Two Harbors, MN frost dates
Last spring frostMay 12median date
First fall frostOct 6median date
Growing season147 daysfrost-free
Hardiness zone3bZone 3b
How Two Harbors compares
- In 8 years out of 10, the last spring frost in Two Harbors falls between April 30 and May 30, a 30-day window. The first fall frost falls between September 19 and October 21.
- The median last frost is 7 days later than the Minnesota median of May 5.
- Its 147-day growing season is longer than 37% of the 801 Minnesota places with a regular frost season (state median 151 days).
- The last frost is 5 days earlier than the zone 3b median of May 17. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 3b chart.
- The weather station records an average of 164 nights a year at or below 32°F.
- Compared with Duluth, MN, 44 km away, the last frost here is 2 days earlier than there and the growing season is 4 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 30 |
| 50% (median) | May 12 |
| 10% (safe for tender plants) | May 30 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 19 |
| 50% (median) | October 6 |
| 90% (late) | October 21 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Two Harbors, MN
Two Harbors, MN frost dates — last frost May 12, first frost Oct 6, zone 3b. whenisthelastfrost.com
Crop
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Start indoors: Feb 17 to Mar 3Transplant outside: Apr 14 to Apr 28
Start indoors: Mar 3 to Mar 17Transplant outside: May 26 to Jun 9
Start indoors: Mar 3 to Mar 17Transplant outside: May 26 to Jun 9
Start indoors: Mar 17 to Mar 31Transplant outside: May 19 to Jun 2
Start indoors: Mar 17 to Mar 31Transplant outside: Apr 21 to May 5Sow outdoors: Apr 14 to May 19Plant for fall: Aug 11 to Sep 8
Start indoors: Mar 17 to Mar 31Transplant outside: Apr 14 to Apr 28Sow outdoors: Apr 14 to Apr 28Plant for fall: Jul 28 to Aug 18
Start indoors: Mar 17 to Mar 31Transplant outside: Apr 28 to May 12Plant for fall: Jun 30 to Jul 21
Start indoors: Mar 17 to Mar 31Transplant outside: Apr 21 to May 5Plant for fall: Jun 30 to Jul 21
Start indoors: Mar 17 to Mar 31Transplant outside: Apr 28 to May 12Plant for fall: Jun 30 to Jul 21
Start indoors: Mar 31 to Apr 14Transplant outside: Jun 2 to Jun 16Sow outdoors: Jun 2 to Jun 16
Start indoors: Mar 31 to Apr 14Transplant outside: May 19 to Jun 2
Sow outdoors: Mar 31 to Apr 21Plant for fall: Jul 14 to Aug 4
Sow outdoors: Mar 31 to Apr 21Plant for fall: Aug 11 to Sep 1
Sow outdoors: Apr 7 to May 19Plant for fall: Aug 25 to Sep 15
Start indoors: Apr 14 to Apr 21Transplant outside: May 26 to Jun 2Sow outdoors: May 19 to Jun 2Plant for fall: Jul 21 to Aug 4
Start indoors: Apr 14 to Apr 21Sow outdoors: May 19 to Jun 2Plant for fall: Jul 28 to Aug 11
Start indoors: Apr 14 to Apr 21Sow outdoors: May 19 to Jun 2
Start indoors: Apr 14 to Apr 21Transplant outside: May 26 to Jun 9
Sow outdoors: Apr 21 to May 19Plant for fall: Jul 14 to Jul 28
Sow outdoors: Apr 21 to May 19Plant for fall: Jul 28 to Aug 11
Sow outdoors: Apr 21 to May 12
