
Sisters, OR

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Weather in May

May brings about the first glimpses of summer and greets Sisters, Oregon with more far-reaching warmth. The high temperature break-outs register 60.1°F (15.6°C), rendering the air noticeably warmer than preceding months. The city witnesses less rainfall but benefits from increased sunlight hours. May is unmistakably associated with higher visibility, rewarded by reduced cloud cover. With calm winds and a high UV index, May is a significant deviation from the colder and gloomier start to the year.

Temperature

As May sets in Sisters, the average high-temperature shows an increase, moving up from a chilly 49.8°F (9.9°C) in April to a refreshing 60.1°F (15.6°C). Sisters experiences an average low-temperature of 39.2°F (4°C) in month of May.

Humidity

In Sisters, the average relative humidity in May is 66%.

Rainfall

In Sisters, in May, during 15 rainfall days, 2.01" (51mm) of precipitation is typically accumulated. Throughout the year, there are 142.1 rainfall days, and 22.87" (581mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through May, September through December. May is the last month it regularly snows. During 2.4 snowfall days, in May, Sisters aggregates 0.63" (16mm) of snow. Throughout the year, there are 70.7 snowfall days, and 60.04" (1525mm) of snow is accumulated.

Daylight

In May, the average length of the day is 14h and 49min.
On the first day of May, sunrise is at 5:55 am and sunset at 8:10 pm. On the last day of the month, sunrise is at 5:25 am and sunset at 8:42 pm PDT.

Sunshine

The average sunshine in May is 10.6h.

UV index

The average daily maximum UV index in May is 4. A UV Index reading of 3 to 5 represents a moderate health risk from unprotected exposure to Sun's UV rays for average individuals.
Note: The UV index of 4 in May translates into these instructions:
Preventative actions are necessary - Suggestions to safeguard against sun damage are in order. Solar radiation peaks around mid-day, so it's wise to limit exposure to the Sun at this time. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Be on the lookout! Nearly twofold UV radiation from the Sun can be reflected by snow.

Frequently asked questions

What are May temperatures?

In May, the average high-temperature and low-temperature are 60.1°F (15.6°C) and 39.2°F (4°C) respectively.

What is the average humidity in May?

In May, the average relative humidity is 66%.

How much does it rain in May?

In Sisters, during May, the rain falls for 15 days and regularly aggregates up to 2.01" (51mm) of precipitation.

What is the last month it snows?

May is the last month it regularly snows. During 2.4 snowfall days, in May, Sisters aggregates 0.63" (16mm) of snow.

What is the average length of the day in May in Sisters?

In Sisters, the average day length in May is 14h and 49min.

When are sunrise and sunset in May?

On the first day of May, sunrise is at 5:55 am and sunset at 8:10 pm. On the last day of the month, sunrise is at 5:25 am and sunset at 8:42 pm PDT.

How many hours of sunshine does Sisters have in May?

The average sunshine duration in May is 10.6h.

What is the UV index reading in May?

In May, the average daily maximum UV index is 4. A UV Index value of 3 to 5 symbolizes a medium health risk from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in May
Sisters, OR

Average temperature in May - Sisters, OR
  • Average high temperature in May: 60.1°F

The warmest month (with the highest average high temperature) is July (78.8°F).
The month with the lowest average high temperature is December (36.5°F).

  • Average low temperature in May: 39.2°F

The month with the highest average low temperature is August (50.7°F).
The coldest month (with the lowest average low temperature) is December (24.8°F).

Average pressure in May
Sisters, OR

Average pressure in May - Sisters, OR
  • Average pressure in May: 30"Hg

The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is August (29.98"Hg).

Average wind speed in May
Sisters, OR

Average wind speed in May - Sisters, OR
  • Average wind speed in May: 5.5mph

The windiest month (with the highest average wind speed) is February (6.1mph).
The calmest months (with the lowest average wind speed) are August and September (4.8mph).

Average humidity in May
Sisters, OR

Average humidity in May - Sisters, OR
  • Average humidity in May: 66%

The month with the highest relative humidity is December (84%).
The months with the lowest relative humidity are July and August (53%).

Average rainfall in May
Sisters, OR

Average rainfall in May - Sisters, OR
  • Average rainfall in May: 2.01"

The wettest month (with the highest rainfall) is January (3.31").
The driest month (with the least rainfall) is July (0.35").

Average rainfall days in May
Sisters, OR

Average rainfall days in May - Sisters, OR
  • Average rainfall days in May: 15 days

The month with the highest number of rainy days is March (16.9 days).
The month with the least rainy days is July (5 days).

Average snowfall in May
Sisters, OR

Average snowfall in May - Sisters, OR
  • Average snowfall in May: 0.63"

The month with the highest snowfall is February (13.74").
The months with the least snowfall are June, July and August (0").

Average snowfall days in May
Sisters, OR

Average snowfall days in May - Sisters, OR
  • Average snowfall days in May: 2.4 days

The month with the highest number of snowfall days is December (14.7 days).
The months with the least snowfall days are June, July and August (0 days).

Average daylight in May /
Average sunshine in May
Sisters, OR

Average daylight in May / Average sunshine in May - Sisters, OR
  • Average daylight in May: 14h and 5min

The month with the longest days is June (Average daylight: 15h and 30min).
The month with the shortest days is December (Average daylight: 8h and 54min).

  • Average sunshine in May: 10h and 4min

The month with the most sunshine is July (Average sunshine: 12h and 0min).
The month with the least sunshine is December (Average sunshine: 5h and 6min).

Average sunshine days in May
Sisters, OR

Average sunshine days in May - Sisters, OR
  • Average sunshine days in May: 11.9 days

The month with the most sunshine days is July (23.3 days).
The month with the least sunshine days is March (8.1 days).

Average UV index in May
Sisters, OR

Average UV index in May - Sisters, OR
  • Average UV index in May: 4

The month with the highest UV index is July (UV index 6).
The month with the lowest UV index is February (UV index 1).

Average cloud cover in May
Sisters, OR

Average cloud cover in May - Sisters, OR
  • Average cloud cover in May: 33

The months with the most cloud cover are January, February, March and December (Cloud cover 49).
The month with the least cloud cover is July (Cloud cover 11).

Average visibility in May
Sisters, OR

Average visibility in May - Sisters, OR
  • Average visibility in May: 6mi

The months with the highest visibility are April, May, June, July, August, September, October and November (6mi).
The months with the lowest visibility are January, February, March and December (5mi).

Sisters, Oregon, USA

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