Watertown, MN frost dates
Last spring frostApr 30median date
First fall frostOct 8median date
Growing season161 daysfrost-free
Hardiness zone4bZone 4b
How Watertown compares
- In 8 years out of 10, the last spring frost in Watertown falls between April 18 and May 14, a 26-day window. The first fall frost falls between September 24 and October 21.
- The median last frost is 5 days earlier than the Minnesota median of May 5.
- Its 161-day growing season is longer than 83% of the 801 Minnesota places with a regular frost season (state median 151 days).
- The last frost is 8 days earlier 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.
- Compared with Minnetonka, MN, 29 km away, the last frost here is 7 days later than there and the growing season is 13 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 18 |
| 50% (median) | April 30 |
| 10% (safe for tender plants) | May 14 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 24 |
| 50% (median) | October 8 |
| 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 Watertown, MN
Watertown, MN frost dates — last frost Apr 30, first frost Oct 8, zone 4b. whenisthelastfrost.com
Crop
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Start indoors: Feb 5 to Feb 19Transplant outside: Apr 2 to Apr 16
Start indoors: Feb 19 to Mar 5Transplant outside: May 14 to May 28
Start indoors: Feb 19 to Mar 5Transplant outside: May 14 to May 28
Start indoors: Mar 5 to Mar 19Transplant outside: May 7 to May 21
Start indoors: Mar 5 to Mar 19Transplant outside: Apr 9 to Apr 23Sow outdoors: Apr 2 to May 7Plant for fall: Aug 13 to Sep 10
Start indoors: Mar 5 to Mar 19Transplant outside: Apr 2 to Apr 16Sow outdoors: Apr 2 to Apr 16Plant for fall: Jul 30 to Aug 20
Start indoors: Mar 5 to Mar 19Transplant outside: Apr 16 to Apr 30Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 5 to Mar 19Transplant outside: Apr 9 to Apr 23Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 5 to Mar 19Transplant outside: Apr 16 to Apr 30Plant for fall: Jul 2 to Jul 23
Start indoors: Mar 19 to Apr 2Transplant outside: May 21 to Jun 4Sow outdoors: May 21 to Jun 4
Start indoors: Mar 19 to Apr 2Transplant outside: May 7 to May 21
Sow outdoors: Mar 19 to Apr 9Plant for fall: Jul 16 to Aug 6
Sow outdoors: Mar 19 to Apr 9Plant for fall: Aug 13 to Sep 3
Sow outdoors: Mar 26 to May 7Plant for fall: Aug 27 to Sep 17
Start indoors: Apr 2 to Apr 9Transplant outside: May 14 to May 21Sow outdoors: May 7 to May 21Plant for fall: Jul 23 to Aug 6
Start indoors: Apr 2 to Apr 9Sow outdoors: May 7 to May 21Plant for fall: Jul 30 to Aug 13
Start indoors: Apr 2 to Apr 9Sow outdoors: May 7 to May 21
Start indoors: Apr 2 to Apr 9Transplant outside: May 14 to May 28
Sow outdoors: Apr 9 to May 7Plant for fall: Jul 16 to Jul 30
Sow outdoors: Apr 9 to May 7Plant for fall: Jul 30 to Aug 13
Sow outdoors: Apr 9 to Apr 30
Sow outdoors: Apr 16 to May 14Plant for fall: Jul 30 to Aug 13
Sow outdoors: Apr 16 to May 7Plant for fall: Aug 13 to Sep 3
Sow outdoors: May 7 to May 28Plant for fall: Jul 23 to Aug 6
Sow outdoors: May 7 to May 21
Transplant outside: May 14 to Jun 4
Plant for fall: Sep 24 to Oct 29
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Watertown, MN
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 5 – Feb 19 | Apr 2 – Apr 16 | — | — |
| Peppers | Feb 19 – Mar 5 | May 14 – May 28 | — | — |
| Eggplant | Feb 19 – Mar 5 | May 14 – May 28 | — | — |
| Tomatoes | Mar 5 – Mar 19 | May 7 – May 21 | — | — |
| Lettuce | Mar 5 – Mar 19 | Apr 9 – Apr 23 | Apr 2 – May 7 | Aug 13 – Sep 10 |
| Kale | Mar 5 – Mar 19 | Apr 2 – Apr 16 | Apr 2 – Apr 16 | Jul 30 – Aug 20 |
| Broccoli | Mar 5 – Mar 19 | Apr 16 – Apr 30 | — | Jul 2 – Jul 23 |
| Cabbage | Mar 5 – Mar 19 | Apr 9 – Apr 23 | — | Jul 2 – Jul 23 |
| Cauliflower | Mar 5 – Mar 19 | Apr 16 – Apr 30 | — | Jul 2 – Jul 23 |
| Okra | Mar 19 – Apr 2 | May 21 – Jun 4 | May 21 – Jun 4 | — |
| Basil | Mar 19 – Apr 2 | May 7 – May 21 | — | — |
| Peas | — | — | Mar 19 – Apr 9 | Jul 16 – Aug 6 |
| Spinach | — | — | Mar 19 – Apr 9 | Aug 13 – Sep 3 |
| Radishes | — | — | Mar 26 – May 7 | Aug 27 – Sep 17 |
| Cucumbers | Apr 2 – Apr 9 | May 14 – May 21 | May 7 – May 21 | Jul 23 – Aug 6 |
| Zucchini & Summer Squash | Apr 2 – Apr 9 | — | May 7 – May 21 | Jul 30 – Aug 13 |
| Winter Squash & Pumpkins | Apr 2 – Apr 9 | — | May 7 – May 21 | — |
| Melons & Watermelon | Apr 2 – Apr 9 | May 14 – May 28 | — | — |
| Carrots | — | — | Apr 9 – May 7 | Jul 16 – Jul 30 |
| Beets | — | — | Apr 9 – May 7 | Jul 30 – Aug 13 |
| Potatoes | — | — | Apr 9 – Apr 30 | — |
| Swiss Chard | — | — | Apr 16 – May 14 | Jul 30 – Aug 13 |
| Cilantro | — | — | Apr 16 – May 7 | Aug 13 – Sep 3 |
| Green Beans | — | — | May 7 – May 28 | Jul 23 – Aug 6 |
| Sweet Corn | — | — | May 7 – May 21 | — |
| Sweet Potatoes | — | May 14 – Jun 4 | — | — |
| Garlic | — | — | — | Sep 24 – Oct 29 |
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 Delano, MN weather station, 11 km away (elevation 974 ft (297 m)).
Frost dates near Watertown
- Mayer Apr 30 · Oct 8
- Delano Apr 30 · Oct 8
- Saint Bonifacius May 5 · Oct 5
- Montrose Apr 30 · Oct 8
- New Germany Apr 30 · Oct 8
- Waconia May 5 · Oct 5
- Waverly Apr 30 · Oct 8
- Mound Apr 30 · Oct 9
- Winsted Apr 30 · Oct 10
- Spring Park Apr 30 · Oct 9
Frequently asked questions
When is the last frost in Watertown, MN?
The median last spring frost in Watertown, MN is April 30. There is still about a 10% chance of frost after May 14, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Watertown, MN?
The median first fall frost is October 8, with about a 10% chance of frost before September 24.
How long is the growing season in Watertown, MN?
About 161 days between the median last spring frost and first fall frost.
What planting zone is Watertown, MN?
Watertown, MN is in USDA hardiness zone 4b.