Frost dates for 55810 — Duluth, MN
Last spring frostMay 18median date
First fall frostOct 1median date
Growing season136 daysfrost-free
Hardiness zone4bZone 4b
How Duluth compares
- In 8 years out of 10, the last spring frost in Duluth falls between May 2 and June 3, a 32-day window. The first fall frost falls between September 19 and October 14.
- The median last frost is 13 days later than the Minnesota median of May 5.
- Its 136-day growing season is longer than 15% of the 801 Minnesota places with a regular frost season (state median 151 days).
- The last frost is 10 days later than the zone 4b median of May 8. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 4b chart.
- The weather station records an average of 184 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | May 2 |
| 50% (median) | May 18 |
| 10% (safe for tender plants) | June 3 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 19 |
| 50% (median) | October 1 |
| 90% (late) | October 14 |
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 Duluth, MN
Frost dates for 55810 — Duluth, MN — last frost May 18, first frost Oct 1, zone 4b. whenisthelastfrost.com
Crop
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Start indoors: Feb 23 to Mar 9Transplant outside: Apr 20 to May 4
Start indoors: Mar 9 to Mar 23Transplant outside: Jun 1 to Jun 15
Start indoors: Mar 9 to Mar 23Transplant outside: Jun 1 to Jun 15
Start indoors: Mar 23 to Apr 6Transplant outside: May 25 to Jun 8
Start indoors: Mar 23 to Apr 6Transplant outside: Apr 27 to May 11Sow outdoors: Apr 20 to May 25Plant for fall: Aug 6 to Sep 3
Start indoors: Mar 23 to Apr 6Transplant outside: Apr 20 to May 4Sow outdoors: Apr 20 to May 4Plant for fall: Jul 23 to Aug 13
Start indoors: Mar 23 to Apr 6Transplant outside: May 4 to May 18Plant for fall: Jun 25 to Jul 16
Start indoors: Mar 23 to Apr 6Transplant outside: Apr 27 to May 11Plant for fall: Jun 25 to Jul 16
Start indoors: Mar 23 to Apr 6Transplant outside: May 4 to May 18Plant for fall: Jun 25 to Jul 16
Start indoors: Apr 6 to Apr 20Transplant outside: Jun 8 to Jun 22Sow outdoors: Jun 8 to Jun 22
Start indoors: Apr 6 to Apr 20Transplant outside: May 25 to Jun 8
Sow outdoors: Apr 6 to Apr 27Plant for fall: Jul 9 to Jul 30
Sow outdoors: Apr 6 to Apr 27Plant for fall: Aug 6 to Aug 27
Sow outdoors: Apr 13 to May 25Plant for fall: Aug 20 to Sep 10
Start indoors: Apr 20 to Apr 27Transplant outside: Jun 1 to Jun 8Sow outdoors: May 25 to Jun 8Plant for fall: Jul 16 to Jul 30
Start indoors: Apr 20 to Apr 27Sow outdoors: May 25 to Jun 8Plant for fall: Jul 23 to Aug 6
Start indoors: Apr 20 to Apr 27Sow outdoors: May 25 to Jun 8
Start indoors: Apr 20 to Apr 27Transplant outside: Jun 1 to Jun 15
Sow outdoors: Apr 27 to May 25Plant for fall: Jul 9 to Jul 23
Sow outdoors: Apr 27 to May 25Plant for fall: Jul 23 to Aug 6
Sow outdoors: Apr 27 to May 18
Sow outdoors: May 4 to Jun 1Plant for fall: Jul 23 to Aug 6
