Skip to content
Frost Date Finder

USDA Hardiness Zone 4b

Frost Dates for 55912 — Austin, Minnesota

NOAA 1991–2020 normals from Austin Waste Wtp Facility, MN (1,199 ft), 1 miles south.

Updated

In Austin, the last spring frost (32°F) is around April 30 in half of years and has passed by May 11 in nine years out of ten. The first fall frost comes around October 5, as early as September 22 one year in ten, leaving a typical freeze-free season of 158 days (NOAA, Austin Waste Wtp Facility, MN).

Last spring frost
April 30

50% probability

First fall frost
October 5

50% probability

Growing season
158 days

freeze-free, 50%

Hardiness zone
4b

-25 to -20°F (-31.7 to -28.9°C) coldest night

First snow
November 11

median, 1991–2020

Last snow
April 4

median, 1991–2020

Winters with snow
100%

29 of 29 observed

Snow per year
43.4"

NOAA normal

ShareXFacebookWhatsAppEmail

Frost risk by date in Austin

Half of springs at Austin Waste Wtp Facility, MN see their last 32°F night by April 30; only one in ten is past it by April 14, and one in ten still has one after May 11. Planting tender crops after May 4 leaves a 30% risk of a frost on them, after May 7 20%, and after May 11 10%. The 11 days between the even-odds date and the one-in-ten date is the narrowest of the 142 Minnesota stations behind this site's ZIP pages.

In fall the first 32°F night comes by October 5 in half of years, as early as September 22 one year in ten, and holds off past October 19 one year in ten. A hard freeze of 28°F follows 12 days later, around October 17; in spring the one-in-ten date for 28°F is May 1, 10 days before the 32°F one. The freeze-free season lasts 158 days in a typical year, longer than at 72% of the 142 Minnesota stations; it reaches 178 days one year in ten and falls short of 140 one year in ten. On average 165 nights a year drop to 32°F or below. Nights of 36°F, when frost can still settle on leaves in low, open spots, continue 8 days longer, to about May 8, and return around September 27. Severe cold of 16°F or below comes every winter, usually between November 13 and March 24.

Spring: the chance of another night this cold after the date
Low90%80%70%60%50%40%30%20%10%
36°FApr 26Apr 30May 3May 6May 8May 10May 13May 16May 21
32°FApr 14Apr 20Apr 24Apr 27Apr 30May 2May 4May 7May 11
28°FApr 4Apr 8Apr 12Apr 15Apr 18Apr 21Apr 23Apr 27May 1
24°FMar 25Mar 31Apr 3Apr 5Apr 8Apr 11Apr 15Apr 19Apr 24
20°FMar 15Mar 20Mar 25Mar 29Apr 1Apr 3Apr 6Apr 10Apr 17
16°FMar 9Mar 13Mar 17Mar 20Mar 24Mar 27Mar 31Apr 3Apr 7
Fall: the chance the first night this cold has come by the date
Low10%20%30%40%50%60%70%80%90%
36°FSep 14Sep 19Sep 22Sep 25Sep 27Sep 30Oct 3Oct 5Oct 10
32°FSep 22Sep 26Sep 30Oct 3Oct 5Oct 9Oct 12Oct 15Oct 19
28°FOct 1Oct 5Oct 10Oct 13Oct 17Oct 19Oct 22Oct 25Oct 30
24°FOct 14Oct 18Oct 22Oct 24Oct 28Oct 30Nov 1Nov 4Nov 10
20°FOct 23Oct 29Nov 1Nov 2Nov 5Nov 8Nov 10Nov 14Nov 19
16°FNov 1Nov 4Nov 7Nov 10Nov 13Nov 16Nov 19Nov 23Nov 27

Freeze probabilities 1991–2020 at Austin Waste Wtp Facility, MN, from NOAA NCEI U.S. Climate Normals. Where a temperature is reached in fewer than 99.5% of years, the dates describe only the years that reach it. Not a forecast.

