Frost dates for 17059Mifflintown, PA
The average last spring frost in Mifflintown is April 21 and the average first fall frost is October 24, giving a typical growing season of about 185 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- Apr 21
- Average first fall frost
- Oct 24
- Growing season
- 185 days
Safer after May 9 (1-in-10 risk)
Possible by Oct 7 (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 18 · May 2 · May 19 | Sep 29 · Oct 13 · Oct 27 | 161 days | 100% |
| Frost / freeze (32°F) | Apr 6 · Apr 21 · May 9 | Oct 7 · Oct 24 · Nov 7 | 185 days | 100% |
| Hard freeze (28°F) | Mar 24 · Apr 6 · Apr 21 | Oct 21 · Nov 5 · Nov 19 | 211 days | 100% |
Planting calendar for Mifflintown
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 – Jul 4 |
| 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 14 |
| Summer squash | Sow outdoors | May 7 – Jun 21 |
| Winter squash & pumpkins | Sow outdoors | May 21 – Jun 21 |
| Snap beans | Sow outdoors | May 7 – Aug 6 |
| Sweet corn | Sow outdoors | May 7 – Jul 4 |
| 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 24 – Jul 4 |
| Broccoli | Transplant outdoors (fall) | Jul 24 – Aug 4 |
| Cabbage | Start seeds indoors (spring) | Feb 21 – Mar 21 |
| Cabbage | Transplant outdoors (spring) | Mar 21 – Apr 21 |
| Cabbage | Start seeds indoors (fall) | Jun 14 – Jul 14 |
| Cabbage | Transplant outdoors (fall) | Jul 14 – Aug 14 |
| Leaf lettuce | Sow outdoors (spring) | Mar 21 – Jun 6 |
| Leaf lettuce | Sow outdoors (fall) | Jul 14 – Aug 30 |
| Spinach | Sow outdoors (spring) | Mar 14 – Apr 27 |
| Spinach | Sow outdoors (fall) | Jul 31 – Sep 4 |
| Radishes | Sow outdoors (spring) | Mar 21 – May 11 |
| Radishes | Sow outdoors (fall) | Jul 14 – Sep 14 |
| Kale | Sow outdoors (spring) | Apr 7 – Apr 27 |
| Kale | Sow outdoors (fall) | Jul 7 – Aug 14 |
| Carrots | Sow outdoors (spring) | Apr 21 – Jun 6 |
| Carrots | Sow outdoors (fall) | Jun 14 – Jul 30 |
| Garlic | Plant outdoors (fall) | Oct 14 – Nov 14 |
Where these dates come from
ZIP code 17059 is matched to the NOAA station Lewistown, PA, 16.4 km away, at 460 ft elevation (52 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Lewistown, PA (used) | 460 ft | Apr 21 | Oct 24 |
| Bloserville 1 N, PA | 700 ft | Apr 18 | Oct 26 |
| Millheim, PA | 1,120 ft | May 5 | Oct 6 |
| Laurelton Ctr, PA | 800 ft | Apr 25 | Oct 19 |
Frost dates near Mifflintown
- Mifflin, PA 17058 · last Apr 21, first Oct 24
- Mexico, PA 17056 · last Apr 21, first Oct 24
- Oakland Mills, PA 17076 · last Apr 21, first Oct 24
- Port Royal, PA 17082 · last Apr 21, first Oct 24
- Mc Alisterville, PA 17049 · last Apr 21, first Oct 24
- Mc Clure, PA 17841 · last Apr 21, first Oct 24
- Thompsontown, PA 17094 · last Apr 21, first Oct 24
- Ickesburg, PA 17037 · last Apr 21, first Oct 24
Frequently asked questions
- When is the last frost in Mifflintown, PA?
- For ZIP code 17059, the average last spring frost (32°F) is April 21, based on NOAA 1991-2020 climate normals for the Lewistown, PA weather station. There is a 1-in-10 chance of a frost after May 9.
- When is the first frost in Mifflintown, PA?
- The average first fall frost (32°F) is October 24. 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 17059?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 185 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.