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Will it freeze in Williamsport in the next 7 nights?
The earliest overnight low at or below 32°F in the available NWS frost forecast is Wed, Nov 11: 31°F (Wed, Nov 11, 6:00 PM EST to Thu, Nov 12, 6:00 AM EST).
Tonight: forecast low 48°F. Above 36°F.
NWS forecast period: Thu, Nov 5, 6:00 PM EST to Fri, Nov 6, 6:00 AM EST.
4 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 48°F Above 36°F · Areas Of Fog
- Fri, Nov 6 43°F Above 36°F · Mostly Cloudy
- Sat, Nov 7 40°F Above 36°F · Chance Light Rain then Mostly Cloudy
- Sun, Nov 8 36°F Frost possible · Mostly Clear
- Mon, Nov 9 35°F Frost possible · Mostly Clear
- Tue, Nov 10 35°F Frost possible · Mostly Clear
- Wed, Nov 11 31°F Freeze · 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 Williamsport
The median first fall hard-freeze date (28°F) is November 4, from NOAA’s 1991–2020 Climate Normals at Williamsport 2. 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 21 · May 7 · May 23 | Sep 29 · Oct 11 · Oct 25 | 158 days |
| 32°F freeze | Apr 10 · Apr 25 · May 12 | Oct 8 · Oct 24 · Nov 5 | 181 days |
| 28°F hard freeze | Mar 29 · Apr 10 · Apr 25 | Oct 20 · Nov 4 · Nov 18 | 206 days |
Average high temperature by month
1991–2020 normals at Williamsport 2
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 Williamsport, PA come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Williamsport 2 (station USC00369735, elevation 525 ft), 2.8 mi from Williamsport. 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 Williamsport
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| South Williamsport, PA | 1.9 mi | Apr 25 | Oct 24 |
| Milton, PA | 19 mi | Apr 26 | Oct 20 |
| Lewisburg, PA | 21 mi | Apr 26 | Oct 20 |
| Lock Haven, PA | 23 mi | Apr 30 | Oct 20 |
| Sunbury, PA | 29 mi | Apr 30 | Oct 13 |
| Selinsgrove, PA | 32 mi | Apr 25 | Oct 22 |
| Bloomsburg, PA | 34 mi | Apr 27 | Oct 20 |
| Shamokin, PA | 40 mi | Apr 27 | Oct 20 |
| Berwick, PA | 43 mi | May 4 | Oct 11 |
| Bellefonte, PA | 44 mi | Apr 20 | Oct 26 |
Frequently asked questions
When is the last frost in Williamsport?
On average, the last spring frost (32°F) in Williamsport is around April 25. In about 1 year in 10 it comes after May 12, and in 9 years in 10 it comes after April 10.
When is the first frost in Williamsport?
The first fall frost (32°F) usually arrives around October 24. There’s a 10% chance of a freeze by October 8 and a 90% chance by November 5.
Can it frost in Williamsport 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 May 7.
What growing zone is Williamsport?
Williamsport is in USDA Plant Hardiness Zone 6b (average annual extreme minimum temperature −5 to 0°F), based on the 2023 USDA map for ZIP code 17702. See growing zones in Pennsylvania.
More: all Pennsylvania frost dates · Pennsylvania growing zones · UV index today in Williamsport · frost vs. freeze