May weather forecast
Unalaska, AK

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Weather in May

In May, Unalaska feels a stronger flow of spring warmth with the average high temperature rising to over 40°F (4.4°C). The snowfall disappears completely, replaced by precipitation at other times. The increased daylight hours and sunshine duration add to a more comfortable and pleasant environment. Elevated relative humidity levels indicate a moist atmosphere during May. Even with longer sunlight duration, UV exposure levels remain moderate and pose minimal risk.

Temperature

Unalaska's weather, upon May's arrival, documents an average high-temperature of a still cold 41.4°F (5.2°C), nearly identical to the prior month. Unalaska's nighttime temperature in May consistently rests at a still wintry 37.9°F (3.3°C).

Humidity

In Unalaska, the average relative humidity in May is 87%.

Rainfall

In May, in Unalaska, the rain falls for 18.8 days. Throughout May, 2.36" (60mm) of precipitation is accumulated. Throughout the year, there are 198.8 rainfall days, and 33.78" (858mm) of precipitation is accumulated.

Snowfall

Months with snowfall are January through May, October through December. May is the last month it regularly snows in Unalaska. During 4.1 snowfall days, in May, Unalaska aggregates 1.18" (30mm) of snow. Throughout the year, there are 78.3 snowfall days, and 30.39" (772mm) of snow is accumulated.

Ocean temperature

In Unalaska, Alaska, in May, the average water temperature is 41.4°F (5.2°C).
Note: At temperatures below 50°F (10°C), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 55.4°F (13°C) is not comfortable.

Daylight

In May, the average length of the day in Unalaska, Alaska, is 16h and 1min.
On the first day of May, sunrise is at 7:27 am and sunset at 10:38 pm. On the last day of the month, sunrise is at 6:41 am and sunset at 11:26 pm AKDT.

Sunshine

In Unalaska, the average sunshine in May is 5.2h.

UV index

In Unalaska, the average daily maximum UV index in May is 2. A UV Index estimate of 2, and below, represents a low threat to health from exposure to the Sun's UV radiation for the ordinary person.
Note: A daily high UV index of 2 in May leads to these guidelines:
While most can endure approximately an hour in the sun without burning, children always require protection from sunlight. Avoiding direct sunlight during midday hours helps reduce the risk from intense UV radiation. Boost your sun resistance with garments that are densely woven yet spacious. Mark this! Snow reflection can nearly double the UV radiation intensity from the Sun.
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Frequently asked questions

How cold does it get in Unalaska in May?

The high-temperature, in May, in Unalaska, is 41.4°F (5.2°C), while the low-temperature averages to 37.9°F (3.3°C).

What is the average humidity in May in Unalaska?

In Unalaska, Alaska, the average relative humidity in May is 87%.

How many days does it rain in May in Unalaska?

In Unalaska, in May, during 18.8 rainfall days, 2.36" (60mm) of precipitation is typically accumulated.

What is the last month it snows in Unalaska?

May is the last month it regularly snows in Unalaska, Alaska. During 4.1 snowfall days, in May, Unalaska aggregates 1.18" (30mm) of snow.

What is the water temperature in May in Unalaska?

In May, the average ocean temperature is 41.4°F (5.2°C). At temperatures below 50°F (10°C), swimming in a suitably protected swimsuit is feasible; otherwise, cold shock and loss of breathing control are imminent. Even a short swim, without thermal protection, at temperatures around 55.4°F (13°C) is not comfortable.

How many hours of daylight does Unalaska have in May?

In Unalaska, the average day length in May is 16h and 1min.

When is the sunrise / sunset in May in Unalaska?

In May, on the first day of the month, sunrise is at 7:27 am and sunset at 10:38 pm. On the last day of the month, in Unalaska, Alaska, sunrise is at 6:41 am and sunset at 11:26 pm AKDT.

How long on average sun shines in May in Unalaska?

In May, the average sunshine duration in Unalaska, Alaska, is 5.2h.

What is the UV index reading in May in Unalaska?

