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Will it freeze in Brookfield in the next 7 nights?
The earliest overnight low at or below 32°F in the available NWS frost forecast is Fri, Nov 6: 29°F (Fri, Nov 6, 6:00 PM CST to Sat, Nov 7, 6:00 AM CST).
Tonight: forecast low 36°F. Frost possible.
NWS forecast period: Thu, Nov 5, 6:00 PM CST to Fri, Nov 6, 6:00 AM CST.
4 of the next 7 nights are forecast at 36°F or colder, cold enough for frost on exposed plants.
- Tonight 36°F Frost possible · Mostly Cloudy
- Fri, Nov 6 29°F Freeze · Mostly Clear
- Sat, Nov 7 33°F Frost possible · Partly Cloudy
- Sun, Nov 8 35°F Frost possible · Mostly Clear
- Mon, Nov 9 41°F Above 36°F · Mostly Clear
- Tue, Nov 10 37°F Above 36°F · Partly Cloudy
- Wed, Nov 11 38°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 Brookfield
The median first fall hard-freeze date (28°F) is October 25, from NOAA’s 1991–2020 Climate Normals at Brookfield Wastewater Plant. 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 28 · May 10 · May 29 | Sep 21 · Oct 3 · Oct 17 | 142 days |
| 32°F freeze | Apr 16 · Apr 30 · May 15 | Sep 28 · Oct 14 · Oct 27 | 164 days |
| 28°F hard freeze | Apr 5 · Apr 19 · May 3 | Oct 10 · Oct 25 · Nov 7 | 188 days |
Average high temperature by month
1991–2020 normals at Brookfield Wastewater Plant
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 Brookfield, WI come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Brookfield Wastewater Plant (station USC00471062, elevation 830 ft), 3.1 mi from Brookfield. 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 Brookfield
| City | Distance | Last spring frost | First fall frost |
|---|---|---|---|
| Elm Grove, WI | 1.9 mi | Apr 26 | Oct 18 |
| Wauwatosa, WI | 4.3 mi | Apr 26 | Oct 18 |
| West Allis, WI | 6.2 mi | Apr 26 | Oct 22 |
| Pewaukee, WI | 6.2 mi | Apr 30 | Oct 14 |
| New Berlin, WI | 6.2 mi | May 3 | Oct 14 |
| Menomonee Falls, WI | 6.8 mi | May 6 | Oct 8 |
| Pewaukee, WI | 7.5 mi | Apr 30 | Oct 14 |
| Sussex, WI | 7.5 mi | Apr 30 | Oct 16 |
| Waukesha, WI | 7.5 mi | May 1 | Oct 13 |
| Milwaukee, WI | 7.5 mi | Apr 26 | Oct 18 |
Frequently asked questions
When is the last frost in Brookfield?
On average, the last spring frost (32°F) in Brookfield is around April 30. In about 1 year in 10 it comes after May 15, and in 9 years in 10 it comes after April 16.
When is the first frost in Brookfield?
The first fall frost (32°F) usually arrives around October 14. There’s a 10% chance of a freeze by September 28 and a 90% chance by October 27.
Can it frost in Brookfield 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 Brookfield?
Brookfield 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 53005. See growing zones in Wisconsin.
More: all Wisconsin frost dates · Wisconsin growing zones · UV index today in Brookfield · frost vs. freeze