Frost dates for 55616Two Harbors, MN
The average last spring frost in Two Harbors is May 12 and the average first fall frost is October 6, giving a typical growing season of about 145 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 12
- Average first fall frost
- Oct 6
- Growing season
- 145 days
Safer after May 30 (1-in-10 risk)
Possible by Sep 19 (1-in-10 risk)
Last frost typically in 197 days
Frost risk by date
NOAA reports frost dates as probabilities. The middle date is the average (a 50% chance). For spring, the 10% date is a safer planting date: frost after it happens in about 1 year in 10. Light frost (36°F) can damage tender plants; a hard freeze (28°F) kills most annuals.
| Temperature | Last spring: 90% / 50% / 10% chance | First fall: 10% / 50% / 90% chance | Growing season (50%) | Years with at least one |
|---|---|---|---|---|
| Light frost (36°F) | May 14 · May 28 · Jun 11 | Sep 13 · Sep 27 · Oct 10 | 120 days | 100% |
| Frost / freeze (32°F) | Apr 30 · May 12 · May 30 | Sep 19 · Oct 6 · Oct 21 | 145 days | 100% |
| Hard freeze (28°F) | Apr 16 · Apr 29 · May 11 | Oct 1 · Oct 20 · Nov 4 | 174 days | 100% |
Planting calendar for Two Harbors
Planting windows from the University of Maryland Extension calendar, shifted to your average frost dates. Use them as a starting point and adjust for seed packet instructions and local conditions.
| Crop | Task | Window |
|---|---|---|
| Tomatoes | Start seeds indoors | Apr 11 – Jun 17 |
| Tomatoes | Transplant outdoors | May 28 – Jun 16 |
| Peppers | Start seeds indoors | Apr 11 – May 12 |
| Peppers | Transplant outdoors | Jun 11 – Jul 12 |
| Eggplant | Start seeds indoors | Apr 28 – May 27 |
| Eggplant | Transplant outdoors | Jun 11 – Jul 12 |
| Cucumbers | Sow outdoors | Jun 11 – Jun 26 |
| Summer squash | Sow outdoors | May 28 – Jul 12 |
| Winter squash & pumpkins | Sow outdoors | Jun 11 – Jul 12 |
| Snap beans | Sow outdoors | May 28 – Jul 19 |
| Sweet corn | Sow outdoors | May 28 – Jun 16 |
| Watermelon & cantaloupe | Sow outdoors | Jun 11 – Jul 12 |
| Okra | Sow outdoors | Jun 4 – Jun 27 |
| Peas | Sow outdoors (spring) | Apr 11 – May 27 |
| Potatoes | Plant outdoors (spring) | Apr 11 – Jun 11 |
| Onions | Start seeds indoors (spring) | Feb 28 – Mar 27 |
| Onions | Transplant outdoors (spring) | Apr 28 – May 27 |
| Broccoli | Start seeds indoors (spring) | Mar 24 – Apr 27 |
| Broccoli | Transplant outdoors (spring) | Apr 28 – May 27 |
| Broccoli | Start seeds indoors (fall) | Jun 6 – Jun 16 |
| Broccoli | Transplant outdoors (fall) | Jul 6 – Jul 17 |
| Cabbage | Start seeds indoors (spring) | Mar 14 – Apr 11 |
| Cabbage | Transplant outdoors (spring) | Apr 11 – May 12 |
| Cabbage | Start seeds indoors (fall) | May 27 – Jun 26 |
| Cabbage | Transplant outdoors (fall) | Jun 26 – Jul 27 |
| Leaf lettuce | Sow outdoors (spring) | Apr 11 – Jun 27 |
| Leaf lettuce | Sow outdoors (fall) | Jun 26 – Aug 12 |
| Spinach | Sow outdoors (spring) | Apr 4 – May 18 |
| Spinach | Sow outdoors (fall) | Jul 13 – Aug 17 |
| Radishes | Sow outdoors (spring) | Apr 11 – Jun 1 |
| Radishes | Sow outdoors (fall) | Jun 26 – Aug 27 |
| Kale | Sow outdoors (spring) | Apr 28 – May 18 |
| Kale | Sow outdoors (fall) | Jun 19 – Jul 27 |
| Carrots | Sow outdoors (spring) | May 12 – Jun 27 |
| Carrots | Sow outdoors (fall) | May 27 – Jul 12 |
| Garlic | Plant outdoors (fall) | Sep 26 – Oct 27 |
Where these dates come from
ZIP code 55616 is matched to the NOAA station Two Harbors, MN, 1.8 km away, at 625 ft elevation (205 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Two Harbors, MN (used) | 625 ft | May 12 | Oct 6 |
| Two Harbors 7Nw, MN | 1,355 ft | May 27 | Sep 23 |
| Brimson 2S, MN | 1,486 ft | — | — |
| Island Lake 4E, MN | 1,410 ft | May 21 | Sep 27 |
Frost dates near Two Harbors
- Knife River, MN 55609 · last May 12, first Oct 6
- Duluth, MN 55804 · last May 6, first Oct 9
- Brimson, MN 55602 · last —, first —
- Beaver Bay, MN 55601 · last May 15, first Oct 1
- Port Wing, WI 54865 · last May 31, first Oct 2
- Herbster, WI 54844 · last May 31, first Oct 2
- Maple, WI 54854 · last May 24, first Sep 26
- Superior, WI 54880 · last May 6, first Oct 9
Frequently asked questions
- When is the last frost in Two Harbors, MN?
- For ZIP code 55616, the average last spring frost (32°F) is May 12, based on NOAA 1991-2020 climate normals for the Two Harbors, MN weather station. There is a 1-in-10 chance of a frost after May 30.
- When is the first frost in Two Harbors, MN?
- The average first fall frost (32°F) is October 6. There is a 1-in-10 chance of frost by September 19, so tender plants are at risk from that point on.
- How long is the growing season in 55616?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 145 days long.
- Are these frost dates a forecast?
- No. They are 30-year averages and probabilities from NOAA weather station records. Use them to plan, then watch your local forecast before planting tender crops or leaving them uncovered.