Flensburg, MN frost dates
Last spring frostMay 4median date
First fall frostOct 5median date
Growing season154 daysfrost-free
Hardiness zone4aZone 4a
How Flensburg compares
- In 8 years out of 10, the last spring frost in Flensburg falls between April 21 and May 22, a 31-day window. The first fall frost falls between September 22 and October 19.
- The median last frost is 1 day earlier than the Minnesota median of May 5.
- Its 154-day growing season is longer than 60% of the 801 Minnesota places with a regular frost season (state median 151 days).
- The last frost is 8 days earlier than the zone 4a median of May 12. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 4a chart.
- The weather station records an average of 167 nights a year at or below 32°F.
- Compared with Saint Cloud, MN, 53 km away, the last frost here is 3 days earlier than there and the growing season is 8 days longer.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 21 |
| 50% (median) | May 4 |
| 10% (safe for tender plants) | May 22 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 22 |
| 50% (median) | October 5 |
| 90% (late) | October 19 |
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 Flensburg, MN
Flensburg, MN frost dates — last frost May 4, first frost Oct 5, zone 4a. whenisthelastfrost.com
Crop
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Start indoors: Feb 9 to Feb 23Transplant outside: Apr 6 to Apr 20
Start indoors: Feb 23 to Mar 9Transplant outside: May 18 to Jun 1
Start indoors: Feb 23 to Mar 9Transplant outside: May 18 to Jun 1
Start indoors: Mar 9 to Mar 23Transplant outside: May 11 to May 25
Start indoors: Mar 9 to Mar 23Transplant outside: Apr 13 to Apr 27Sow outdoors: Apr 6 to May 11Plant for fall: Aug 10 to Sep 7
Start indoors: Mar 9 to Mar 23Transplant outside: Apr 6 to Apr 20Sow outdoors: Apr 6 to Apr 20Plant for fall: Jul 27 to Aug 17
Start indoors: Mar 9 to Mar 23Transplant outside: Apr 20 to May 4Plant for fall: Jun 29 to Jul 20
Start indoors: Mar 9 to Mar 23Transplant outside: Apr 13 to Apr 27Plant for fall: Jun 29 to Jul 20
Start indoors: Mar 9 to Mar 23Transplant outside: Apr 20 to May 4Plant for fall: Jun 29 to Jul 20
Start indoors: Mar 23 to Apr 6Transplant outside: May 25 to Jun 8Sow outdoors: May 25 to Jun 8
Start indoors: Mar 23 to Apr 6Transplant outside: May 11 to May 25
Sow outdoors: Mar 23 to Apr 13Plant for fall: Jul 13 to Aug 3
Sow outdoors: Mar 23 to Apr 13Plant for fall: Aug 10 to Aug 31
Sow outdoors: Mar 30 to May 11Plant for fall: Aug 24 to Sep 14
Start indoors: Apr 6 to Apr 13Transplant outside: May 18 to May 25Sow outdoors: May 11 to May 25Plant for fall: Jul 20 to Aug 3
Start indoors: Apr 6 to Apr 13Sow outdoors: May 11 to May 25Plant for fall: Jul 27 to Aug 10
Start indoors: Apr 6 to Apr 13Sow outdoors: May 11 to May 25
Start indoors: Apr 6 to Apr 13Transplant outside: May 18 to Jun 1
Sow outdoors: Apr 13 to May 11Plant for fall: Jul 13 to Jul 27
Sow outdoors: Apr 13 to May 11Plant for fall: Jul 27 to Aug 10
Sow outdoors: Apr 13 to May 4
