When to plant in New Castle, IN
USDA Zone 6aEverything below — frost dates, hardiness zone, and what to plant when in New Castle, Indiana — is derived from the closest NOAA station with complete climate normals.
Zone 6a means New Castle sees real winter cold, but a good range of perennials survive; the frost dates above govern when annual vegetables go out.
The average last spring frost in New Castle is now 5 days later than in the 1981–2010 normals. See how frost dates are shifting nationwide →
Frost probability
NEW CASTLE 3 SW · 1991–2020The date the last spring and first fall frost occur, by threshold and probability. A 90% date is later in spring — and earlier in fall — than a 10% date; the 50% · 32°F row is what most gardeners plan around. These are New Castle’s own odds, recorded at NEW CASTLE 3 SW.
| Threshold | SPRING 10% | SPRING 50% | SPRING 90% | FALL 10% | FALL 50% | FALL 90% |
|---|---|---|---|---|---|---|
| 36°F | May 21 | May 6 | Apr 21 | Sep 24 | Oct 7 | Oct 18 |
| 32°F | May 12 | Apr 27 | Apr 11 | Oct 4 | Oct 17 | Oct 28 |
| 28°F | May 3 | Apr 15 | Mar 31 | Oct 13 | Oct 27 | Nov 8 |
Download this table as CSV ↓ — every threshold and probability, plus this city’s planting-window dates.
What to plant now
TODAY · JULY 19Full-year planting calendar
Each bar is the exact window to take a planting action in New Castle, drawn to the day from the local frost dates. The dashed line is today.
Nearby weather stations
3 within 35 km · complete 32°F normalsWhen stations disagree by more than a few days, that spread is real microclimate variation — elevation, water, urban heat. Judge which station best matches your own yard.
New Castle planting FAQ
When is the last spring frost in New Castle, IN?
New Castle's average last spring frost falls near April 27 — the 50% mark at 32°F in the 1991–2020 normals. Hold tender transplants until the risk has passed, then plant out.
When is the first fall frost in New Castle, IN?
In New Castle, the first 32°F freeze of fall lands around October 17 on average. Time your last harvests and any season-extension cover before it.
What hardiness zone is New Castle in?
New Castle is in USDA hardiness zone 6a. In zone 6a, winters are moderate — most common vegetables grow well in season.
How long is the growing season in New Castle?
There are roughly 173 frost-free days in New Castle (a moderate growing season), running from the average last frost around April 27 to the first fall frost near October 17.
When should I plant tomatoes in New Castle?
In New Castle, start tomato seeds indoors around March 2–March 16, then transplant seedlings outdoors around May 4 once the danger of frost has passed.
Never miss a window in New Castle
An email when it’s time to start seeds, transplant, and sow — timed to New Castle’s frost dates. Double opt-in, one-click unsubscribe, no spam.
Nearby cities
8 within reach- Muncie · 31 km
- Yorktown · 31 km
- Anderson · 33 km
- Connersville · 35 km
- Greenfield · 37 km
- Richmond · 42 km
- McCordsville · 47 km
- Fishers · 51 km
Frost dates recorded at NEW CASTLE 3 SW, 4 km from the city center · 1991–2020 NOAA climate normals · zone from the USDA/PRISM 2023 map. How we compute this.
BlissGarden. "When to Plant in New Castle, IN — Frost Dates & Zone 6a." Frost normals: NOAA NCEI U.S. Climate Normals 1991–2020, station USC00126164. Retrieved from https://blissgarden.com/indiana/new-castle.