Frost risk on any date in 55912 →Compare Austin with another place →

Frost risk through the year in Austin

Frost curve for Austin, Minnesota (Austin Waste Wtp Facility, MN, NOAA 1991–2020): the chance of another 32°F night falls from 90% on April 14 to 50% on April 30 and 10% on May 11; the chance that the first fall one has come rises from 10% on September 22 to 50% on October 5 and 90% on October 19.

In Austin, the spring curve drops under 10% on May 11 and the fall curve passes 10% on September 22, 134 days later; that gap is longer than at 77% of the 142 Minnesota stations with frost dates. The spring risk falls from 90% to 10% over 27 days (April 14 to May 11) and the fall risk climbs from 10% to 90% over 27 days (September 22 to October 19): both ends of the season vary about as much. At Albert Lea 3SE, MN, 17 miles west, the same gap runs from May 10 to September 26, 5 days longer.

Chance of a frost after each planting date in Austin
Planted onAnother 32°F night28°F night
Apr 1687%57%
Apr 2373%30%
Apr 3050% date50%13%
May 720%under 10%
May 14under 10%under 10%
May 21under 10%under 10%

Weather by month in Austin

July is the warmest month at Austin Waste Wtp Facility, MN, averaging 81°F by day and 61°F at night; January is the coldest at 22°F and 5°F. A freezing night is all but certain in every month from October to April (a 90% chance or more). From June to August the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 46% of years.

Warmth for growing adds up to 2,548 growing degree days a year (base 50°F), more than at 65% of the 142 Minnesota stations. 34% of them (868) have built up by the end of June, and July adds the most, 651. Precipitation totals 36.3 inches a year, most in June (5.1") and least in January (1.1"); May to September bring 63% of it.

Monthly normals 1991–2020 at Austin Waste Wtp Facility, MN
MonthHigh °FLow °FPrecip. in32°F nightNights ≤ 32°FGDD 50°F
Jan2251.1100%310
Feb2691.1100%270
Mar39232.0100%2610
Apr55353.7100%1360
May68485.046%2262
Jun78585.10%0537
Jul81614.90%0651
Aug79594.10%0580
Sep72503.632%1346
Oct58382.699%1194
Nov42251.8100%249
Dec28131.3100%300

Monthly normals 1991–2020 at Austin Waste Wtp Facility, MN (1,199 ft), NOAA NCEI. "32°F night": chance of at least one in the month. GDD: growing degree days, base 50°F.

Compared with the next station

The nearest other station, Albert Lea 3SE, MN, 17 miles west of Austin, has a last frost 3 days earlier (April 27), a first frost 4 days later (October 9), a season 6 days longer.

Frost dates for 56007 (Albert Lea) →

When it snows in Austin, Minnesota

The first measurable snow (0.1 inch or more) in Austin usually arrives around November 11, and the last of the season around April 4. Those are the middle dates across the winters of 1991–2020 at Austin Waste Wtp Facility, MN, 1.3 miles away: half of years saw snow earlier, half later. Every one of those winters saw snow. The last 32°F night of spring typically comes 26 days after the last snow.

Planting calendar for 55912

What to do and when, from the 50% frost dates for Austin, Minnesota
WhenWhat to do
February 19 – March 5Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out.
March 5 – March 19Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early.
April 2 – April 16Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil.
April 30 onwardTransplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast.
by July 13Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops.
by September 21Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation.
October 5 onwardPlant garlic, mulch beds, lift tender bulbsGarlic wants a cold spell; bare soil loses structure over winter.

The weeks before and after the 50% dates are general rules of thumb, not NOAA figures; a seed packet gives the timing for each variety.

Where these figures come from

ZIP 55912 is 1 mile from Austin Waste Wtp Facility, MN, which stands at 1,199 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 55912 in zone 4b, the band where the coldest night of the year averaged -25 to -20°F (-31.7 to -28.9°C) over 1991–2020; a zone describes winter lows, not frost dates.

Frost dates across Minnesota →

Hardiness zone and temperature range: USDA Plant Hardiness Zone Map 2023 (USDA-ARS, Oregon State University), ZIP-code listing, unchanged. °C converted from °F by this site.

Thirty-year averages, not a forecast: check the forecast before planting out. How stations are matched and which pages are offered to search engines: methodology.

Other zone 4b places in Minnesota