In May, the average daily maximum UV index in Unalaska is 2. A UV Index estimate of 2, and below, represents a low health threat from unprotected exposure to UV radiation.
Today
Tomorrow
Long-term
YearJFMAMayJJASOND
Apr
May
Jun
Average high temperature
37.4°F 3°C
41.4°F 5.2°C
46.4°F 8°C
Average low temperature
33.4°F 0.8°C
37.9°F 3.3°C
43°F 6.1°C
Average pressure
29.72" 755mmHg
29.84" 758mmHg
29.88" 759mmHg
Average wind speed
14.4mph 23.2km/h
10.8mph 17.4km/h
9.6mph 15.4km/h
Average max. wind speed
15.1mph 24.3km/h
11.4mph 18.3km/h
10.1mph 16.3km/h
Average wind speed gusts
20.6mph 33.2km/h
16.3mph 26.2km/h
15.3mph 24.6km/h
Average humidity
84%
87%
89%
Average rainfall
2.44" 62mm
2.36" 60mm
2.13" 54mm
Average rainfall days
15.8
18.8
17.2
Average snowfall
4.09" 104mm
1.18" 30mm
0" 0mm
Average snowfall days
12.2
4.1
0
Average sea temperature
39°F 3.9°C
41.4°F 5.2°C
44.5°F 6.9°C
Average daylight
14h 1min
16h 0min
17h 0min
Average sunshine
4h 2min
5h 1min
5h 5min
Average sunshine days
3.8
7.8
8.8
Average UV index
1
2
2
Average cloud cover
73%
70%
70%
Average visibility
5mi 8km
6mi 9.7km
6mi 9.7km

Average temperature in May
Unalaska, AK

Average temperature in May - Unalaska, AK
  • Average high temperature in May: 41.4°F

The warmest month (with the highest average high temperature) is August (53.2°F).
The month with the lowest average high temperature is March (34.7°F).

  • Average low temperature in May: 37.9°F

The month with the highest average low temperature is August (49.6°F).
The coldest month (with the lowest average low temperature) is March (30.7°F).

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Average pressure in May
Unalaska, AK

Average pressure in May - Unalaska, AK
  • Average pressure in May: 29.84"Hg

The month with the highest atmospheric pressure is July (29.98"Hg).
The month with the lowest atmospheric pressure is January (29.5"Hg).

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Average wind speed in May
Unalaska, AK

Average wind speed in May - Unalaska, AK
  • Average wind speed in May: 10.8mph

The windiest months (with the highest average wind speed) are November and December (16.5mph).
The calmest month (with the lowest average wind speed) is July (9.1mph).

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Average humidity in May
Unalaska, AK

Average humidity in May - Unalaska, AK
  • Average humidity in May: 87%

The month with the highest relative humidity is July (91%).
The months with the lowest relative humidity are November and December (80%).

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Average rainfall in May
Unalaska, AK

Average rainfall in May - Unalaska, AK
  • Average rainfall in May: 2.36"

The wettest month (with the highest rainfall) is December (4.21").
The driest month (with the least rainfall) is July (1.85").

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Average rainfall days in May
Unalaska, AK

Average rainfall days in May - Unalaska, AK
  • Average rainfall days in May: 18.8 days

The month with the highest number of rainy days is October (21.8 days).
The month with the least rainy days is February (11.1 days).

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Average snowfall in May
Unalaska, AK

Average snowfall in May - Unalaska, AK
  • Average snowfall in May: 1.18"

The month with the highest snowfall is January (6.97").
The months with the least snowfall are June, July, August and September (0").

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Average snowfall days in May
Unalaska, AK

Average snowfall days in May - Unalaska, AK
  • Average snowfall days in May: 4.1 days

The month with the highest number of snowfall days is January (14.2 days).
The months with the least snowfall days are June, July, August and September (0 days).

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Average sea temperature in May
Unalaska, AK

Average sea temperature in May - Unalaska, AK
  • Average sea temperature in May: 41.4°F

The best month for swimming (with the highest average sea temperature) is August (50.1°F).
The coldest month (with the lowest average sea temperature) is February (38.8°F).

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Average daylight in May /
Average sunshine in May
Unalaska, AK

Average daylight in May / Average sunshine in May - Unalaska, AK
  • Average daylight in May: 16h and 0min

The month with the longest days is June (Average daylight: 17h and 0min).
The month with the shortest days is December (Average daylight: 7h and 30min).

  • Average sunshine in May: 5h and 1min

The month with the most sunshine is June (Average sunshine: 5h and 48min).
The month with the least sunshine is December (Average sunshine: 2h and 0min).

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Average sunshine days in May
Unalaska, AK

Average sunshine days in May - Unalaska, AK
  • Average sunshine days in May: 7.8 days

The month with the most sunshine days is August (9.7 days).
The month with the least sunshine days is April (3.8 days).

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Average UV index in May
Unalaska, AK

Average UV index in May - Unalaska, AK
  • Average UV index in May: 2

The months with the highest UV index are July and August (UV index 3).
The months with the lowest UV index are February, March, April and November (UV index 1).

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Average cloud cover in May
Unalaska, AK

Average cloud cover in May - Unalaska, AK
  • Average cloud cover in May: 70

The month with the most cloud cover is July (Cloud cover 74).
The months with the least cloud cover are September and October (Cloud cover 66).

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Average visibility in May
Unalaska, AK

Average visibility in May - Unalaska, AK
  • Average visibility in May: 6mi

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

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Unalaska, Alaska, USA

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