Frost dates for 52540Brighton, IA
The average last spring frost in Brighton is April 28 and the average first fall frost is October 11, giving a typical growing season of about 165 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 28
- Average first fall frost
- Oct 11
- Growing season
- 165 days
Safer after May 11 (1-in-10 risk)
Possible by Sep 25 (1-in-10 risk)
Last frost typically in 178 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 19 | Sep 17 · Oct 1 · Oct 13 | 147 days | 100% |
| Frost / freeze (32°F) | Apr 13 · Apr 28 · May 11 | Sep 25 · Oct 11 · Oct 24 | 165 days | 100% |
| Hard freeze (28°F) | Apr 3 · Apr 17 · May 2 | Oct 7 · Oct 22 · Nov 1 | 187 days | 100% |
Planting calendar for Brighton
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 21 |
| 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 – Jul 1 |
| Summer squash | Sow outdoors | May 14 – Jun 28 |
| Winter squash & pumpkins | Sow outdoors | May 28 – Jun 28 |
| Snap beans | Sow outdoors | May 14 – Jul 24 |
| Sweet corn | Sow outdoors | May 14 – Jun 21 |
| 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 11 – Jun 21 |
| Broccoli | Transplant outdoors (fall) | Jul 11 – Jul 22 |
| Cabbage | Start seeds indoors (spring) | Feb 28 – Mar 28 |
| Cabbage | Transplant outdoors (spring) | Mar 28 – Apr 28 |
| Cabbage | Start seeds indoors (fall) | Jun 1 – Jul 1 |
| Cabbage | Transplant outdoors (fall) | Jul 1 – Aug 1 |
| Leaf lettuce | Sow outdoors (spring) | Mar 28 – Jun 13 |
| Leaf lettuce | Sow outdoors (fall) | Jul 1 – Aug 17 |
| Spinach | Sow outdoors (spring) | Mar 21 – May 4 |
| Spinach | Sow outdoors (fall) | Jul 18 – Aug 22 |
| Radishes | Sow outdoors (spring) | Mar 28 – May 18 |
| Radishes | Sow outdoors (fall) | Jul 1 – Sep 1 |
| Kale | Sow outdoors (spring) | Apr 14 – May 4 |
| Kale | Sow outdoors (fall) | Jun 24 – Aug 1 |
| Carrots | Sow outdoors (spring) | Apr 28 – Jun 13 |
| Carrots | Sow outdoors (fall) | Jun 1 – Jul 17 |
| Garlic | Plant outdoors (fall) | Oct 1 – Nov 1 |
Where these dates come from
ZIP code 52540 is matched to the NOAA station Washington, IA, 17.5 km away, at 687 ft elevation (9 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Washington, IA (used) | 687 ft | Apr 28 | Oct 11 |
| Fairfield, IA | 740 ft | Apr 27 | Oct 12 |
| Mt Pleasant 1 Ssw, IA | 730 ft | Apr 30 | Oct 10 |
| Sigourney, IA | 732 ft | Apr 24 | Oct 15 |
Frost dates near Brighton
- Richland, IA 52585 · last Apr 27, first Oct 12
- Wayland, IA 52654 · last Apr 28, first Oct 11
- Lockridge, IA 52635 · last Apr 27, first Oct 12
- Fairfield, IA 52557 · last Apr 27, first Oct 12
- Washington, IA 52353 · last Apr 28, first Oct 11
- Packwood, IA 52580 · last Apr 27, first Oct 12
- Rome, IA 52642 · last Apr 30, first Oct 10
- West Chester, IA 52359 · last Apr 28, first Oct 11
Frequently asked questions
- When is the last frost in Brighton, IA?
- For ZIP code 52540, the average last spring frost (32°F) is April 28, based on NOAA 1991-2020 climate normals for the Washington, IA weather station. There is a 1-in-10 chance of a frost after May 11.
- When is the first frost in Brighton, IA?
- The average first fall frost (32°F) is October 11. There is a 1-in-10 chance of frost by September 25, so tender plants are at risk from that point on.
- How long is the growing season in 52540?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 165 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.