Frost Dates for Duluth Harbor Stn, MN

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 14
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 12
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 22
First Fall Frost October 5

Hard Freeze (28°F / -2°C)

Last Spring Hard Freeze April 29
First Fall Hard Freeze October 25
46.77°N, -92.09°W © OpenStreetMap

Growing Season

151 Days May 14 to October 12

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 4a

Learn more

Temperature

0° 20° 40° 60° 80°
13°
High: 21°
Avg: 13°
Low: 4°
Jan
17°
High: 26°
Avg: 17°
Low: 8°
Feb
27°
High: 35°
Avg: 27°
Low: 19°
Mar
38°
High: 45°
Avg: 38°
Low: 31°
Apr
49°
High: 56°
Avg: 49°
Low: 41°
May
58°
High: 66°
Avg: 58°
Low: 49°
Jun
67°
High: 75°
Avg: 67°
Low: 58°
Jul
67°
High: 74°
Avg: 67°
Low: 60°
Aug
59°
High: 66°
Avg: 59°
Low: 51°
Sep
45°
High: 52°
Avg: 45°
Low: 39°
Oct
32°
High: 39°
Avg: 32°
Low: 26°
Nov
20°
High: 27°
Avg: 20°
Low: 13°
Dec
32°F
28°F
Avg High Avg Temp Avg Low Light Frost (32°F) Hard Frost (28°F)

Precipitation

0" 2" 4" 6" 6.4"
2.4"
2.36"
Jan
2.7"
2.66"
Feb
3.6"
3.60"
Mar
4.4"
4.36"
Apr
4.8"
4.85"
May
6.0"
5.97"
Jun
5.9"
5.94"
Jul
6.4"
6.37"
Aug
5.3"
5.33"
Sep
4.5"
4.49"
Oct
3.2"
3.19"
Nov
2.6"
2.59"
Dec

Sunrise / Sunset

4a7a10a1p4p7p10pNoonJanFebMarAprMayJunJulAugSepOctNovDec9h10h12h13h15h16h15h14h12h11h9h8h
Jan: 7:38 AM – 4:22 PM · 8h 44m
Feb: 6:58 AM – 5:02 PM · 10h 04m
Mar: 6:12 AM – 5:48 PM · 11h 36m
Apr: 5:19 AM – 6:41 PM · 13h 21m
May: 4:35 AM – 7:25 PM · 14h 50m
Jun: 4:11 AM – 7:49 PM · 15h 38m
Jul: 4:21 AM – 7:39 PM · 15h 18m
Aug: 4:59 AM – 7:01 PM · 14h 01m
Sep: 5:51 AM – 6:09 PM · 12h 19m
Oct: 6:41 AM – 5:19 PM · 10h 37m
Nov: 7:27 AM – 4:33 PM · 9h 07m
Dec: 7:49 AM – 4:11 PM · 8h 21m
Daylight Longest: 15h 40m · Shortest: 8h 20m

Nearby Stations

Superior, WIMay 6 - October 9 Duluth, MNMay 13 - October 1 Duluth NWS, MNMay 18 - October 1 Pattison Ranger Staion, WI May 18 - October 3 Island Lake 4e, MN May 21 - September 27 Cloquet, MNMay 26 - September 23

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