Frost Dates for Unalaska, AK

Based on data from Dutch Harbor weather station, 1 miles away

Frost Dates

Last Spring Frost (50%) iA 50% chance that the last spring frost has already passed by this date. Most gardeners use this as their primary planting guide. May 6
First Fall Frost (50%) iA 50% chance that the first fall frost has occurred by this date. Plan to harvest or protect tender plants before this date. October 18
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

30% Probability iOnly a 30% chance of frost remaining by this date. Use these dates for a safer planting window, especially for tender plants sensitive to cold.

Last Spring Frost May 12
First Fall Frost October 8

Hard Freeze (28°F)

Last Spring Hard Freeze April 19
First Fall Hard Freeze November 4
53.87°N, -166.53°W © OpenStreetMap

Growing Season

165 Days May 6 to October 18

USDA Hardiness Zone iHardiness zones indicate which perennial plants can survive winter in your area. For annual vegetables, frost dates and growing season length matter more than hardiness zone.

Zone 8a

Avg. annual minimum: 10 to 15°F (−12 to −9°C)

Learn more

Köppen Climate iThe Köppen climate classification system categorizes climates based on temperature and precipitation patterns.

ET Tundra

No true summer — the warmest month averages below 10°C (50°F). Growing is limited to hardy greens, root crops, and cold-frames during the brief warm period. Permafrost restricts root depth.

Köppen climate map

Temperature

20° 30° 40° 50° 60°
33°
High: 37°F
Avg: 33°F
Low: 29°F
Jan
34°
High: 39°F
Avg: 34°F
Low: 29°F
Feb
34°
High: 39°F
Avg: 34°F
Low: 29°F
Mar
37°
High: 42°F
Avg: 37°F
Low: 33°F
Apr
42°
High: 47°F
Avg: 42°F
Low: 37°F
May
47°
High: 52°F
Avg: 47°F
Low: 42°F
Jun
52°
High: 57°F
Avg: 52°F
Low: 47°F
Jul
54°
High: 59°F
Avg: 54°F
Low: 48°F
Aug
49°
High: 55°F
Avg: 49°F
Low: 44°F
Sep
43°
High: 48°F
Avg: 43°F
Low: 38°F
Oct
38°
High: 43°F
Avg: 38°F
Low: 33°F
Nov
35°
High: 39°F
Avg: 35°F
Low: 31°F
Dec
32°F
28°F
Avg High Avg Temp Avg Low Light Frost (32°F) Hard Frost (28°F)

Precipitation

0" 2" 4" 4.9"
4.5"
4.49"
Jan
3.5"
3.51"
Feb
3.3"
3.28"
Mar
2.6"
2.58"
Apr
2.7"
2.66"
May
2.3"
2.27"
Jun
2.2"
2.23"
Jul
2.7"
2.74"
Aug
3.6"
3.62"
Sep
4.3"
4.34"
Oct
4.2"
4.15"
Nov
4.9"
4.86"
Dec

Sunrise / Sunset

4a7a10a1p4p7p10pNoonJanFebMarAprMayJunJulAugSepOctNovDec7.5h9.5h11.5h14h15.5h17h16.5h14.5h12.5h10h8h7h
Jan: 8:09 AM – 3:51 PM · 7h 42m
Feb: 7:16 AM – 4:44 PM · 9h 29m
Mar: 6:15 AM – 5:45 PM · 11h 29m
Apr: 5:07 AM – 6:53 PM · 13h 45m
May: 4:09 AM – 7:51 PM · 15h 42m
Jun: 3:35 AM – 8:25 PM · 16h 50m
Jul: 3:49 AM – 8:11 PM · 16h 22m
Aug: 4:41 AM – 7:19 PM · 14h 37m
Sep: 5:48 AM – 6:12 PM · 12h 24m
Oct: 6:54 AM – 5:06 PM · 10h 13m
Nov: 7:54 AM – 4:06 PM · 8h 13m
Dec: 8:25 AM – 3:35 PM · 7h 10m
Daylight Longest: 16h 52m · Shortest: 7h 08m

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