Frost dates for 46231Indianapolis, IN
The average last spring frost in Indianapolis is April 15 and the average first fall frost is October 26, giving a typical growing season of about 193 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 15
- Average first fall frost
- Oct 26
- Growing season
- 193 days
Safer after May 2 (1-in-10 risk)
Possible by Oct 13 (1-in-10 risk)
Last frost typically in 169 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 11 · Apr 26 · May 12 | Oct 5 · Oct 17 · Oct 28 | 171 days | 100% |
| Frost / freeze (32°F) | Apr 2 · Apr 15 · May 2 | Oct 13 · Oct 26 · Nov 7 | 193 days | 100% |
| Hard freeze (28°F) | Mar 18 · Apr 4 · Apr 21 | Oct 24 · Nov 5 · Nov 21 | 215 days | 100% |
Planting calendar for Indianapolis
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 15 – May 21 |
| Tomatoes | Transplant outdoors | May 1 – Jul 6 |
| Peppers | Start seeds indoors | Mar 15 – Apr 15 |
| Peppers | Transplant outdoors | May 15 – Jun 15 |
| Eggplant | Start seeds indoors | Apr 1 – Apr 30 |
| Eggplant | Transplant outdoors | May 15 – Jun 15 |
| Cucumbers | Sow outdoors | May 15 – Jul 16 |
| Summer squash | Sow outdoors | May 1 – Jun 15 |
| Winter squash & pumpkins | Sow outdoors | May 15 – Jun 15 |
| Snap beans | Sow outdoors | May 1 – Aug 8 |
| Sweet corn | Sow outdoors | May 1 – Jul 6 |
| Watermelon & cantaloupe | Sow outdoors | May 15 – Jun 15 |
| Okra | Sow outdoors | May 8 – May 31 |
| Peas | Sow outdoors (spring) | Mar 15 – Apr 30 |
| Potatoes | Plant outdoors (spring) | Mar 15 – May 15 |
| Onions | Start seeds indoors (spring) | Feb 1 – Feb 28 |
| Onions | Transplant outdoors (spring) | Apr 1 – Apr 30 |
| Broccoli | Start seeds indoors (spring) | Feb 25 – Mar 31 |
| Broccoli | Transplant outdoors (spring) | Apr 1 – Apr 30 |
| Broccoli | Start seeds indoors (fall) | Jun 26 – Jul 6 |
| Broccoli | Transplant outdoors (fall) | Jul 26 – Aug 6 |
| Cabbage | Start seeds indoors (spring) | Feb 15 – Mar 15 |
| Cabbage | Transplant outdoors (spring) | Mar 15 – Apr 15 |
| Cabbage | Start seeds indoors (fall) | Jun 16 – Jul 16 |
| Cabbage | Transplant outdoors (fall) | Jul 16 – Aug 16 |
| Leaf lettuce | Sow outdoors (spring) | Mar 15 – May 31 |
| Leaf lettuce | Sow outdoors (fall) | Jul 16 – Sep 1 |
| Spinach | Sow outdoors (spring) | Mar 8 – Apr 21 |
| Spinach | Sow outdoors (fall) | Aug 2 – Sep 6 |
| Radishes | Sow outdoors (spring) | Mar 15 – May 5 |
| Radishes | Sow outdoors (fall) | Jul 16 – Sep 16 |
| Kale | Sow outdoors (spring) | Apr 1 – Apr 21 |
| Kale | Sow outdoors (fall) | Jul 9 – Aug 16 |
| Carrots | Sow outdoors (spring) | Apr 15 – May 31 |
| Carrots | Sow outdoors (fall) | Jun 16 – Aug 1 |
| Garlic | Plant outdoors (fall) | Oct 16 – Nov 16 |
Where these dates come from
ZIP code 46231 is matched to the NOAA station Indianapolis, IN, 2 km away, at 790 ft elevation (3 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Indianapolis, IN (used) | 790 ft | Apr 15 | Oct 26 |
| Indianapolis Nwfo, IN | 790 ft | Apr 12 | Oct 27 |
| Indianapolis Eagle Creek Ap, IN | 823 ft | Apr 12 | Oct 29 |
| Indianapolis Se Side, IN | 845 ft | Apr 20 | Oct 21 |
Frost dates near Indianapolis
- Indianapolis, IN 46241 · last Apr 15, first Oct 26
- West Newton, IN 46183 · last Apr 15, first Oct 26
- Camby, IN 46113 · last Apr 15, first Oct 26
- Plainfield, IN 46168 · last Apr 15, first Oct 26
- Avon, IN 46123 · last Apr 12, first Oct 29
- Mooresville, IN 46158 · last Apr 15, first Oct 26
- Greenwood, IN 46142 · last Apr 15, first Oct 26
- Clayton, IN 46118 · last Apr 15, first Oct 26
Frequently asked questions
- When is the last frost in Indianapolis, IN?
- For ZIP code 46231, the average last spring frost (32°F) is April 15, based on NOAA 1991-2020 climate normals for the Indianapolis, IN weather station. There is a 1-in-10 chance of a frost after May 2.
- When is the first frost in Indianapolis, IN?
- The average first fall frost (32°F) is October 26. There is a 1-in-10 chance of frost by October 13, so tender plants are at risk from that point on.
- How long is the growing season in 46231?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 193 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.