USDA Hardiness Zone 4b
Frost Dates for 54724 — Bloomer, Wisconsin
NOAA 1991–2020 normals from Bloomer, WI (990 ft), under a mile south.
Updated
In Bloomer, the last spring frost (32°F) is around May 5 in half of years and has passed by May 19 in nine years out of ten. The first fall frost comes around October 3, as early as September 20 one year in ten, leaving a typical freeze-free season of 151 days (NOAA, Bloomer, WI).
- Last spring frost
- May 5
- First fall frost
- October 3
- Growing season
- 151 days
- Hardiness zone
- 4b
50% probability
50% probability
freeze-free, 50%
-25 to -20°F (-31.7 to -28.9°C) coldest night
- First snow
- November 22
- Last snow
- April 3
- Winters with snow
- 100%
- Snow per year
- 41.8"
median, 1991–2020
median, 1991–2020
29 of 29 observed
NOAA normal
Frost risk by date in Bloomer
Half of springs at Bloomer, WI see their last 32°F night by May 5; only one in ten is past it by April 23, and one in ten still has one after May 19. Planting tender crops after May 11 leaves a 30% risk of a frost on them, after May 14 20%, and after May 19 10%. The 14 days between the even-odds date and the one-in-ten date is narrower than at 58% of the 182 Wisconsin stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 3 in half of years, as early as September 20 one year in ten, and holds off past October 17 one year in ten. A hard freeze of 28°F follows 12 days later, around October 15; in spring the one-in-ten date for 28°F is May 8, 11 days before the 32°F one. The freeze-free season lasts 151 days in a typical year, shorter than at 62% of the 182 Wisconsin stations; it reaches 168 days one year in ten and falls short of 132 one year in ten. On average 170 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 11 days longer, to about May 16, and return around September 25. Severe cold of 16°F or below comes every winter, usually between November 15 and March 30.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 3 | May 7 | May 10 | May 14 | May 16 | May 19 | May 22 | May 26 | May 31 |
| 32°F | Apr 23 | Apr 28 | May 1 | May 3 | May 5 | May 8 | May 11 | May 14 | May 19 |
| 28°F | Apr 10 | Apr 16 | Apr 19 | Apr 23 | Apr 26 | Apr 29 | May 1 | May 4 | May 8 |
| 24°F | Apr 2 | Apr 5 | Apr 8 | Apr 12 | Apr 15 | Apr 18 | Apr 21 | Apr 24 | Apr 29 |
| 20°F | Mar 23 | Mar 30 | Apr 1 | Apr 3 | Apr 5 | Apr 8 | Apr 11 | Apr 15 | Apr 20 |
| 16°F | Mar 14 | Mar 20 | Mar 24 | Mar 27 | Mar 30 | Apr 1 | Apr 4 | Apr 7 | Apr 13 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 11 | Sep 15 | Sep 19 | Sep 23 | Sep 25 | Sep 28 | Oct 1 | Oct 3 | Oct 7 |
| 32°F | Sep 20 | Sep 26 | Sep 28 | Oct 1 | Oct 3 | Oct 6 | Oct 9 | Oct 12 | Oct 17 |
| 28°F | Oct 1 | Oct 5 | Oct 9 | Oct 12 | Oct 15 | Oct 17 | Oct 20 | Oct 24 | Oct 28 |
| 24°F | Oct 12 | Oct 17 | Oct 21 | Oct 23 | Oct 26 | Oct 29 | Oct 31 | Nov 3 | Nov 9 |
| 20°F | Oct 23 | Oct 28 | Oct 31 | Nov 1 | Nov 4 | Nov 8 | Nov 11 | Nov 15 | Nov 20 |
| 16°F | Nov 1 | Nov 4 | Nov 8 | Nov 11 | Nov 15 | Nov 18 | Nov 20 | Nov 24 | Nov 28 |
Freeze probabilities 1991–2020 at Bloomer, WI, 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 54724 →Compare Bloomer with another place →
Weather by month in Bloomer
July is the warmest month at Bloomer, WI, averaging 81°F by day and 60°F at night; January is the coldest at 21°F and 3°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 72% of years.
Warmth for growing adds up to 2,357 growing degree days a year (base 50°F), fewer than at 60% of the 182 Wisconsin stations. 33% of them (785) have built up by the end of June, and July adds the most, 635. Precipitation totals 31.7 inches a year, most in June (4.5") and least in February (0.9"); May to September bring 62% of it.
| Month | High °F | Low °F | Precip. in | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|---|
| Jan | 21 | 3 | 1.0 | 100% | 31 | 0 |
| Feb | 26 | 7 | 0.9 | 100% | 27 | 0 |
| Mar | 39 | 19 | 1.6 | 100% | 27 | 7 |
| Apr | 54 | 33 | 2.9 | 100% | 15 | 46 |
| May | 68 | 45 | 3.7 | 72% | 2 | 239 |
| Jun | 77 | 56 | 4.5 | 0% | 0 | 493 |
| Jul | 81 | 60 | 4.1 | 0% | 0 | 635 |
| Aug | 79 | 57 | 4.0 | 0% | 0 | 560 |
| Sep | 71 | 48 | 3.3 | 37% | 1 | 308 |
| Oct | 56 | 36 | 2.8 | 99% | 12 | 65 |
| Nov | 40 | 24 | 1.7 | 100% | 25 | 5 |
| Dec | 27 | 11 | 1.2 | 100% | 30 | 0 |
Monthly normals 1991–2020 at Bloomer, WI (990 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, Eau Claire Regional Airport, WI, 16 miles south of Bloomer, has a last frost 3 days later (May 8), a first frost 1 day later (October 4), a season 2 days shorter.
When it snows in Bloomer, Wisconsin
The first measurable snow (0.1 inch or more) in Bloomer usually arrives around November 22, and the last of the season around April 3. Those are the middle dates across the winters of 1991–2020 at Bloomer, WI, 0.8 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 32 days after the last snow.
Planting calendar for 54724
| When | What to do |
|---|---|
| February 24 – March 10 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 10 – March 24 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 7 – April 21 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 5 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 11 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 19 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 3 onward | Plant 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 54724 is under a mile from Bloomer, WI, which stands at 990 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 2 other ZIP codes share the station. The 2023 USDA Plant Hardiness Zone Map lists ZIP 54724 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 Wisconsin →
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.