Frost dates for 58565Riverdale, ND
The average last spring frost in Riverdale is May 12 and the average first fall frost is October 3, giving a typical growing season of about 143 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 12
- Average first fall frost
- Oct 3
- Growing season
- 143 days
Safer after May 27 (1-in-10 risk)
Possible by Sep 20 (1-in-10 risk)
Last frost typically in 190 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 10 · May 22 · Jun 4 | Sep 12 · Sep 25 · Oct 5 | 126 days | 100% |
| Frost / freeze (32°F) | Apr 30 · May 12 · May 27 | Sep 20 · Oct 3 · Oct 14 | 143 days | 100% |
| Hard freeze (28°F) | Apr 16 · May 1 · May 19 | Sep 28 · Oct 12 · Oct 24 | 163 days | 100% |
Planting calendar for Riverdale
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 13 |
| 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 23 |
| Summer squash | Sow outdoors | May 28 – Jul 12 |
| Winter squash & pumpkins | Sow outdoors | Jun 11 – Jul 12 |
| Snap beans | Sow outdoors | May 28 – Jul 16 |
| Sweet corn | Sow outdoors | May 28 – Jun 13 |
| 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 3 – Jun 13 |
| Broccoli | Transplant outdoors (fall) | Jul 3 – Jul 14 |
| Cabbage | Start seeds indoors (spring) | Mar 14 – Apr 11 |
| Cabbage | Transplant outdoors (spring) | Apr 11 – May 12 |
| Cabbage | Start seeds indoors (fall) | May 24 – Jun 23 |
| Cabbage | Transplant outdoors (fall) | Jun 23 – Jul 24 |
| Leaf lettuce | Sow outdoors (spring) | Apr 11 – Jun 27 |
| Leaf lettuce | Sow outdoors (fall) | Jun 23 – Aug 9 |
| Spinach | Sow outdoors (spring) | Apr 4 – May 18 |
| Spinach | Sow outdoors (fall) | Jul 10 – Aug 14 |
| Radishes | Sow outdoors (spring) | Apr 11 – Jun 1 |
| Radishes | Sow outdoors (fall) | Jun 23 – Aug 24 |
| Kale | Sow outdoors (spring) | Apr 28 – May 18 |
| Kale | Sow outdoors (fall) | Jun 16 – Jul 24 |
| Carrots | Sow outdoors (spring) | May 12 – Jun 27 |
| Carrots | Sow outdoors (fall) | May 24 – Jul 9 |
| Garlic | Plant outdoors (fall) | Sep 23 – Oct 24 |
Where these dates come from
ZIP code 58565 is matched to the NOAA station Riverdale, ND, 0.8 km away, at 1,962 ft elevation (7 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Riverdale, ND (used) | 1,962 ft | May 12 | Oct 3 |
| Garrison, ND | 1,910 ft | May 14 | Sep 26 |
| Underwood, ND | 2,045 ft | May 10 | Sep 29 |
| Garrison, ND | 1,932 ft | May 12 | Sep 30 |
Frost dates near Riverdale
- Coleharbor, ND 58531 · last May 10, first Sep 29
- Underwood, ND 58576 · last May 10, first Sep 29
- Stanton, ND 58571 · last May 12, first Sep 30
- Hazen, ND 58545 · last May 21, first Sep 20
- Garrison, ND 58540 · last May 14, first Sep 26
- Washburn, ND 58577 · last May 12, first Sep 30
- Max, ND 58759 · last May 10, first Sep 28
- Turtle Lake, ND 58575 · last May 14, first Sep 26
Frequently asked questions
- When is the last frost in Riverdale, ND?
- For ZIP code 58565, the average last spring frost (32°F) is May 12, based on NOAA 1991-2020 climate normals for the Riverdale, ND weather station. There is a 1-in-10 chance of a frost after May 27.
- When is the first frost in Riverdale, ND?
- The average first fall frost (32°F) is October 3. There is a 1-in-10 chance of frost by September 20, so tender plants are at risk from that point on.
- How long is the growing season in 58565?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 143 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.