Rochester, Minnesota: planting zone & frost dates
Rochester is in USDA plant hardiness zone 4b, where the average coldest winter night reaches -25 to -20°F (-31.7 to -28.9°C). The typical last spring frost is around May 5 and the first fall frost around Oct 1.
Frost dates
| Probability | Last spring frost (32°F) | First fall frost (32°F) |
|---|---|---|
| Safer (10% risk) | May 13 | Sep 22 |
| Typical planning date (30% risk) | May 5 | Oct 1 |
| Median (50%) | Apr 30 | Oct 6 |
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 ROCHESTER INTL AP, MN (USW00014925), 7.6 mi (12.3 km) from the city center and 203 ft higher than the city center (+62 m). Record used for the 1991–2020 normals: 30 years.
Why your yard may differ from the station: microclimates.
Hardiness zone across Rochester
All 5 ZIP codes covering Rochester are in zone 4b.
Vegetable planting calendar for Rochester
Dates are counted from the 30%-risk frost dates above (last frost May 5, first frost Oct 1). 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 10 – Mar 24 | May 12 – May 26 | — | — |
| Pepper | Feb 24 – Mar 10 | May 19 – Jun 2 | — | — |
| Lettuce | Mar 24 – Apr 7 | Apr 21 – May 12 | Apr 7 – May 19 | Jul 23 – Aug 20 |
| Green Beans | — | — | May 12 – Jun 16 | Jul 9 – Jul 23 |
| Sweet Corn | — | — | May 12 – Jun 9 | — |
| Zucchini & Summer Squash | Apr 7 – Apr 14 | May 12 – May 26 | May 12 – Jun 2 | Jul 9 – Jul 23 |
| Cucumber | Apr 7 – Apr 14 | May 19 – May 26 | May 12 – Jun 2 | Jul 9 – Jul 23 |
| Carrot | — | — | Apr 14 – May 19 | Jul 9 – Jul 23 |
| Onion | Feb 10 – Feb 24 | Apr 7 – Apr 21 | — | — |
| Potato | — | Apr 7 – Apr 28 | — | — |
| Basil | Mar 24 – Apr 7 | May 19 – Jun 2 | May 19 – Jun 9 | — |
| Spinach | — | — | Mar 24 – Apr 21 | Aug 6 – Sep 3 |
| Kale | Mar 10 – Mar 24 | Apr 7 – Apr 28 | Apr 7 – Apr 28 | Jul 23 – Aug 20 |
| Broccoli | Mar 10 – Mar 24 | Apr 21 – May 12 | — | Jul 9 – Jul 23 |
| Peas | — | — | Mar 24 – Apr 14 | Jul 23 – Aug 6 |
| Eggplant | Feb 24 – Mar 10 | May 19 – Jun 2 | — | — |
| Cabbage | Mar 10 – Mar 24 | Apr 7 – Apr 21 | — | Jul 9 – Jul 23 |
| Radish | — | — | Mar 31 – May 19 | Aug 20 – Sep 17 |
| Strawberry | — | Apr 7 – Apr 28 | — | — |
| Beets | — | — | Apr 14 – May 26 | Jul 23 – Aug 6 |
Nearby cities in Minnesota
- Woodbury — zone 5a, last frost May 1, first frost Oct 5
- Lakeville — zone 4b, last frost May 2, first frost Oct 4
- St. Paul — zone 5a, last frost May 1, first frost Oct 7
- Bloomington — zone 5a, last frost Apr 30, first frost Oct 11
- Minneapolis — zone 5a, last frost Apr 30, first frost Oct 10
- Brooklyn Park — zone 5a, last frost May 6, first frost Oct 2
More: all Minnesota cities · other zone 4b cities: Duluth, MN, Lakeville, MN
Rochester gardening questions
When is the last frost in Rochester, MN?
Plan around May 5. At NOAA's Rochester Int'l Airport, MN station, 7.6 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 30, and after May 13 the risk drops to about 1 in 10. A hard freeze (28°F) usually ends earlier, around Apr 18. The last frost is fairly predictable here: only 28 days separate the 90% and 10% dates (median for cities on this site: 36 days).
When should I plant tomatoes in Rochester, MN?
Start seeds indoors Mar 10 – Mar 24 and set transplants outside May 12 – May 26, once nights stay above 50°F and the soil is near 60°F. That leaves 149 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 Rochester?
About 159 days without a 32°F frost in a typical (median) year. In 9 years out of 10 the season lasts at least 140 days, and in 1 year in 10 it runs 178 days or more. In fall there is a 10% chance of frost by Sep 22 and a 30% chance by Oct 1. That ranks 7th longest of 9 Minnesota cities on this site.
When should I plant a fall garden in Rochester?
Count back from the first fall frost (Oct 1): transplant broccoli Jul 9 – Jul 23; sow kale Jul 23 – Aug 20; sow lettuce Jul 23 – Aug 20; sow radishes Aug 20 – Sep 17. Hardy crops keep growing through light frosts; the median 28°F hard freeze here is Oct 17. How the math works: succession and fall planting.
Did Rochester's hardiness zone change on the 2023 map?
No. Going by the zone that covers most of the city's land, Rochester is zone 4b on both the 2012 and the 2023 USDA maps (PRISM/OSU ZIP listings). About 42% of U.S. ZIP codes kept their half-zone in 2023. Why the 2023 map is warmer.
How does Rochester compare with Lakeville, MN?
Both are in zone 4b. The typical last spring frost in Rochester (May 5) comes about the same time as in Lakeville, MN (May 2), 60 miles away, and the first fall frost is Oct 1 versus Oct 4. The two cities use different NOAA stations.