Frost dates for 58369Saint John, ND
The average last spring frost in Saint John is May 19 and the average first fall frost is September 24, giving a typical growing season of about 126 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 19
- Average first fall frost
- Sep 24
- Growing season
- 126 days
Safer after Jun 1 (1-in-10 risk)
Possible by Sep 10 (1-in-10 risk)
Last frost typically in 198 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 16 · May 30 · Jun 21 | Sep 1 · Sep 14 · Sep 27 | 104 days | 100% |
| Frost / freeze (32°F) | May 5 · May 19 · Jun 1 | Sep 10 · Sep 24 · Oct 5 | 126 days | 100% |
| Hard freeze (28°F) | Apr 28 · May 9 · May 24 | Sep 18 · Oct 2 · Oct 16 | 143 days | 100% |
Planting calendar for Saint John
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 18 – Jun 24 |
| Tomatoes | Transplant outdoors | Jun 4 – Jun 4 |
| Peppers | Start seeds indoors | Apr 18 – May 19 |
| Peppers | Transplant outdoors | Jun 18 – Jul 19 |
| Eggplant | Start seeds indoors | May 5 – Jun 3 |
| Eggplant | Transplant outdoors | Jun 18 – Jul 19 |
| Cucumbers | Sow outdoors | Jun 18 – Jun 14 |
| Summer squash | Sow outdoors | Jun 4 – Jul 19 |
| Winter squash & pumpkins | Sow outdoors | Jun 18 – Jul 19 |
| Snap beans | Sow outdoors | Jun 4 – Jul 7 |
| Sweet corn | Sow outdoors | Jun 4 – Jun 4 |
| Watermelon & cantaloupe | Sow outdoors | Jun 18 – Jul 19 |
| Okra | Sow outdoors | Jun 11 – Jul 4 |
| Peas | Sow outdoors (spring) | Apr 18 – Jun 3 |
| Potatoes | Plant outdoors (spring) | Apr 18 – Jun 18 |
| Onions | Start seeds indoors (spring) | Mar 7 – Apr 3 |
| Onions | Transplant outdoors (spring) | May 5 – Jun 3 |
| Broccoli | Start seeds indoors (spring) | Mar 31 – May 4 |
| Broccoli | Transplant outdoors (spring) | May 5 – Jun 3 |
| Broccoli | Start seeds indoors (fall) | May 25 – Jun 4 |
| Broccoli | Transplant outdoors (fall) | Jun 24 – Jul 5 |
| Cabbage | Start seeds indoors (spring) | Mar 21 – Apr 18 |
| Cabbage | Transplant outdoors (spring) | Apr 18 – May 19 |
| Cabbage | Start seeds indoors (fall) | May 15 – Jun 14 |
| Cabbage | Transplant outdoors (fall) | Jun 14 – Jul 15 |
| Leaf lettuce | Sow outdoors (spring) | Apr 18 – Jul 4 |
| Leaf lettuce | Sow outdoors (fall) | Jun 14 – Jul 31 |
| Spinach | Sow outdoors (spring) | Apr 11 – May 25 |
| Spinach | Sow outdoors (fall) | Jul 1 – Aug 5 |
| Radishes | Sow outdoors (spring) | Apr 18 – Jun 8 |
| Radishes | Sow outdoors (fall) | Jun 14 – Aug 15 |
| Kale | Sow outdoors (spring) | May 5 – May 25 |
| Kale | Sow outdoors (fall) | Jun 7 – Jul 15 |
| Carrots | Sow outdoors (spring) | May 19 – Jul 4 |
| Carrots | Sow outdoors (fall) | May 15 – Jun 30 |
| Garlic | Plant outdoors (fall) | Sep 14 – Oct 15 |
Where these dates come from
ZIP code 58369 is matched to the NOAA station Belcourt Keya Radio, ND, 10.7 km away, at 1,960 ft elevation (123 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Belcourt Keya Radio, ND (used) | 1,960 ft | May 19 | Sep 24 |
| Rolla 1Ne, ND | 1,833 ft | May 20 | Sep 26 |
| Hansboro 4 Nne, ND | 1,540 ft | May 18 | Sep 23 |
| Rolette 3Se, ND | 1,620 ft | May 22 | Sep 20 |
Frost dates near Saint John
- Belcourt, ND 58316 · last May 19, first Sep 24
- Rolla, ND 58367 · last May 20, first Sep 26
- Dunseith, ND 58329 · last May 19, first Sep 24
- Hansboro, ND 58339 · last May 20, first Sep 26
- Rolette, ND 58366 · last May 22, first Sep 20
- Perth, ND 58363 · last May 20, first Sep 26
- Mylo, ND 58353 · last May 22, first Sep 20
- Agate, ND 58310 · last May 22, first Sep 20
Frequently asked questions
- When is the last frost in Saint John, ND?
- For ZIP code 58369, the average last spring frost (32°F) is May 19, based on NOAA 1991-2020 climate normals for the Belcourt Keya Radio, ND weather station. There is a 1-in-10 chance of a frost after June 1.
- When is the first frost in Saint John, ND?
- The average first fall frost (32°F) is September 24. There is a 1-in-10 chance of frost by September 10, so tender plants are at risk from that point on.
- How long is the growing season in 58369?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 126 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.