Frost dates for 46259Indianapolis, IN
The average last spring frost in Indianapolis is April 20 and the average first fall frost is October 21, giving a typical growing season of about 183 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 20
- Average first fall frost
- Oct 21
- Growing season
- 183 days
Safer after May 5 (1-in-10 risk)
Possible by Oct 7 (1-in-10 risk)
Last frost typically in 176 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 16 · Apr 30 · May 17 | Sep 27 · Oct 11 · Oct 24 | 161 days | 100% |
| Frost / freeze (32°F) | Apr 6 · Apr 20 · May 5 | Oct 7 · Oct 21 · Nov 3 | 183 days | 100% |
| Hard freeze (28°F) | Mar 25 · Apr 7 · Apr 23 | Oct 20 · Nov 1 · Nov 15 | 205 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 20 – May 26 |
| Tomatoes | Transplant outdoors | May 6 – Jul 1 |
| Peppers | Start seeds indoors | Mar 20 – Apr 20 |
| Peppers | Transplant outdoors | May 20 – Jun 20 |
| Eggplant | Start seeds indoors | Apr 6 – May 5 |
| Eggplant | Transplant outdoors | May 20 – Jun 20 |
| Cucumbers | Sow outdoors | May 20 – Jul 11 |
| Summer squash | Sow outdoors | May 6 – Jun 20 |
| Winter squash & pumpkins | Sow outdoors | May 20 – Jun 20 |
| Snap beans | Sow outdoors | May 6 – Aug 3 |
| Sweet corn | Sow outdoors | May 6 – Jul 1 |
| Watermelon & cantaloupe | Sow outdoors | May 20 – Jun 20 |
| Okra | Sow outdoors | May 13 – Jun 5 |
| Peas | Sow outdoors (spring) | Mar 20 – May 5 |
| Potatoes | Plant outdoors (spring) | Mar 20 – May 20 |
| Onions | Start seeds indoors (spring) | Feb 6 – Mar 5 |
| Onions | Transplant outdoors (spring) | Apr 6 – May 5 |
| Broccoli | Start seeds indoors (spring) | Mar 2 – Apr 5 |
| Broccoli | Transplant outdoors (spring) | Apr 6 – May 5 |
| Broccoli | Start seeds indoors (fall) | Jun 21 – Jul 1 |
| Broccoli | Transplant outdoors (fall) | Jul 21 – Aug 1 |
| Cabbage | Start seeds indoors (spring) | Feb 20 – Mar 20 |
| Cabbage | Transplant outdoors (spring) | Mar 20 – Apr 20 |
| Cabbage | Start seeds indoors (fall) | Jun 11 – Jul 11 |
| Cabbage | Transplant outdoors (fall) | Jul 11 – Aug 11 |
| Leaf lettuce | Sow outdoors (spring) | Mar 20 – Jun 5 |
| Leaf lettuce | Sow outdoors (fall) | Jul 11 – Aug 27 |
| Spinach | Sow outdoors (spring) | Mar 13 – Apr 26 |
| Spinach | Sow outdoors (fall) | Jul 28 – Sep 1 |
| Radishes | Sow outdoors (spring) | Mar 20 – May 10 |
| Radishes | Sow outdoors (fall) | Jul 11 – Sep 11 |
| Kale | Sow outdoors (spring) | Apr 6 – Apr 26 |
| Kale | Sow outdoors (fall) | Jul 4 – Aug 11 |
| Carrots | Sow outdoors (spring) | Apr 20 – Jun 5 |
| Carrots | Sow outdoors (fall) | Jun 11 – Jul 27 |
| Garlic | Plant outdoors (fall) | Oct 11 – Nov 11 |
Where these dates come from
ZIP code 46259 is matched to the NOAA station Indianapolis Se Side, IN, 8.1 km away, at 845 ft elevation (31 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Indianapolis Se Side, IN (used) | 845 ft | Apr 20 | Oct 21 |
| Shelbyville Muni Ap, IN | 804 ft | Apr 14 | Oct 23 |
| Franklin Wwtp, IN | 720 ft | Apr 20 | Oct 19 |
| Shelbyville Sewage Plt, IN | 752 ft | Apr 17 | Oct 22 |
Frost dates near Indianapolis
- Indianapolis, IN 46239 · last Apr 20, first Oct 21
- Beech Grove, IN 46107 · last Apr 20, first Oct 21
- Fairland, IN 46126 · last Apr 14, first Oct 23
- New Palestine, IN 46163 · last Apr 20, first Oct 21
- Needham, IN 46162 · last Apr 17, first Oct 22
- Boggstown, IN 46110 · last Apr 17, first Oct 22
- Whiteland, IN 46184 · last Apr 20, first Oct 21
- Greenwood, IN 46142 · last Apr 15, first Oct 26
Frequently asked questions
- When is the last frost in Indianapolis, IN?
- For ZIP code 46259, the average last spring frost (32°F) is April 20, based on NOAA 1991-2020 climate normals for the Indianapolis Se Side, IN weather station. There is a 1-in-10 chance of a frost after May 5.
- When is the first frost in Indianapolis, IN?
- The average first fall frost (32°F) is October 21. There is a 1-in-10 chance of frost by October 7, so tender plants are at risk from that point on.
- How long is the growing season in 46259?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 183 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.