Frost dates for 17018Dauphin, PA
The average last spring frost in Dauphin is May 1 and the average first fall frost is October 16, giving a typical growing season of about 168 days. Dates are based on NOAA 1991-2020 climate normals.
- Average last spring frost
- May 1
- Average first fall frost
- Oct 16
- Growing season
- 168 days
Safer after May 20 (1-in-10 risk)
Possible by Oct 3 (1-in-10 risk)
Last frost typically in 179 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 26 · May 12 · May 27 | Sep 23 · Oct 5 · Oct 18 | 145 days | 100% |
| Frost / freeze (32°F) | Apr 15 · May 1 · May 20 | Oct 3 · Oct 16 · Nov 1 | 168 days | 100% |
| Hard freeze (28°F) | Apr 1 · Apr 18 · May 8 | Oct 10 · Oct 30 · Nov 13 | 194 days | 100% |
Planting calendar for Dauphin
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 31 – Jun 6 |
| Tomatoes | Transplant outdoors | May 17 – Jun 26 |
| Peppers | Start seeds indoors | Mar 31 – May 1 |
| Peppers | Transplant outdoors | May 31 – Jul 1 |
| Eggplant | Start seeds indoors | Apr 17 – May 16 |
| Eggplant | Transplant outdoors | May 31 – Jul 1 |
| Cucumbers | Sow outdoors | May 31 – Jul 6 |
| Summer squash | Sow outdoors | May 17 – Jul 1 |
| Winter squash & pumpkins | Sow outdoors | May 31 – Jul 1 |
| Snap beans | Sow outdoors | May 17 – Jul 29 |
| Sweet corn | Sow outdoors | May 17 – Jun 26 |
| Watermelon & cantaloupe | Sow outdoors | May 31 – Jul 1 |
| Okra | Sow outdoors | May 24 – Jun 16 |
| Peas | Sow outdoors (spring) | Mar 31 – May 16 |
| Potatoes | Plant outdoors (spring) | Mar 31 – May 31 |
| Onions | Start seeds indoors (spring) | Feb 17 – Mar 16 |
| Onions | Transplant outdoors (spring) | Apr 17 – May 16 |
| Broccoli | Start seeds indoors (spring) | Mar 13 – Apr 16 |
| Broccoli | Transplant outdoors (spring) | Apr 17 – May 16 |
| Broccoli | Start seeds indoors (fall) | Jun 16 – Jun 26 |
| Broccoli | Transplant outdoors (fall) | Jul 16 – Jul 27 |
| Cabbage | Start seeds indoors (spring) | Mar 3 – Mar 31 |
| Cabbage | Transplant outdoors (spring) | Mar 31 – May 1 |
| Cabbage | Start seeds indoors (fall) | Jun 6 – Jul 6 |
| Cabbage | Transplant outdoors (fall) | Jul 6 – Aug 6 |
| Leaf lettuce | Sow outdoors (spring) | Mar 31 – Jun 16 |
| Leaf lettuce | Sow outdoors (fall) | Jul 6 – Aug 22 |
| Spinach | Sow outdoors (spring) | Mar 24 – May 7 |
| Spinach | Sow outdoors (fall) | Jul 23 – Aug 27 |
| Radishes | Sow outdoors (spring) | Mar 31 – May 21 |
| Radishes | Sow outdoors (fall) | Jul 6 – Sep 6 |
| Kale | Sow outdoors (spring) | Apr 17 – May 7 |
| Kale | Sow outdoors (fall) | Jun 29 – Aug 6 |
| Carrots | Sow outdoors (spring) | May 1 – Jun 16 |
| Carrots | Sow outdoors (fall) | Jun 6 – Jul 22 |
| Garlic | Plant outdoors (fall) | Oct 6 – Nov 6 |
Where these dates come from
ZIP code 17018 is matched to the NOAA station Dehart Dam, PA, 17.4 km away, at 537 ft elevation (76 ft lower than the ZIP code's center). Nearby stations for comparison:
| Station | Elevation | Avg last frost | Avg first frost |
|---|---|---|---|
| Dehart Dam, PA (used) | 537 ft | May 1 | Oct 16 |
| Harrisburg 1 Ne, PA | 420 ft | Apr 15 | Oct 23 |
| Harrisburg Cptl Cy Ap, PA | 340 ft | Apr 9 | Nov 1 |
| Middletown Harrisburg Intl Ap, PA | 312 ft | Apr 9 | Nov 2 |
Frost dates near Dauphin
- Marysville, PA 17053 · last Apr 15, first Oct 23
- New Buffalo, PA 17069 · last Apr 15, first Oct 23
- Summerdale, PA 17093 · last Apr 15, first Oct 23
- Harrisburg, PA 17110 · last Apr 15, first Oct 23
- Enola, PA 17025 · last Apr 15, first Oct 23
- Duncannon, PA 17020 · last Apr 15, first Oct 23
- Halifax, PA 17032 · last May 1, first Oct 16
- Camp Hill, PA 17089 · last Apr 15, first Oct 23
Frequently asked questions
- When is the last frost in Dauphin, PA?
- For ZIP code 17018, the average last spring frost (32°F) is May 1, based on NOAA 1991-2020 climate normals for the Dehart Dam, PA weather station. There is a 1-in-10 chance of a frost after May 20.
- When is the first frost in Dauphin, PA?
- The average first fall frost (32°F) is October 16. There is a 1-in-10 chance of frost by October 3, so tender plants are at risk from that point on.
- How long is the growing season in 17018?
- In half of years, the frost-free season (between the last and first 32°F frost) is at least 168 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.