Frost dates for 50518Barnum, IA
The average last spring frost in Barnum is April 28 and the average first fall frost is October 8, giving a typical growing season of about 162 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 28
- Average first fall frost
- Oct 8
- Growing season
- 162 days
Safer after May 9 (1-in-10 risk)
Possible by Sep 24 (1-in-10 risk)
Last frost typically in 183 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) | Apr 24 · May 6 · May 17 | Sep 17 · Sep 30 · Oct 12 | 144 days | 100% |
| Frost / freeze (32°F) | Apr 13 · Apr 28 · May 9 | Sep 24 · Oct 8 · Oct 22 | 162 days | 100% |
| Hard freeze (28°F) | Apr 4 · Apr 17 · May 1 | Oct 3 · Oct 19 · Nov 1 | 183 days | 100% |
Planting calendar for Barnum
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 | Mar 28 – Jun 3 |
| Tomatoes | Transplant outdoors | May 14 – Jun 18 |
| Peppers | Start seeds indoors | Mar 28 – Apr 28 |
| Peppers | Transplant outdoors | May 28 – Jun 28 |
| Eggplant | Start seeds indoors | Apr 14 – May 13 |
| Eggplant | Transplant outdoors | May 28 – Jun 28 |
| Cucumbers | Sow outdoors | May 28 – Jun 28 |
| Summer squash | Sow outdoors | May 14 – Jun 28 |
| Winter squash & pumpkins | Sow outdoors | May 28 – Jun 28 |
| Snap beans | Sow outdoors | May 14 – Jul 21 |
| Sweet corn | Sow outdoors | May 14 – Jun 18 |
| Watermelon & cantaloupe | Sow outdoors | May 28 – Jun 28 |
| Okra | Sow outdoors | May 21 – Jun 13 |
| Peas | Sow outdoors (spring) | Mar 28 – May 13 |
| Potatoes | Plant outdoors (spring) | Mar 28 – May 28 |
| Onions | Start seeds indoors (spring) | Feb 14 – Mar 13 |
| Onions | Transplant outdoors (spring) | Apr 14 – May 13 |
| Broccoli | Start seeds indoors (spring) | Mar 10 – Apr 13 |
| Broccoli | Transplant outdoors (spring) | Apr 14 – May 13 |
| Broccoli | Start seeds indoors (fall) | Jun 8 – Jun 18 |
| Broccoli | Transplant outdoors (fall) | Jul 8 – Jul 19 |
| Cabbage | Start seeds indoors (spring) | Feb 28 – Mar 28 |
| Cabbage | Transplant outdoors (spring) | Mar 28 – Apr 28 |
| Cabbage | Start seeds indoors (fall) | May 29 – Jun 28 |
| Cabbage | Transplant outdoors (fall) | Jun 28 – Jul 29 |
| Leaf lettuce | Sow outdoors (spring) | Mar 28 – Jun 13 |
| Leaf lettuce | Sow outdoors (fall) | Jun 28 – Aug 14 |
| Spinach | Sow outdoors (spring) | Mar 21 – May 4 |
| Spinach | Sow outdoors (fall) | Jul 15 – Aug 19 |
| Radishes | Sow outdoors (spring) | Mar 28 – May 18 |
| Radishes | Sow outdoors (fall) | Jun 28 – Aug 29 |
| Kale | Sow outdoors (spring) | Apr 14 – May 4 |
| Kale | Sow outdoors (fall) | Jun 21 – Jul 29 |
| Carrots | Sow outdoors (spring) | Apr 28 – Jun 13 |
| Carrots | Sow outdoors (fall) | May 29 – Jul 14 |
| Garlic | Plant outdoors (fall) | Sep 28 – Oct 29 |
Where these dates come from
ZIP code 50518 is matched to the NOAA station Ft Dodge 5Nnw, IA, 15.8 km away, at 1,115 ft elevation (30 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Ft Dodge 5Nnw, IA (used) | 1,115 ft | Apr 28 | Oct 8 |
| Rockwell City, IA | 1,214 ft | Apr 26 | Oct 10 |
| Humboldt Wtp, IA | 1,100 ft | Apr 27 | Oct 9 |
| Dakota City, IA | 1,110 ft | Apr 26 | Oct 12 |
Frost dates near Barnum
- Knierim, IA 50552 · last Apr 26, first Oct 10
- Moorland, IA 50566 · last Apr 28, first Oct 8
- Clare, IA 50524 · last Apr 28, first Oct 8
- Manson, IA 50563 · last Apr 26, first Oct 10
- Fort Dodge, IA 50501 · last Apr 28, first Oct 8
- Somers, IA 50586 · last Apr 26, first Oct 10
- Callender, IA 50523 · last Apr 28, first Oct 8
- Palmer, IA 50571 · last Apr 26, first Oct 7
Frequently asked questions
- When is the last frost in Barnum, IA?
- For ZIP code 50518, the average last spring frost (32°F) is April 28, based on NOAA 1991-2020 climate normals for the Ft Dodge 5Nnw, IA weather station. There is a 1-in-10 chance of a frost after May 9.
- When is the first frost in Barnum, IA?
- The average first fall frost (32°F) is October 8. There is a 1-in-10 chance of frost by September 24, so tender plants are at risk from that point on.
- How long is the growing season in 50518?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 162 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.