Sow outdoors: Apr 28 to May 26Plant for fall: Jul 28 to Aug 11
Sow outdoors: Apr 28 to May 19Plant for fall: Aug 11 to Sep 1
Sow outdoors: May 19 to Jun 9Plant for fall: Jul 21 to Aug 4
Sow outdoors: May 19 to Jun 2
Transplant outside: May 26 to Jun 16
Plant for fall: Sep 22 to Oct 27
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Two Harbors, MN
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 17 – Mar 3 | Apr 14 – Apr 28 | — | — |
| Peppers | Mar 3 – Mar 17 | May 26 – Jun 9 | — | — |
| Eggplant | Mar 3 – Mar 17 | May 26 – Jun 9 | — | — |
| Tomatoes | Mar 17 – Mar 31 | May 19 – Jun 2 | — | — |
| Lettuce | Mar 17 – Mar 31 | Apr 21 – May 5 | Apr 14 – May 19 | Aug 11 – Sep 8 |
| Kale | Mar 17 – Mar 31 | Apr 14 – Apr 28 | Apr 14 – Apr 28 | Jul 28 – Aug 18 |
| Broccoli | Mar 17 – Mar 31 | Apr 28 – May 12 | — | Jun 30 – Jul 21 |
| Cabbage | Mar 17 – Mar 31 | Apr 21 – May 5 | — | Jun 30 – Jul 21 |
| Cauliflower | Mar 17 – Mar 31 | Apr 28 – May 12 | — | Jun 30 – Jul 21 |
| Okra | Mar 31 – Apr 14 | Jun 2 – Jun 16 | Jun 2 – Jun 16 | — |
| Basil | Mar 31 – Apr 14 | May 19 – Jun 2 | — | — |
| Peas | — | — | Mar 31 – Apr 21 | Jul 14 – Aug 4 |
| Spinach | — | — | Mar 31 – Apr 21 | Aug 11 – Sep 1 |
| Radishes | — | — | Apr 7 – May 19 | Aug 25 – Sep 15 |
| Cucumbers | Apr 14 – Apr 21 | May 26 – Jun 2 | May 19 – Jun 2 | Jul 21 – Aug 4 |
| Zucchini & Summer Squash | Apr 14 – Apr 21 | — | May 19 – Jun 2 | Jul 28 – Aug 11 |
| Winter Squash & Pumpkins | Apr 14 – Apr 21 | — | May 19 – Jun 2 | — |
| Melons & Watermelon | Apr 14 – Apr 21 | May 26 – Jun 9 | — | — |
| Carrots | — | — | Apr 21 – May 19 | Jul 14 – Jul 28 |
| Beets | — | — | Apr 21 – May 19 | Jul 28 – Aug 11 |
| Potatoes | — | — | Apr 21 – May 12 | — |
| Swiss Chard | — | — | Apr 28 – May 26 | Jul 28 – Aug 11 |
| Cilantro | — | — | Apr 28 – May 19 | Aug 11 – Sep 1 |
| Green Beans | — | — | May 19 – Jun 9 | Jul 21 – Aug 4 |
| Sweet Corn | — | — | May 19 – Jun 2 | — |
| Sweet Potatoes | — | May 26 – Jun 16 | — | — |
| Garlic | — | — | — | Sep 22 – Oct 27 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Two Harbors, MN weather station, 2 km away (elevation 627 ft (191 m)).
Frost dates near Two Harbors
- Knife River May 12 · Oct 6
- Brimson frost any month
- Beaver Bay May 15 · Oct 1
- Duluth May 14 · Oct 12
- Silver Bay May 15 · Oct 1
- Twig May 18 · Oct 1
- Finland May 15 · Oct 1
- Saginaw May 18 · Oct 1
- Cotton May 27 · Sep 20
- Canyon May 27 · Sep 20
Frequently asked questions
When is the last frost in Two Harbors, MN?
The median last spring frost in Two Harbors, MN is May 12. There is still about a 10% chance of frost after May 30, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Two Harbors, MN?
The median first fall frost is October 6, with about a 10% chance of frost before September 19.
How long is the growing season in Two Harbors, MN?
About 147 days between the median last spring frost and first fall frost.
What planting zone is Two Harbors, MN?
Two Harbors, MN is in USDA hardiness zone 3b.