Frost dates for 58772Portal, ND
The average last spring frost in Portal is May 20 and the average first fall frost is September 19, giving a typical growing season of about 121 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 20
- Average first fall frost
- Sep 19
- Growing season
- 121 days
Safer after Jun 2 (1-in-10 risk)
Possible by Sep 7 (1-in-10 risk)
Last frost typically in 205 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 17 · May 29 · Jun 15 | Aug 25 · Sep 9 · Sep 20 | 101 days | 100% |
| Frost / freeze (32°F) | May 9 · May 20 · Jun 2 | Sep 7 · Sep 19 · Sep 28 | 121 days | 100% |
| Hard freeze (28°F) | Apr 29 · May 11 · May 24 | Sep 14 · Sep 26 · Oct 8 | 137 days | 100% |
Planting calendar for Portal
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 19 – Jun 25 |
| Tomatoes | Transplant outdoors | Jun 5 – May 30 |
| Peppers | Start seeds indoors | Apr 19 – May 20 |
| Peppers | Transplant outdoors | Jun 19 – Jul 20 |
| Eggplant | Start seeds indoors | May 6 – Jun 4 |
| Eggplant | Transplant outdoors | Jun 19 – Jul 20 |
| Cucumbers | Sow outdoors | Jun 19 – Jun 9 |
| Summer squash | Sow outdoors | Jun 5 – Jul 20 |
| Winter squash & pumpkins | Sow outdoors | Jun 19 – Jul 20 |
| Snap beans | Sow outdoors | Jun 5 – Jul 2 |
| Sweet corn | Sow outdoors | Jun 5 – May 30 |
| Watermelon & cantaloupe | Sow outdoors | Jun 19 – Jul 20 |
| Okra | Sow outdoors | Jun 12 – Jul 5 |
| Peas | Sow outdoors (spring) | Apr 19 – Jun 4 |
| Potatoes | Plant outdoors (spring) | Apr 19 – Jun 19 |
| Onions | Start seeds indoors (spring) | Mar 8 – Apr 4 |
| Onions | Transplant outdoors (spring) | May 6 – Jun 4 |
| Broccoli | Start seeds indoors (spring) | Apr 1 – May 5 |
| Broccoli | Transplant outdoors (spring) | May 6 – Jun 4 |
| Broccoli | Start seeds indoors (fall) | May 20 – May 30 |
| Broccoli | Transplant outdoors (fall) | Jun 19 – Jun 30 |
| Cabbage | Start seeds indoors (spring) | Mar 22 – Apr 19 |
| Cabbage | Transplant outdoors (spring) | Apr 19 – May 20 |
| Cabbage | Start seeds indoors (fall) | May 10 – Jun 9 |
| Cabbage | Transplant outdoors (fall) | Jun 9 – Jul 10 |
| Leaf lettuce | Sow outdoors (spring) | Apr 19 – Jul 5 |
| Leaf lettuce | Sow outdoors (fall) | Jun 9 – Jul 26 |
| Spinach | Sow outdoors (spring) | Apr 12 – May 26 |
| Spinach | Sow outdoors (fall) | Jun 26 – Jul 31 |
| Radishes | Sow outdoors (spring) | Apr 19 – Jun 9 |
| Radishes | Sow outdoors (fall) | Jun 9 – Aug 10 |
| Kale | Sow outdoors (spring) | May 6 – May 26 |
| Kale | Sow outdoors (fall) | Jun 2 – Jul 10 |
| Carrots | Sow outdoors (spring) | May 20 – Jul 5 |
| Carrots | Sow outdoors (fall) | May 10 – Jun 25 |
| Garlic | Plant outdoors (fall) | Sep 9 – Oct 10 |
Where these dates come from
ZIP code 58772 is matched to the NOAA station Northgate 5 Ese, ND, 27.6 km away, at 1,842 ft elevation (110 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Northgate 5 Ese, ND (used) | 1,842 ft | May 20 | Sep 19 |
| Powers Lake 1N, ND | 2,205 ft | May 18 | Sep 17 |
| Kenmare 1 Wsw, ND | 1,810 ft | May 15 | Sep 23 |
| Crosby, ND | 1,959 ft | May 17 | Sep 23 |
Frost dates near Portal
- Lignite, ND 58752 · last May 18, first Sep 17
- Flaxton, ND 58737 · last May 15, first Sep 23
- Columbus, ND 58727 · last May 17, first Sep 23
- Bowbells, ND 58721 · last May 15, first Sep 23
- Noonan, ND 58765 · last May 17, first Sep 23
- Powers Lake, ND 58773 · last May 18, first Sep 17
- Kenmare, ND 58746 · last May 15, first Sep 23
- Mcgregor, ND 58755 · last May 18, first Sep 17
Frequently asked questions
- When is the last frost in Portal, ND?
- For ZIP code 58772, the average last spring frost (32°F) is May 20, based on NOAA 1991-2020 climate normals for the Northgate 5 Ese, ND weather station. There is a 1-in-10 chance of a frost after June 2.
- When is the first frost in Portal, ND?
- The average first fall frost (32°F) is September 19. There is a 1-in-10 chance of frost by September 7, so tender plants are at risk from that point on.
- How long is the growing season in 58772?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 121 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.