Frost dates for 46077Zionsville, IN
The average last spring frost in Zionsville is April 21 and the average first fall frost is October 20, giving a typical growing season of about 180 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 21
- Average first fall frost
- Oct 20
- Growing season
- 180 days
Safer after May 6 (1-in-10 risk)
Possible by Oct 5 (1-in-10 risk)
Last frost typically in 175 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 18 · May 1 · May 17 | Sep 25 · Oct 8 · Oct 21 | 159 days | 100% |
| Frost / freeze (32°F) | Apr 6 · Apr 21 · May 6 | Oct 5 · Oct 20 · Nov 1 | 180 days | 100% |
| Hard freeze (28°F) | Mar 25 · Apr 9 · Apr 25 | Oct 16 · Oct 31 · Nov 13 | 204 days | 100% |
Planting calendar for Zionsville
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 21 – May 27 |
| Tomatoes | Transplant outdoors | May 7 – Jun 30 |
| Peppers | Start seeds indoors | Mar 21 – Apr 21 |
| Peppers | Transplant outdoors | May 21 – Jun 21 |
| Eggplant | Start seeds indoors | Apr 7 – May 6 |
| Eggplant | Transplant outdoors | May 21 – Jun 21 |
| Cucumbers | Sow outdoors | May 21 – Jul 10 |
| Summer squash | Sow outdoors | May 7 – Jun 21 |
| Winter squash & pumpkins | Sow outdoors | May 21 – Jun 21 |
| Snap beans | Sow outdoors | May 7 – Aug 2 |
| Sweet corn | Sow outdoors | May 7 – Jun 30 |
| Watermelon & cantaloupe | Sow outdoors | May 21 – Jun 21 |
| Okra | Sow outdoors | May 14 – Jun 6 |
| Peas | Sow outdoors (spring) | Mar 21 – May 6 |
| Potatoes | Plant outdoors (spring) | Mar 21 – May 21 |
| Onions | Start seeds indoors (spring) | Feb 7 – Mar 6 |
| Onions | Transplant outdoors (spring) | Apr 7 – May 6 |
| Broccoli | Start seeds indoors (spring) | Mar 3 – Apr 6 |
| Broccoli | Transplant outdoors (spring) | Apr 7 – May 6 |
| Broccoli | Start seeds indoors (fall) | Jun 20 – Jun 30 |
| Broccoli | Transplant outdoors (fall) | Jul 20 – Jul 31 |
| Cabbage | Start seeds indoors (spring) | Feb 21 – Mar 21 |
| Cabbage | Transplant outdoors (spring) | Mar 21 – Apr 21 |
| Cabbage | Start seeds indoors (fall) | Jun 10 – Jul 10 |
| Cabbage | Transplant outdoors (fall) | Jul 10 – Aug 10 |
| Leaf lettuce | Sow outdoors (spring) | Mar 21 – Jun 6 |
| Leaf lettuce | Sow outdoors (fall) | Jul 10 – Aug 26 |
| Spinach | Sow outdoors (spring) | Mar 14 – Apr 27 |
| Spinach | Sow outdoors (fall) | Jul 27 – Aug 31 |
| Radishes | Sow outdoors (spring) | Mar 21 – May 11 |
| Radishes | Sow outdoors (fall) | Jul 10 – Sep 10 |
| Kale | Sow outdoors (spring) | Apr 7 – Apr 27 |
| Kale | Sow outdoors (fall) | Jul 3 – Aug 10 |
| Carrots | Sow outdoors (spring) | Apr 21 – Jun 6 |
| Carrots | Sow outdoors (fall) | Jun 10 – Jul 26 |
| Garlic | Plant outdoors (fall) | Oct 10 – Nov 10 |
Where these dates come from
ZIP code 46077 is matched to the NOAA station Whitestown, IN, 8 km away, at 941 ft elevation (58 ft higher than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Whitestown, IN (used) | 941 ft | Apr 21 | Oct 20 |
| Indianapolis Eagle Creek Ap, IN | 823 ft | Apr 12 | Oct 29 |
| Carmel 3 E, IN | 752 ft | Apr 21 | Oct 21 |
| Castleton 2 S, IN | 824 ft | Apr 18 | Oct 26 |
Frost dates near Zionsville
- Whitestown, IN 46075 · last Apr 21, first Oct 20
- Indianapolis, IN 46278 · last Apr 12, first Oct 29
- Carmel, IN 46032 · last Apr 21, first Oct 21
- Westfield, IN 46074 · last Apr 21, first Oct 21
- Brownsburg, IN 46112 · last Apr 12, first Oct 29
- Lebanon, IN 46052 · last Apr 21, first Oct 20
- Pittsboro, IN 46167 · last Apr 23, first Oct 19
- Sheridan, IN 46069 · last Apr 23, first Oct 17
Frequently asked questions
- When is the last frost in Zionsville, IN?
- For ZIP code 46077, the average last spring frost (32°F) is April 21, based on NOAA 1991-2020 climate normals for the Whitestown, IN weather station. There is a 1-in-10 chance of a frost after May 6.
- When is the first frost in Zionsville, IN?
- The average first fall frost (32°F) is October 20. There is a 1-in-10 chance of frost by October 5, so tender plants are at risk from that point on.
- How long is the growing season in 46077?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 180 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.