Frost dates for 55815 — Duluth, MN
Last spring frostMay 14median date
First fall frostOct 12median date
Growing season151 daysfrost-free
Hardiness zone4bZone 4b
How Duluth compares
- In 8 years out of 10, the last spring frost in Duluth falls between April 24 and June 1, a 38-day window. The first fall frost falls between September 25 and October 26.
- The median last frost is 9 days later than the Minnesota median of May 5.
- Its 151-day growing season is longer than 48% of the 801 Minnesota places with a regular frost season (state median 151 days).
- The last frost is 6 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 166 nights a year at or below 32°F.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 24 |
| 50% (median) | May 14 |
| 10% (safe for tender plants) | June 1 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 25 |
| 50% (median) | October 12 |
| 90% (late) | October 26 |
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 55815 — Duluth, MN — last frost May 14, first frost Oct 12, zone 4b. whenisthelastfrost.com
Crop
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Start indoors: Feb 19 to Mar 5Transplant outside: Apr 16 to Apr 30
Start indoors: Mar 5 to Mar 19Transplant outside: May 28 to Jun 11
Start indoors: Mar 5 to Mar 19Transplant outside: May 28 to Jun 11
Start indoors: Mar 19 to Apr 2Transplant outside: May 21 to Jun 4
Start indoors: Mar 19 to Apr 2Transplant outside: Apr 23 to May 7Sow outdoors: Apr 16 to May 21Plant for fall: Aug 17 to Sep 14
Start indoors: Mar 19 to Apr 2Transplant outside: Apr 16 to Apr 30Sow outdoors: Apr 16 to Apr 30Plant for fall: Aug 3 to Aug 24
Start indoors: Mar 19 to Apr 2Transplant outside: Apr 30 to May 14Plant for fall: Jul 6 to Jul 27
Start indoors: Mar 19 to Apr 2Transplant outside: Apr 23 to May 7Plant for fall: Jul 6 to Jul 27
Start indoors: Mar 19 to Apr 2Transplant outside: Apr 30 to May 14Plant for fall: Jul 6 to Jul 27
Start indoors: Apr 2 to Apr 16Transplant outside: Jun 4 to Jun 18Sow outdoors: Jun 4 to Jun 18
Start indoors: Apr 2 to Apr 16Transplant outside: May 21 to Jun 4
Sow outdoors: Apr 2 to Apr 23Plant for fall: Jul 20 to Aug 10
Sow outdoors: Apr 2 to Apr 23Plant for fall: Aug 17 to Sep 7
Sow outdoors: Apr 9 to May 21Plant for fall: Aug 31 to Sep 21
Start indoors: Apr 16 to Apr 23Transplant outside: May 28 to Jun 4Sow outdoors: May 21 to Jun 4Plant for fall: Jul 27 to Aug 10
Start indoors: Apr 16 to Apr 23Sow outdoors: May 21 to Jun 4Plant for fall: Aug 3 to Aug 17
Start indoors: Apr 16 to Apr 23Sow outdoors: May 21 to Jun 4
Start indoors: Apr 16 to Apr 23Transplant outside: May 28 to Jun 11
Sow outdoors: Apr 23 to May 21Plant for fall: Jul 20 to Aug 3
Sow outdoors: Apr 23 to May 21Plant for fall: Aug 3 to Aug 17
Sow outdoors: Apr 23 to May 14
Sow outdoors: Apr 30 to May 28Plant for fall: Aug 3 to Aug 17
Sow outdoors: Apr 30 to May 21Plant for fall: Aug 17 to Sep 7
Sow outdoors: May 21 to Jun 11Plant for fall: Jul 27 to Aug 10
Sow outdoors: May 21 to Jun 4
Transplant outside: May 28 to Jun 18
Plant for fall: Sep 28 to Nov 2
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 19 – Mar 5 | Apr 16 – Apr 30 | — | — |
| Peppers | Mar 5 – Mar 19 | May 28 – Jun 11 | — | — |
| Eggplant | Mar 5 – Mar 19 | May 28 – Jun 11 | — | — |
| Tomatoes | Mar 19 – Apr 2 | May 21 – Jun 4 | — | — |
| Lettuce | Mar 19 – Apr 2 | Apr 23 – May 7 | Apr 16 – May 21 | Aug 17 – Sep 14 |
| Kale | Mar 19 – Apr 2 | Apr 16 – Apr 30 | Apr 16 – Apr 30 | Aug 3 – Aug 24 |
| Broccoli | Mar 19 – Apr 2 | Apr 30 – May 14 | — | Jul 6 – Jul 27 |
| Cabbage | Mar 19 – Apr 2 | Apr 23 – May 7 | — | Jul 6 – Jul 27 |
| Cauliflower | Mar 19 – Apr 2 | Apr 30 – May 14 | — | Jul 6 – Jul 27 |
| Okra | Apr 2 – Apr 16 | Jun 4 – Jun 18 | Jun 4 – Jun 18 | — |
| Basil | Apr 2 – Apr 16 | May 21 – Jun 4 | — | — |
| Peas | — | — | Apr 2 – Apr 23 | Jul 20 – Aug 10 |
| Spinach | — | — | Apr 2 – Apr 23 | Aug 17 – Sep 7 |
| Radishes | — | — | Apr 9 – May 21 | Aug 31 – Sep 21 |
| Cucumbers | Apr 16 – Apr 23 | May 28 – Jun 4 | May 21 – Jun 4 | Jul 27 – Aug 10 |
| Zucchini & Summer Squash | Apr 16 – Apr 23 | — | May 21 – Jun 4 | Aug 3 – Aug 17 |
| Winter Squash & Pumpkins | Apr 16 – Apr 23 | — | May 21 – Jun 4 | — |
| Melons & Watermelon | Apr 16 – Apr 23 | May 28 – Jun 11 | — | — |
| Carrots | — | — | Apr 23 – May 21 | Jul 20 – Aug 3 |
| Beets | — | — | Apr 23 – May 21 | Aug 3 – Aug 17 |
| Potatoes | — | — | Apr 23 – May 14 | — |
| Swiss Chard | — | — | Apr 30 – May 28 | Aug 3 – Aug 17 |
| Cilantro | — | — | Apr 30 – May 21 | Aug 17 – Sep 7 |
| Green Beans | — | — | May 21 – Jun 11 | Jul 27 – Aug 10 |
| Sweet Corn | — | — | May 21 – Jun 4 | — |
| Sweet Potatoes | — | May 28 – Jun 18 | — | — |
| Garlic | — | — | — | Sep 28 – Nov 2 |
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 Harbor Stn, MN weather station, 2 km away (elevation 610 ft (186 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
- Twig May 18 · Oct 1
- Saginaw May 18 · Oct 1
- Wrenshall Jun 1 · Sep 22
- Knife River May 12 · Oct 6
- Carlton May 26 · Sep 23
- Cloquet 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 14. There is still about a 10% chance of frost after June 1, 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 12, with about a 10% chance of frost before September 25.
How long is the growing season in Duluth, MN?
About 151 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.