Frost dates for 50835Benton, IA
The average last spring frost in Benton is April 25 and the average first fall frost is October 12, giving a typical growing season of about 169 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 25
- Average first fall frost
- Oct 12
- Growing season
- 169 days
Safer after May 9 (1-in-10 risk)
Possible by Sep 27 (1-in-10 risk)
Last frost typically in 180 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 21 · May 4 · May 20 | Sep 18 · Oct 1 · Oct 14 | 150 days | 100% |
| Frost / freeze (32°F) | Apr 10 · Apr 25 · May 9 | Sep 27 · Oct 12 · Oct 25 | 169 days | 100% |
| Hard freeze (28°F) | Apr 1 · Apr 14 · Apr 29 | Oct 9 · Oct 23 · Nov 3 | 191 days | 100% |
Planting calendar for Benton
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 25 – May 31 |
| Tomatoes | Transplant outdoors | May 11 – Jun 22 |
| Peppers | Start seeds indoors | Mar 25 – Apr 25 |
| Peppers | Transplant outdoors | May 25 – Jun 25 |
| Eggplant | Start seeds indoors | Apr 11 – May 10 |
| Eggplant | Transplant outdoors | May 25 – Jun 25 |
| Cucumbers | Sow outdoors | May 25 – Jul 2 |
| Summer squash | Sow outdoors | May 11 – Jun 25 |
| Winter squash & pumpkins | Sow outdoors | May 25 – Jun 25 |
| Snap beans | Sow outdoors | May 11 – Jul 25 |
| Sweet corn | Sow outdoors | May 11 – Jun 22 |
| Watermelon & cantaloupe | Sow outdoors | May 25 – Jun 25 |
| Okra | Sow outdoors | May 18 – Jun 10 |
| Peas | Sow outdoors (spring) | Mar 25 – May 10 |
| Potatoes | Plant outdoors (spring) | Mar 25 – May 25 |
| Onions | Start seeds indoors (spring) | Feb 11 – Mar 10 |
| Onions | Transplant outdoors (spring) | Apr 11 – May 10 |
| Broccoli | Start seeds indoors (spring) | Mar 7 – Apr 10 |
| Broccoli | Transplant outdoors (spring) | Apr 11 – May 10 |
| Broccoli | Start seeds indoors (fall) | Jun 12 – Jun 22 |
| Broccoli | Transplant outdoors (fall) | Jul 12 – Jul 23 |
| Cabbage | Start seeds indoors (spring) | Feb 25 – Mar 25 |
| Cabbage | Transplant outdoors (spring) | Mar 25 – Apr 25 |
| Cabbage | Start seeds indoors (fall) | Jun 2 – Jul 2 |
| Cabbage | Transplant outdoors (fall) | Jul 2 – Aug 2 |
| Leaf lettuce | Sow outdoors (spring) | Mar 25 – Jun 10 |
| Leaf lettuce | Sow outdoors (fall) | Jul 2 – Aug 18 |
| Spinach | Sow outdoors (spring) | Mar 18 – May 1 |
| Spinach | Sow outdoors (fall) | Jul 19 – Aug 23 |
| Radishes | Sow outdoors (spring) | Mar 25 – May 15 |
| Radishes | Sow outdoors (fall) | Jul 2 – Sep 2 |
| Kale | Sow outdoors (spring) | Apr 11 – May 1 |
| Kale | Sow outdoors (fall) | Jun 25 – Aug 2 |
| Carrots | Sow outdoors (spring) | Apr 25 – Jun 10 |
| Carrots | Sow outdoors (fall) | Jun 2 – Jul 18 |
| Garlic | Plant outdoors (fall) | Oct 2 – Nov 2 |
Where these dates come from
ZIP code 50835 is matched to the NOAA station Mt Ayr, IA, 10.6 km away, at 1,140 ft elevation (34 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Mt Ayr, IA (used) | 1,140 ft | Apr 25 | Oct 12 |
| Grant City, MO | 1,130 ft | Apr 24 | Oct 14 |
| Beaconsfield, IA | 1,215 ft | Apr 23 | Oct 17 |
| Grant City 5Wsw, MO | 1,089 ft | Apr 20 | Oct 19 |
Frost dates near Benton
- Redding, IA 50860 · last Apr 25, first Oct 12
- Mount Ayr, IA 50854 · last Apr 25, first Oct 12
- Diagonal, IA 50845 · last Apr 25, first Oct 12
- Clearfield, IA 50840 · last Apr 24, first Oct 15
- Blockton, IA 50836 · last Apr 24, first Oct 15
- Tingley, IA 50863 · last Apr 23, first Oct 17
- Shannon City, IA 50861 · last Apr 23, first Oct 17
- Grant City, MO 64456 · last Apr 24, first Oct 14
Frequently asked questions
- When is the last frost in Benton, IA?
- For ZIP code 50835, the average last spring frost (32°F) is April 25, based on NOAA 1991-2020 climate normals for the Mt Ayr, IA weather station. There is a 1-in-10 chance of a frost after May 9.
- When is the first frost in Benton, IA?
- The average first fall frost (32°F) is October 12. There is a 1-in-10 chance of frost by September 27, so tender plants are at risk from that point on.
- How long is the growing season in 50835?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 169 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.