USDA Hardiness Zone 6a
Frost Dates for 49401 — Allendale, Michigan
NOAA 1991–2020 normals from Grand Haven Wwtp, MI (605 ft), 15 miles northwest.
Updated
In Allendale, the last spring frost (32°F) is around April 30 in half of years and has passed by May 16 in nine years out of ten. The first fall frost comes around October 24, as early as October 5 one year in ten, leaving a typical freeze-free season of 175 days (NOAA, Grand Haven Wwtp, MI).
- Last spring frost
- April 30
- First fall frost
- October 24
- Growing season
- 175 days
- Hardiness zone
- 6a
50% probability
50% probability
freeze-free, 50%
-10 to -5°F (-23.3 to -20.6°C) coldest night
- First snow
- November 22
- Last snow
- March 28
- Winters with snow
- 100%
- Snow per year
- 48"
median, 1991–2020
median, 1991–2020
20 of 20 observed
NOAA normal
Frost risk by date in Allendale
Half of springs at Grand Haven Wwtp, MI see their last 32°F night by April 30; only one in ten is past it by April 17, and one in ten still has one after May 16. Planting tender crops after May 6 leaves a 30% risk of a frost on them, after May 12 20%, and after May 16 10%. The 16 days between the even-odds date and the one-in-ten date is narrower than at 38% of the 172 Michigan stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 24 in half of years, as early as October 5 one year in ten, and holds off past November 6 one year in ten. A hard freeze of 28°F follows 12 days later, around November 5; in spring the one-in-ten date for 28°F is May 6, 10 days before the 32°F one. The freeze-free season lasts 175 days in a typical year, longer than at 87% of the 172 Michigan stations; it reaches 194 days one year in ten and falls short of 151 one year in ten. On average 134 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 13 days longer, to about May 13, and return around October 9. Severe cold of 16°F or below comes every winter, usually between December 17 and March 16.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 26 | May 2 | May 5 | May 9 | May 13 | May 17 | May 20 | May 24 | May 30 |
| 32°F | Apr 17 | Apr 20 | Apr 24 | Apr 28 | Apr 30 | May 3 | May 6 | May 12 | May 16 |
| 28°F | Apr 4 | Apr 8 | Apr 12 | Apr 16 | Apr 18 | Apr 21 | Apr 25 | Apr 30 | May 6 |
| 24°F | Mar 22 | Mar 30 | Apr 1 | Apr 3 | Apr 6 | Apr 9 | Apr 13 | Apr 17 | Apr 21 |
| 20°F | Mar 10 | Mar 16 | Mar 20 | Mar 24 | Mar 28 | Mar 30 | Apr 2 | Apr 5 | Apr 10 |
| 16°F | Feb 28 | Mar 6 | Mar 10 | Mar 13 | Mar 16 | Mar 20 | Mar 24 | Mar 28 | Mar 31 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 25 | Sep 30 | Oct 3 | Oct 6 | Oct 9 | Oct 12 | Oct 16 | Oct 19 | Oct 25 |
| 32°F | Oct 5 | Oct 11 | Oct 16 | Oct 21 | Oct 24 | Oct 27 | Oct 30 | Nov 1 | Nov 6 |
| 28°F | Oct 21 | Oct 27 | Oct 31 | Nov 2 | Nov 5 | Nov 8 | Nov 12 | Nov 16 | Nov 22 |
| 24°F | Nov 2 | Nov 6 | Nov 11 | Nov 16 | Nov 20 | Nov 24 | Nov 28 | Dec 1 | Dec 8 |
| 20°F | Nov 15 | Nov 22 | Nov 26 | Dec 1 | Dec 3 | Dec 7 | Dec 11 | Dec 17 | Dec 24 |
| 16°F | Nov 29 | Dec 4 | Dec 8 | Dec 12 | Dec 17 | Dec 21 | Dec 24 | Dec 29 | Jan 6 |
Freeze probabilities 1991–2020 at Grand Haven Wwtp, MI, 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 49401 →Compare Allendale with another place →
Compared with the next station
The nearest other station, E Grand Rapids, MI, 16 miles east of Allendale, has a last frost 6 days later (May 6), a first frost 14 days earlier (October 10), a season 18 days shorter.
When it snows in Allendale, Michigan
The first measurable snow (0.1 inch or more) in Allendale usually arrives around November 22, and the last of the season around March 28. Those are the middle dates across the winters of 1991–2020 at Kent City 2 SW, MI, 17.6 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 33 days after the last snow.
Planting calendar for 49401
| When | What to do |
|---|---|
| February 19 – March 5 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 5 – March 19 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 2 – April 16 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 30 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by August 1 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 10 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 24 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 49401 is 15 miles from Grand Haven Wwtp, MI, which stands at 605 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 4 other ZIP codes share the station; its figures are presented in full for 49417 (Grand Haven). The 2023 USDA Plant Hardiness Zone Map lists ZIP 49401 in zone 6a, the band where the coldest night of the year averaged -10 to -5°F (-23.3 to -20.6°C) over 1991–2020; a zone describes winter lows, not frost dates.
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.