May weather forecast
Lake Oswego, OR

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Weather in May

May boasts inviting weather in Lake Oswego with an average temperature high climbing steeply to 66.7°F (19.3°C). This month marks the boundary between spring and summer with every passing day warming up progressively. The rain starts to ease off significantly, leaving a pleasant aroma of fresh soil and bloomed flowers. The daylight period increases noticeably, with an extension of almost an hour compared to April, signaling the longer, more relaxed days of summer. Whispers of summer winds begin to replace the refreshing breezes of spring, setting the stage for the upcoming season.

Temperature

The onset of May brings a minor temperature shift, with the average high-temperature moving from a moderate 58.6°F (14.8°C) in April to an enjoyable 66.7°F (19.3°C). Despite a significant deviation from daily highs, May sees an average nighttime temperature of 44.1°F (6.7°C).

Humidity

The average relative humidity in May is 72%.

Rainfall

In Lake Oswego, in May, it is raining for 13.9 days, with typically 1.77" (45mm) of accumulated precipitation. Throughout the year, there are 172.2 rainfall days, and 31.3" (795mm) of precipitation is accumulated.

Snowfall

April through October are months without snowfall.

Daylight

In Lake Oswego, the average length of the day in May is 14h and 55min.
On the first day of the month, sunrise is at 5:57 am and sunset at 8:17 pm. On the last day of May, sunrise is at 5:25 am and sunset at 8:51 pm PDT.

Sunshine

In May, the average sunshine is 8.8h.

UV index

The average daily maximum UV index in May in Lake Oswego, Oregon, is 4. A UV Index of 3 to 5 symbolizes a medium health hazard from unprotected exposure to Sun's UV rays for the ordinary person.
Note: In May, the average maximum UV index of 4 translates into the following recommendations:
Adopt protective measures - Requirement to safeguard skin and eyes from harm exists. The Sun is most powerful around mid-day, so it's a good practice to reduce direct exposure. Employ a hat with a wide brim for robust protection, cutting UV exposure by half.

Frequently asked questions

What is the temperature in May?

During May, Lake Oswego experiences an average high-temperature of 66.7°F (19.3°C) and a low-temperature of 44.1°F (6.7°C).

What is the average humidity in May?

In May, the average relative humidity is 72%.

How much does it rain in Lake Oswego in May?

In Lake Oswego, during May, the rain falls for 13.9 days and regularly aggregates up to 1.77" (45mm) of precipitation.

When it does not snow?

In Lake Oswego, snow does not fall in April through October.

What is the average length of the day in May?

The average day length in May is 14h and 55min.

What time are sunrise and sunset in May?

In May, on the first day of the month, sunrise is at 5:57 am and sunset at 8:17 pm. On the last day of the month, sunrise is at 5:25 am and sunset at 8:51 pm PDT.

How many hours of sunshine does Lake Oswego have in May?

In Lake Oswego, the average sunshine duration in May is 8.8h.

What is the UV index intensity in May?

In May, the average daily maximum UV index in Lake Oswego is 4. A UV Index value of 3 to 5 symbolizes a medium health risk from unsafe exposure to Sun's UV rays.
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
Lake Oswego, OR

Average temperature in May - Lake Oswego, OR
  • Average high temperature in May: 66.7°F

The warmest month (with the highest average high temperature) is August (81.7°F).
The month with the lowest average high temperature is December (44.4°F).

  • Average low temperature in May: 44.1°F

The month with the highest average low temperature is August (54.5°F).
The coldest month (with the lowest average low temperature) is December (34.7°F).

Average pressure in May
Lake Oswego, OR

Average pressure in May - Lake Oswego, OR
  • Average pressure in May: 30.03"Hg

The month with the highest atmospheric pressure is January (30.12"Hg).
The month with the lowest atmospheric pressure is August (30"Hg).

Average wind speed in May
Lake Oswego, OR

Average wind speed in May - Lake Oswego, OR
  • Average wind speed in May: 4.2mph

The windiest month (with the highest average wind speed) is January (6mph).
The calmest month (with the lowest average wind speed) is August (3.7mph).

Average humidity in May
Lake Oswego, OR

Average humidity in May - Lake Oswego, OR
  • Average humidity in May: 72%

The month with the highest relative humidity is February (84%).
The month with the lowest relative humidity is August (63%).

Average rainfall in May
Lake Oswego, OR

Average rainfall in May - Lake Oswego, OR
  • Average rainfall in May: 1.77"

The wettest month (with the highest rainfall) is December (4.57").
The driest month (with the least rainfall) is July (0.31").

Average rainfall days in May
Lake Oswego, OR

Average rainfall days in May - Lake Oswego, OR
  • Average rainfall days in May: 13.9 days

The month with the highest number of rainy days is March (20.4 days).
The month with the least rainy days is July (4.8 days).

Average snowfall in May
Lake Oswego, OR

Average snowfall in May - Lake Oswego, OR
  • Average snowfall in May: 0"

The month with the highest snowfall is March (1.46").
The months with the least snowfall are April, May, June, July, August, September and October (0").

Average snowfall days in May
Lake Oswego, OR

Average snowfall days in May - Lake Oswego, OR
  • Average snowfall days in May: 0 days

The month with the highest number of snowfall days is February (2.3 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

Average daylight in May /
Average sunshine in May
Lake Oswego, OR

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

The month with the longest days is June (Average daylight: 15h and 36min).
The month with the shortest days is December (Average daylight: 8h and 48min).

  • Average sunshine in May: 8h and 5min

The month with the most sunshine is August (Average sunshine: 11h and 0min).
The month with the least sunshine is February (Average sunshine: 4h and 12min).

Average sunshine days in May
Lake Oswego, OR

Average sunshine days in May - Lake Oswego, OR
  • Average sunshine days in May: 14.7 days

The month with the most sunshine days is July (23.9 days).
The month with the least sunshine days is February (8.3 days).

Average UV index in May
Lake Oswego, OR

Average UV index in May - Lake Oswego, OR
  • 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, November and December (UV index 2).

Average cloud cover in May
Lake Oswego, OR

Average cloud cover in May - Lake Oswego, OR
  • Average cloud cover in May: 46

The month with the most cloud cover is February (Cloud cover 57).
The month with the least cloud cover is August (Cloud cover 22).

Average visibility in May
Lake Oswego, OR

Average visibility in May - Lake Oswego, OR
  • Average visibility in May: 5mi

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

Lake Oswego, Oregon, USA

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