Sow outdoors: May 4 to May 25Plant for fall: Aug 6 to Aug 27
Sow outdoors: May 25 to Jun 15Plant for fall: Jul 16 to Jul 30
Sow outdoors: May 25 to Jun 8
Transplant outside: Jun 1 to Jun 22
Plant for fall: Sep 17 to Oct 22
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Duluth, MN
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 23 – Mar 9 | Apr 20 – May 4 | — | — |
| Peppers | Mar 9 – Mar 23 | Jun 1 – Jun 15 | — | — |
| Eggplant | Mar 9 – Mar 23 | Jun 1 – Jun 15 | — | — |
| Tomatoes | Mar 23 – Apr 6 | May 25 – Jun 8 | — | — |
| Lettuce | Mar 23 – Apr 6 | Apr 27 – May 11 | Apr 20 – May 25 | Aug 6 – Sep 3 |
| Kale | Mar 23 – Apr 6 | Apr 20 – May 4 | Apr 20 – May 4 | Jul 23 – Aug 13 |
| Broccoli | Mar 23 – Apr 6 | May 4 – May 18 | — | Jun 25 – Jul 16 |
| Cabbage | Mar 23 – Apr 6 | Apr 27 – May 11 | — | Jun 25 – Jul 16 |
| Cauliflower | Mar 23 – Apr 6 | May 4 – May 18 | — | Jun 25 – Jul 16 |
| Okra | Apr 6 – Apr 20 | Jun 8 – Jun 22 | Jun 8 – Jun 22 | — |
| Basil | Apr 6 – Apr 20 | May 25 – Jun 8 | — | — |
| Peas | — | — | Apr 6 – Apr 27 | Jul 9 – Jul 30 |
| Spinach | — | — | Apr 6 – Apr 27 | Aug 6 – Aug 27 |
| Radishes | — | — | Apr 13 – May 25 | Aug 20 – Sep 10 |
| Cucumbers | Apr 20 – Apr 27 | Jun 1 – Jun 8 | May 25 – Jun 8 | Jul 16 – Jul 30 |
| Zucchini & Summer Squash | Apr 20 – Apr 27 | — | May 25 – Jun 8 | Jul 23 – Aug 6 |
| Winter Squash & Pumpkins | Apr 20 – Apr 27 | — | May 25 – Jun 8 | — |
| Melons & Watermelon | Apr 20 – Apr 27 | Jun 1 – Jun 15 | — | — |
| Carrots | — | — | Apr 27 – May 25 | Jul 9 – Jul 23 |
| Beets | — | — | Apr 27 – May 25 | Jul 23 – Aug 6 |
| Potatoes | — | — | Apr 27 – May 18 | — |
| Swiss Chard | — | — | May 4 – Jun 1 | Jul 23 – Aug 6 |
| Cilantro | — | — | May 4 – May 25 | Aug 6 – Aug 27 |
| Green Beans | — | — | May 25 – Jun 15 | Jul 16 – Jul 30 |
| Sweet Corn | — | — | May 25 – Jun 8 | — |
| Sweet Potatoes | — | Jun 1 – Jun 22 | — | — |
| Garlic | — | — | — | Sep 17 – Oct 22 |
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 Duluth Nws, MN weather station, 9 km away (elevation 1,434 ft (437 m)).
ZIP codes in Duluth: 55801 55802 55803 55804 55805 55806 55807 55808 55810 55811 55812 55814 55815 55816
Frost dates near Duluth
- Esko May 26 · Sep 23
- Saginaw May 18 · Oct 1
- Twig May 18 · Oct 1
- Carlton May 26 · Sep 23
- Wrenshall Jun 1 · Sep 22
- Cloquet May 26 · Sep 23
- Brookston May 26 · Sep 23
- Alborn May 27 · Sep 20
Frequently asked questions
When is the last frost in Duluth, MN?
The median last spring frost in Duluth, MN is May 18. There is still about a 10% chance of frost after June 3, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Duluth, MN?
The median first fall frost is October 1, with about a 10% chance of frost before September 19.
How long is the growing season in Duluth, MN?
About 136 days between the median last spring frost and first fall frost.
What planting zone is Duluth, MN?
Duluth, MN is in USDA hardiness zone 4b.