Sow outdoors: Apr 20 to May 18Plant for fall: Jul 27 to Aug 10
Sow outdoors: Apr 20 to May 11Plant for fall: Aug 10 to Aug 31
Sow outdoors: May 11 to Jun 1Plant for fall: Jul 20 to Aug 3
Sow outdoors: May 11 to May 25
Transplant outside: May 18 to Jun 8
Plant for fall: Sep 21 to Oct 26
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Flensburg, MN
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 9 – Feb 23 | Apr 6 – Apr 20 | — | — |
| Peppers | Feb 23 – Mar 9 | May 18 – Jun 1 | — | — |
| Eggplant | Feb 23 – Mar 9 | May 18 – Jun 1 | — | — |
| Tomatoes | Mar 9 – Mar 23 | May 11 – May 25 | — | — |
| Lettuce | Mar 9 – Mar 23 | Apr 13 – Apr 27 | Apr 6 – May 11 | Aug 10 – Sep 7 |
| Kale | Mar 9 – Mar 23 | Apr 6 – Apr 20 | Apr 6 – Apr 20 | Jul 27 – Aug 17 |
| Broccoli | Mar 9 – Mar 23 | Apr 20 – May 4 | — | Jun 29 – Jul 20 |
| Cabbage | Mar 9 – Mar 23 | Apr 13 – Apr 27 | — | Jun 29 – Jul 20 |
| Cauliflower | Mar 9 – Mar 23 | Apr 20 – May 4 | — | Jun 29 – Jul 20 |
| Okra | Mar 23 – Apr 6 | May 25 – Jun 8 | May 25 – Jun 8 | — |
| Basil | Mar 23 – Apr 6 | May 11 – May 25 | — | — |
| Peas | — | — | Mar 23 – Apr 13 | Jul 13 – Aug 3 |
| Spinach | — | — | Mar 23 – Apr 13 | Aug 10 – Aug 31 |
| Radishes | — | — | Mar 30 – May 11 | Aug 24 – Sep 14 |
| Cucumbers | Apr 6 – Apr 13 | May 18 – May 25 | May 11 – May 25 | Jul 20 – Aug 3 |
| Zucchini & Summer Squash | Apr 6 – Apr 13 | — | May 11 – May 25 | Jul 27 – Aug 10 |
| Winter Squash & Pumpkins | Apr 6 – Apr 13 | — | May 11 – May 25 | — |
| Melons & Watermelon | Apr 6 – Apr 13 | May 18 – Jun 1 | — | — |
| Carrots | — | — | Apr 13 – May 11 | Jul 13 – Jul 27 |
| Beets | — | — | Apr 13 – May 11 | Jul 27 – Aug 10 |
| Potatoes | — | — | Apr 13 – May 4 | — |
| Swiss Chard | — | — | Apr 20 – May 18 | Jul 27 – Aug 10 |
| Cilantro | — | — | Apr 20 – May 11 | Aug 10 – Aug 31 |
| Green Beans | — | — | May 11 – Jun 1 | Jul 20 – Aug 3 |
| Sweet Corn | — | — | May 11 – May 25 | — |
| Sweet Potatoes | — | May 18 – Jun 8 | — | — |
| Garlic | — | — | — | Sep 21 – Oct 26 |
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 Little Falls 2nne, MN weather station, 16 km away (elevation 1,119 ft (341 m)).
Frost dates near Flensburg
- Swanville May 13 · Sep 27
- Randall May 4 · Oct 5
- Little Falls May 4 · Oct 5
- Burtrum May 13 · Sep 27
- Upsala May 4 · Oct 1
- Bowlus May 10 · Sep 29
- Grey Eagle May 4 · Oct 1
- Long Prairie May 13 · Sep 27
- Holdingford May 3 · Oct 7
- Royalton May 10 · Sep 29
Frequently asked questions
When is the last frost in Flensburg, MN?
The median last spring frost in Flensburg, MN is May 4. There is still about a 10% chance of frost after May 22, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Flensburg, MN?
The median first fall frost is October 5, with about a 10% chance of frost before September 22.
How long is the growing season in Flensburg, MN?
About 154 days between the median last spring frost and first fall frost.
What planting zone is Flensburg, MN?
Flensburg, MN is in USDA hardiness zone 4a.