Frost dates 2026–2027

Frost dates for New Berlin, Wisconsin

Median (50% chance) dates of the last and first 32°F frost, from NOAA 1991–2020 climate normals at Hales Corners/whitnall Park/bo, 5.6 mi away (close match).

Last spring frostMay 3
First fall frostOct 14
162 frost-free days
Last spring frostMay 31 year in 10 after May 19
First fall frostOct 141 year in 10 by Sep 30
Growing season162 daysbetween median 32°F dates
Hardiness zoneZone 5b−15 to −10°F average extreme low

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Will it freeze in New Berlin 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.

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 New Berlin

The median first fall hard-freeze date (28°F) is October 24, from NOAA’s 1991–2020 Climate Normals at Hales Corners/whitnall Park/bo. This is the 50% probability date, not a forecast for this year.

TemperatureLast 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 30 · May 14 · May 29 Sep 22 · Oct 3 · Oct 15 141 days
32°F freeze Apr 18 · May 3 · May 19 Sep 30 · Oct 14 · Oct 26 162 days
28°F hard freeze Apr 8 · Apr 21 · May 9 Oct 8 · Oct 24 · Nov 6 183 days
NOAA NCEI U.S. Climate Normals 1991–2020, station USC00473391. How to read these probabilities.

Average high temperature by month

1991–2020 normals at Hales Corners/whitnall Park/bo

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 New Berlin, WI come from the nearest weather station with freeze statistics in NOAA’s 1991–2020 Climate Normals: Hales Corners/whitnall Park/bo (station USC00473391, elevation 774 ft), 5.6 mi from New Berlin. 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 New Berlin

CityDistanceLast spring frostFirst fall frost
Hales Corners, WI 4.3 mi May 3 Oct 14
West Allis, WI 5.6 mi Apr 26 Oct 22
Elm Grove, WI 5.6 mi Apr 26 Oct 18
Waukesha, WI 6.2 mi May 1 Oct 13
Greenfield, WI 6.2 mi May 3 Oct 14
Waukesha, WI 6.2 mi May 1 Oct 13
Brookfield, WI 6.2 mi Apr 30 Oct 14
Greendale, WI 6.8 mi May 3 Oct 14
Muskego, WI 6.8 mi May 3 Oct 14
Wauwatosa, WI 8.1 mi Apr 26 Oct 18

Frequently asked questions

When is the last frost in New Berlin?

On average, the last spring frost (32°F) in New Berlin is around May 3. In about 1 year in 10 it comes after May 19, and in 9 years in 10 it comes after April 18.

When is the first frost in New Berlin?

The first fall frost (32°F) usually arrives around October 14. There’s a 10% chance of a freeze by September 30 and a 90% chance by October 26.

Can it frost in New Berlin 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 14.

What growing zone is New Berlin?

New Berlin 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 53146. See growing zones in Wisconsin.

More: all Wisconsin frost dates · Wisconsin growing zones · UV index today in New Berlin · frost vs. freeze