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Will it freeze in Port Washington in the next 7 nights?
The earliest overnight low at or below 32°F in the available NWS frost forecast is Fri, Nov 6: 31°F (Fri, Nov 6, 6:00 PM CST to Sat, Nov 7, 6:00 AM CST).
Tonight: forecast low 37°F. Above 36°F.
NWS forecast period: Thu, Nov 5, 6:00 PM CST to Fri, Nov 6, 6:00 AM CST.
2 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 37°F Above 36°F · Mostly Cloudy
- Fri, Nov 6 31°F Freeze · Mostly Clear
- Sat, Nov 7 35°F Frost possible · Partly Cloudy
- Sun, Nov 8 37°F Above 36°F · Mostly Clear
- Mon, Nov 9 42°F Above 36°F · Mostly Clear
- Tue, Nov 10 39°F Above 36°F · Partly Cloudy
- Wed, Nov 11 39°F Above 36°F · 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 Port Washington
The median first fall hard-freeze date (28°F) is November 2, from NOAA’s 1991–2020 Climate Normals at Port Washington. 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 26 · May 10 · May 25 | Sep 26 · Oct 10 · Oct 24 | 153 days |
| 32°F freeze | Apr 11 · Apr 27 · May 14 | Oct 6 · Oct 22 · Nov 4 | 176 days |
| 28°F hard freeze | Mar 31 · Apr 13 · Apr 30 | Oct 19 · Nov 2 · Nov 17 | 202 days |
Average high temperature by month
1991–2020 normals at Port Washington
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 Port Washington, WI come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Port Washington (station USC00476764, elevation 594 ft), 1.2 mi from Port Washington. 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 Port Washington
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Grafton, WI | 5.6 mi | Apr 23 | Oct 24 |
| Cedarburg, WI | 8.1 mi | Apr 23 | Oct 24 |
| Mequon, WI | 14 mi | May 6 | Oct 8 |
| Jackson, WI | 15 mi | Apr 30 | Oct 15 |
| West Bend, WI | 15 mi | May 1 | Oct 12 |
| Brown Deer, WI | 16 mi | Apr 26 | Oct 18 |
| Fox Point, WI | 16 mi | Apr 26 | Oct 18 |
| Germantown, WI | 16 mi | May 6 | Oct 8 |
| Glendale, WI | 18 mi | Apr 26 | Oct 18 |
| Whitefish Bay, WI | 19 mi | Apr 26 | Oct 18 |
Frequently asked questions
When is the last frost in Port Washington?
On average, the last spring frost (32°F) in Port Washington is around April 27. In about 1 year in 10 it comes after May 14, and in 9 years in 10 it comes after April 11.
When is the first frost in Port Washington?
The first fall frost (32°F) usually arrives around October 22. There’s a 10% chance of a freeze by October 6 and a 90% chance by November 4.
Can it frost in Port Washington 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 10.
What growing zone is Port Washington?
Port Washington is in USDA Plant Hardiness Zone 5b (average annual extreme minimum temperature −15 to −10°F), based on the 2023 USDA map for ZIP code 53074. See growing zones in Wisconsin.
More: all Wisconsin frost dates · Wisconsin growing zones · frost vs. freeze