Frost dates for 59337Jordan, MT
The average last spring frost in Jordan is May 21 and the average first fall frost is September 18, giving a typical growing season of about 118 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 21
- Average first fall frost
- Sep 18
- Growing season
- 118 days
Safer after Jun 2 (1-in-10 risk)
Possible by Sep 4 (1-in-10 risk)
Last frost typically in 199 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 18 · May 30 · Jun 16 | Aug 26 · Sep 8 · Sep 21 | 99 days | 100% |
| Frost / freeze (32°F) | May 8 · May 21 · Jun 2 | Sep 4 · Sep 18 · Oct 1 | 118 days | 100% |
| Hard freeze (28°F) | Apr 26 · May 9 · May 23 | Sep 13 · Sep 26 · Oct 9 | 138 days | 100% |
Planting calendar for Jordan
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 20 – Jun 26 |
| Tomatoes | Transplant outdoors | Jun 6 – May 29 |
| Peppers | Start seeds indoors | Apr 20 – May 21 |
| Peppers | Transplant outdoors | Jun 20 – Jul 21 |
| Eggplant | Start seeds indoors | May 7 – Jun 5 |
| Eggplant | Transplant outdoors | Jun 20 – Jul 21 |
| Cucumbers | Sow outdoors | Jun 20 – Jun 8 |
| Summer squash | Sow outdoors | Jun 6 – Jul 21 |
| Winter squash & pumpkins | Sow outdoors | Jun 20 – Jul 21 |
| Snap beans | Sow outdoors | Jun 6 – Jul 1 |
| Sweet corn | Sow outdoors | Jun 6 – May 29 |
| Watermelon & cantaloupe | Sow outdoors | Jun 20 – Jul 21 |
| Okra | Sow outdoors | Jun 13 – Jul 6 |
| Peas | Sow outdoors (spring) | Apr 20 – Jun 5 |
| Potatoes | Plant outdoors (spring) | Apr 20 – Jun 20 |
| Onions | Start seeds indoors (spring) | Mar 9 – Apr 5 |
| Onions | Transplant outdoors (spring) | May 7 – Jun 5 |
| Broccoli | Start seeds indoors (spring) | Apr 2 – May 6 |
| Broccoli | Transplant outdoors (spring) | May 7 – Jun 5 |
| Broccoli | Start seeds indoors (fall) | May 19 – May 29 |
| Broccoli | Transplant outdoors (fall) | Jun 18 – Jun 29 |
| Cabbage | Start seeds indoors (spring) | Mar 23 – Apr 20 |
| Cabbage | Transplant outdoors (spring) | Apr 20 – May 21 |
| Cabbage | Start seeds indoors (fall) | May 9 – Jun 8 |
| Cabbage | Transplant outdoors (fall) | Jun 8 – Jul 9 |
| Leaf lettuce | Sow outdoors (spring) | Apr 20 – Jul 6 |
| Leaf lettuce | Sow outdoors (fall) | Jun 8 – Jul 25 |
| Spinach | Sow outdoors (spring) | Apr 13 – May 27 |
| Spinach | Sow outdoors (fall) | Jun 25 – Jul 30 |
| Radishes | Sow outdoors (spring) | Apr 20 – Jun 10 |
| Radishes | Sow outdoors (fall) | Jun 8 – Aug 9 |
| Kale | Sow outdoors (spring) | May 7 – May 27 |
| Kale | Sow outdoors (fall) | Jun 1 – Jul 9 |
| Carrots | Sow outdoors (spring) | May 21 – Jul 6 |
| Carrots | Sow outdoors (fall) | May 9 – Jun 24 |
| Garlic | Plant outdoors (fall) | Sep 8 – Oct 9 |
Where these dates come from
ZIP code 59337 is matched to the NOAA station Jordan, MT, 0.7 km away, at 2,620 ft elevation (22 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Jordan, MT (used) | 2,620 ft | May 21 | Sep 18 |
| Jordan Ap, MT | 2,662 ft | May 18 | Sep 20 |
| Cohagen, MT | 2,720 ft | May 25 | Sep 14 |
| Rock Springs, MT | 3,024 ft | May 15 | Sep 25 |
Frost dates near Jordan
- Brusett, MT 59318 · last May 18, first Sep 20
- Cohagen, MT 59322 · last May 25, first Sep 14
- Sand Springs, MT 59077 · last May 5, first Oct 4
- Mosby, MT 59058 · last May 5, first Oct 4
- Fort Peck, MT 59223 · last May 8, first Oct 1
- Angela, MT 59312 · last May 15, first Sep 25
- Brockway, MT 59214 · last May 20, first Sep 19
- Ingomar, MT 59039 · last May 21, first Sep 19
Frequently asked questions
- When is the last frost in Jordan, MT?
- For ZIP code 59337, the average last spring frost (32°F) is May 21, based on NOAA 1991-2020 climate normals for the Jordan, MT weather station. There is a 1-in-10 chance of a frost after June 2.
- When is the first frost in Jordan, MT?
- The average first fall frost (32°F) is September 18. There is a 1-in-10 chance of frost by September 4, so tender plants are at risk from that point on.
- How long is the growing season in 59337?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 118 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.