St. Paul, Minnesota: planting zone & frost dates
St. Paul is in USDA plant hardiness zone 5a, where the average coldest winter night reaches -20 to -15°F (-28.9 to -26.1°C). The typical last spring frost is around May 1 and the first fall frost around Oct 7.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | May 9 | Oct 1 |
| Typical planning date (30% risk) | May 1 | Oct 7 |
| Median (50%) | Apr 25 | Oct 12 |
How to read this: after the spring "10% risk" date, a 32°F frost happens in only about 1 year in 10. In fall, the "10% risk" date is the early end — a frost before it happens about 1 year in 10.
Frost data comes from NOAA station ST PAUL 3SW, MN (USC00217379), 2.7 mi (4.4 km) from the city center and 82 ft higher than the city center (+25 m). Record used for the 1991–2020 normals: 11 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across St. Paul
All 13 ZIP codes covering St. Paul are in zone 5a.
Vegetable planting calendar for St. Paul
Dates are counted from the 30%-risk frost dates above (last frost May 1, first frost Oct 7). Shift a week later in cold spots or low-lying ground.
| Crop | Start indoors | Transplant / plant out | Direct sow | Fall crop sow/plant |
|---|---|---|---|---|
| Tomato | Mar 6 – Mar 20 | May 8 – May 22 | — | — |
| Pepper | Feb 20 – Mar 6 | May 15 – May 29 | — | — |
| Lettuce | Mar 20 – Apr 3 | Apr 17 – May 8 | Apr 3 – May 15 | Jul 29 – Aug 26 |
| Green Beans | — | — | May 8 – Jun 12 | Jul 15 – Jul 29 |
| Sweet Corn | — | — | May 8 – Jun 5 | — |
| Zucchini & Summer Squash | Apr 3 – Apr 10 | May 8 – May 22 | May 8 – May 29 | Jul 15 – Jul 29 |
| Cucumber | Apr 3 – Apr 10 | May 15 – May 22 | May 8 – May 29 | Jul 15 – Jul 29 |
| Carrot | — | — | Apr 10 – May 15 | Jul 15 – Jul 29 |
| Onion | Feb 6 – Feb 20 | Apr 3 – Apr 17 | — | — |
| Potato | — | Apr 3 – Apr 24 | — | — |
| Basil | Mar 20 – Apr 3 | May 15 – May 29 | May 15 – Jun 5 | — |
| Spinach | — | — | Mar 20 – Apr 17 | Aug 12 – Sep 9 |
| Kale | Mar 6 – Mar 20 | Apr 3 – Apr 24 | Apr 3 – Apr 24 | Jul 29 – Aug 26 |
| Broccoli | Mar 6 – Mar 20 | Apr 17 – May 8 | — | Jul 15 – Jul 29 |
| Peas | — | — | Mar 20 – Apr 10 | Jul 29 – Aug 12 |
| Eggplant | Feb 20 – Mar 6 | May 15 – May 29 | — | — |
| Cabbage | Mar 6 – Mar 20 | Apr 3 – Apr 17 | — | Jul 15 – Jul 29 |
| Radish | — | — | Mar 27 – May 15 | Aug 26 – Sep 23 |
| Strawberry | — | Apr 3 – Apr 24 | — | — |
| Beets | — | — | Apr 10 – May 22 | Jul 29 – Aug 12 |
Nearby cities in Minnesota
- Minneapolis — zone 5a, last frost Apr 30, first frost Oct 10
- Woodbury — zone 5a, last frost May 1, first frost Oct 5
- Bloomington — zone 5a, last frost Apr 30, first frost Oct 11
- Brooklyn Park — zone 5a, last frost May 6, first frost Oct 2
- Lakeville — zone 4b, last frost May 2, first frost Oct 4
- Plymouth — zone 5a, last frost May 4, first frost Oct 5
More: all Minnesota cities · other zone 5a cities: Minneapolis, MN, Anchorage, AK, Sioux Falls, SD, Cedar Rapids, IA, Billings, MT, Bloomington, MN, Sioux City, IA, Brooklyn Park, MN
St. Paul gardening questions
When is the last frost in St. Paul, MN?
Plan around May 1. At NOAA's St Paul 3SW, MN station, 2.7 mi from the city center, there is a 30% chance of a 32°F frost after that date. Half of springs have their last frost by Apr 25, and after May 9 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Apr 12. The 90% and 10% dates are 30 days apart, close to the 36-day median for cities on this site.
When should I plant tomatoes in St. Paul, MN?
Start seeds indoors Mar 6 – Mar 20 and set transplants outside May 8 – May 22, once nights stay above 50°F and the soil is near 60°F. That leaves 159 days between the 30% frost dates, enough for most varieties including 80–85-day slicers. More: tomato planting dates by zone.
How long is the growing season in St. Paul?
About 169 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 149 days, and in 1 year in 10 it runs 188 days or more. In fall there is a 10% chance of frost by Oct 1 and a 30% chance by Oct 7. That ranks 3rd longest of 9 Minnesota cities on this site.
When should I plant a fall garden in St. Paul?
Count back from the first fall frost (Oct 7): transplant broccoli Jul 15 – Jul 29; sow kale Jul 29 – Aug 26; sow lettuce Jul 29 – Aug 26; sow radishes Aug 26 – Sep 23. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Oct 23. How the math works: succession and fall planting.
Did St. Paul's hardiness zone change on the 2023 map?
Yes. Most of St. Paul was zone 4b on the 2012 map and is zone 5a on the 2023 map — half a zone warmer, like about 56% of U.S. ZIP codes. The shift comes from a newer 1991–2020 averaging period plus more weather stations and better mapping; it does not mean last frost comes earlier. Why the 2023 map is warmer.
How does St. Paul compare with Minneapolis, MN?
Both are in zone 5a. The typical last spring frost in St. Paul (May 1) comes about the same time as in Minneapolis, MN (Apr 30), 8 miles away, and the first fall frost is Oct 7 versus Oct 10. The two cities use different NOAA stations.