May weather forecast
Sammamish, WA

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Dense pine tree cover and houses in the town of Sammamish, Washington, in the Pine Lake area
Dense pine tree cover and houses in the town of Sammamish, Washington, in the Pine Lake area

Weather in May

May offers a marked departure from the cooler temperatures of spring to the incoming warmth of summer. As Sammamish transitions into a warmer season, the city experiences a maximum temperature of 64.4°F (18°C). This change in climate is also seen in the declining rainfall, which is at its second lowest in the year. May also brings longer daylight hours and more sunshine, enhancing the city's vibrant atmosphere. Meanwhile, the consistent wind speeds provide a gentle breeze, which is a welcome relief from the increasing warmth.

Temperature

Sammamish experiences a minor temperature shift with the start of May, with average high-temperatures moving from a moderate 55.8°F (13.2°C) in April to a still refreshing 64.4°F (18°C). Throughout May, Sammamish braces for a considerable drop from daytime highs, with an average low-temperature of 42.6°F (5.9°C).

Humidity

In May, the average relative humidity is 75%.

Rainfall

In Sammamish, during May, the rain falls for 10.5 days and regularly aggregates up to 0.79" (20mm) of precipitation. In Sammamish, during the entire year, the rain falls for 136.7 days and collects up to 13.39" (340mm) of precipitation.

Snowfall

In Sammamish, snow does not fall in May through October.

Daylight

In Sammamish, Washington, the average length of the day in May is 15h and 10min.
On the first day of May, sunrise is at 5:49 am and sunset at 8:20 pm. On the last day of the month, sunrise is at 5:14 am and sunset at 8:57 pm PDT.

Sunshine

In Sammamish, the average sunshine in May is 9h.

UV index

The average daily maximum UV index in May is 4. A UV Index reading of 3 to 5 represents a moderate threat to health from exposure to the Sun's UV rays for average individuals.
Note: The daily high UV index of 4 during May translates into the following recommendations:
Preventative actions are necessary - The mandate to avoid skin and eye damage is in place. To protect against the Sun's most potent rays, avoid direct exposure around midday. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays.
Updated: Aug 31, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What is the average May temperature?

During May, Sammamish experiences an average high-temperature of 64.4°F (18°C) and a low-temperature of 42.6°F (5.9°C).

What is the average humidity in May?

The average relative humidity in May is 75%.

How much does it rain in Sammamish in May?

In Sammamish, during May, the rain falls for 10.5 days and regularly aggregates up to 0.79" (20mm) of precipitation.

When it does not snow?

In Sammamish, snow does not fall in May through October.

Does it snow in Sammamish in May?

In May, it doesn't snow. April is the latest month when it typically snows.

What is the average length of the day in May?

In Sammamish, the average day length in May is 15h and 10min.

When is the sunrise / sunset in May?

In May, on the first day of the month, sunrise is at 5:49 am and sunset at 8:20 pm. On the last day of the month, sunrise is at 5:14 am and sunset at 8:57 pm PDT.

How many hours of sunshine does Sammamish have in May?

In May, the average sunshine duration is 9h.

How high is the UV index in May?

The average daily maximum UV index in May is 4. A UV Index of 3 to 5 symbolizes a medium hazard to health from unprotected exposure to UV radiation.
Average humidity
Average rainfall days
Average snowfall
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in May
Sammamish, WA

Average temperature in May - Sammamish, WA
  • Average high temperature in May: 64.4°F

The warmest month (with the highest average high temperature) is August (76.5°F).
The month with the lowest average high temperature is December (42.3°F).

  • Average low temperature in May: 42.6°F

The month with the highest average low temperature is August (52.2°F).
The coldest month (with the lowest average low temperature) is December (33.6°F).

Average pressure in May
Sammamish, WA

Average pressure in May - Sammamish, WA
  • Average pressure in May: 30.02"Hg

The month with the highest atmospheric pressure is January (30.1"Hg).
The month with the lowest atmospheric pressure is August (30"Hg).

Average wind speed in May
Sammamish, WA

Average wind speed in May - Sammamish, WA
  • Average wind speed in May: 3.8mph

The windiest month (with the highest average wind speed) is January (5mph).
The calmest month (with the lowest average wind speed) is August (3.4mph).

Average humidity in May
Sammamish, WA

Average humidity in May - Sammamish, WA
  • Average humidity in May: 75%

The months with the highest relative humidity are January, February and December (85%).
The month with the lowest relative humidity is July (70%).

Average rainfall in May
Sammamish, WA

Average rainfall in May - Sammamish, WA
  • Average rainfall in May: 0.79"

The wettest month (with the highest rainfall) is December (1.85").
The driest months (with the least rainfall) are July and August (0.35").

Average rainfall days in May
Sammamish, WA

Average rainfall days in May - Sammamish, WA
  • Average rainfall days in May: 10.5 days

The month with the highest number of rainy days is March (14.8 days).
The month with the least rainy days is August (5.2 days).

Average snowfall in May
Sammamish, WA

Average snowfall in May - Sammamish, WA
  • Average snowfall in May: 0"

The month with the highest snowfall is February (1.38").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in May
Sammamish, WA

Average snowfall days in May - Sammamish, WA
  • Average snowfall days in May: 0 days

The month with the highest number of snowfall days is February (3.2 days).
The months with the least snowfall days are May, June, July, August and October (0 days).

Average daylight in May /
Average sunshine in May
Sammamish, WA

Average daylight in May / Average sunshine in May - Sammamish, WA
  • Average daylight in May: 15h and 1min

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

  • Average sunshine in May: 9h and 0min

The month with the most sunshine is August (Average sunshine: 10h and 42min).
The months with the least sunshine are January and December (Average sunshine: 4h and 12min).

Average sunshine days in May
Sammamish, WA

Average sunshine days in May - Sammamish, WA
  • Average sunshine days in May: 17.7 days

The month with the most sunshine days is August (24 days).
The month with the least sunshine days is November (13.5 days).

Average UV index in May
Sammamish, WA

Average UV index in May - Sammamish, WA
  • Average UV index in May: 4

The months with the highest UV index are June and July (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 2).

Average cloud cover in May
Sammamish, WA

Average cloud cover in May - Sammamish, WA
  • Average cloud cover in May: 44

The month with the most cloud cover is December (Cloud cover 57).
The month with the least cloud cover is August (Cloud cover 26).

Average visibility in May
Sammamish, WA

Average visibility in May - Sammamish, WA
  • Average visibility in May: 5mi

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

Sammamish, Washington, USA

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