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Will it freeze in Mechanicsburg in the next 7 nights?
No overnight lows at or below 32°F are forecast in Mechanicsburg during the next 7 nights in the available NWS frost forecast.
Tonight: forecast low 55°F. Above 36°F.
NWS forecast period: Thu, Nov 5, 6:00 PM EST to Fri, Nov 6, 6:00 AM EST.
1 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 55°F Above 36°F · Chance Light Rain then Mostly Cloudy
- Fri, Nov 6 46°F Above 36°F · Partly Cloudy
- Sat, Nov 7 41°F Above 36°F · Slight Chance Light Rain then Partly Cloudy
- Sun, Nov 8 38°F Above 36°F · Mostly Clear
- Mon, Nov 9 37°F Above 36°F · Mostly Clear
- Tue, Nov 10 38°F Above 36°F · Mostly Clear
- Wed, Nov 11 35°F Frost possible · Partly Cloudy
Overnight lows from the National Weather Service forecast for this location. This covers the available forecast window, not the first freeze of the whole season. Frost can form above 32°F on clear, calm nights.
Frost and freeze probabilities
Freeze dates shift from year to year. Spring percentages describe the chance of a freeze after the stated date; fall percentages describe the chance of a freeze by that date. The 10% spring date is the cautious one: a later freeze happens about 1 year in 10.
These dates describe historical probabilities, not this year’s forecast or the earliest and latest possible freezes. Different weather stations or probability thresholds can produce different published dates for the same city.
Average first hard freeze in Mechanicsburg
The median first fall hard-freeze date (28°F) is November 12, from NOAA’s 1991–2020 Climate Normals at Harrisburg Cptl Cy Airport. This is the 50% probability date, not a forecast for this year.
| Temperature | Last spring date 90% · 50% · 10% chance of a later freeze | First fall date 10% · 50% · 90% chance of an earlier freeze | Season |
|---|---|---|---|
| 36°F frost possible | Apr 9 · Apr 22 · May 10 | Oct 7 · Oct 20 · Nov 3 | 180 days |
| 32°F freeze | Mar 27 · Apr 9 · Apr 25 | Oct 16 · Nov 1 · Nov 15 | 205 days |
| 28°F hard freeze | Mar 13 · Mar 29 · Apr 9 | Oct 28 · Nov 12 · Dec 1 | 231 days |
Average high temperature by month
1991–2020 normals at Harrisburg Cptl Cy Airport
Average low temperature by month
Months with lows near or below freezing carry frost risk
Where these frost dates come from
The frost dates for Mechanicsburg, PA come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Harrisburg Cptl Cy Airport (station USW00014751, elevation 340 ft), 8.1 mi from Mechanicsburg. Local conditions (valleys, hilltops, distance to water, city heat) can shift frost dates by days or weeks. The hardiness zone is from the 2023 USDA Plant Hardiness Zone Map (USDA ARS and Oregon State University PRISM). See our methodology.
Frost dates near Mechanicsburg
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Camp Hill, PA | 4.3 mi | Apr 15 | Oct 23 |
| New Cumberland, PA | 6.8 mi | Apr 9 | Nov 1 |
| Harrisburg, PA | 8.1 mi | Apr 15 | Oct 23 |
| Steelton, PA | 9.3 mi | Apr 9 | Nov 1 |
| Carlisle, PA | 11 mi | Apr 23 | Oct 18 |
| Middletown, PA | 15 mi | Apr 9 | Nov 2 |
| Elizabethtown, PA | 22 mi | Apr 9 | Nov 2 |
| West York, PA | 22 mi | Apr 26 | Oct 19 |
| York, PA | 22 mi | Apr 26 | Oct 19 |
| Palmyra, PA | 23 mi | Apr 20 | Oct 25 |
Frequently asked questions
When is the last frost in Mechanicsburg?
On average, the last spring frost (32°F) in Mechanicsburg is around April 9. In about 1 year in 10 it comes after April 25, and in 9 years in 10 it comes after March 27.
When is the first frost in Mechanicsburg?
The first fall frost (32°F) usually arrives around November 1. There’s a 10% chance of a freeze by October 16 and a 90% chance by November 15.
Can it frost in Mechanicsburg after the last frost date?
Yes. Frost can form on clear, calm nights even when the air stays above 32°F. Temperatures of 36°F or lower, cold enough for frost on exposed plants, have a 50% chance of occurring after April 22.
What growing zone is Mechanicsburg?
Mechanicsburg is in USDA Plant Hardiness Zone 7a (average annual extreme minimum temperature 0 to 5°F), based on the 2023 USDA map for ZIP code 17055. See growing zones in Pennsylvania.
More: all Pennsylvania frost dates · Pennsylvania growing zones · frost vs. freeze