USDA Hardiness Zone 5a
Frost Dates for 49878 — Rapid River, Michigan
NOAA 1991–2020 normals from Rapid Rvr 4SSE, MI (598 ft), 4 miles southwest.
Updated
In Rapid River, the last spring frost (32°F) is around May 18 in half of years and has passed by June 2 in nine years out of ten. The first fall frost comes around October 4, as early as September 18 one year in ten, leaving a typical freeze-free season of 137 days (NOAA, Rapid Rvr 4SSE, MI).
- Last spring frost
- May 18
- First fall frost
- October 4
- Growing season
- 137 days
- Hardiness zone
- 5a
50% probability
50% probability
freeze-free, 50%
-20 to -15°F (-28.9 to -26.1°C) coldest night
- First snow
- November 10
- Last snow
- April 12
- Winters with snow
- 100%
- Snow per year
- 42.6"
median, 1991–2020
median, 1991–2020
21 of 21 observed
NOAA normal
Frost risk by date in Rapid River
Half of springs at Rapid Rvr 4SSE, MI see their last 32°F night by May 18; only one in ten is past it by May 3, and one in ten still has one after June 2. Planting tender crops after May 25 leaves a 30% risk of a frost on them, after May 29 20%, and after June 2 10%. The 15 days between the even-odds date and the one-in-ten date is narrower than at 55% of the 172 Michigan stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 4 in half of years, as early as September 18 one year in ten, and holds off past October 18 one year in ten. A hard freeze of 28°F follows 13 days later, around October 17; in spring the one-in-ten date for 28°F is May 21, 12 days before the 32°F one. The freeze-free season lasts 137 days in a typical year, shorter than at 76% of the 172 Michigan stations; it reaches 158 days one year in ten and falls short of 117 one year in ten. On average 189 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 31, and return around September 22. Severe cold of 16°F or below comes every winter, usually between November 22 and April 6.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 17 | May 22 | May 26 | May 29 | May 31 | Jun 2 | Jun 4 | Jun 8 | Jun 12 |
| 32°F | May 3 | May 8 | May 12 | May 16 | May 18 | May 22 | May 25 | May 29 | Jun 2 |
| 28°F | Apr 23 | Apr 27 | Apr 30 | May 3 | May 5 | May 9 | May 12 | May 16 | May 21 |
| 24°F | Apr 12 | Apr 17 | Apr 20 | Apr 22 | Apr 25 | Apr 28 | Apr 30 | May 4 | May 9 |
| 20°F | Apr 3 | Apr 6 | Apr 10 | Apr 12 | Apr 14 | Apr 17 | Apr 20 | Apr 23 | Apr 27 |
| 16°F | Mar 25 | Mar 31 | Apr 2 | Apr 4 | Apr 6 | Apr 9 | Apr 11 | Apr 15 | Apr 20 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 5 | Sep 11 | Sep 15 | Sep 19 | Sep 22 | Sep 26 | Sep 30 | Oct 2 | Oct 5 |
| 32°F | Sep 18 | Sep 23 | Sep 28 | Oct 1 | Oct 4 | Oct 6 | Oct 10 | Oct 14 | Oct 18 |
| 28°F | Oct 1 | Oct 6 | Oct 10 | Oct 14 | Oct 17 | Oct 20 | Oct 25 | Oct 28 | Nov 2 |
| 24°F | Oct 17 | Oct 23 | Oct 27 | Oct 30 | Nov 1 | Nov 4 | Nov 7 | Nov 11 | Nov 17 |
| 20°F | Oct 31 | Nov 3 | Nov 7 | Nov 10 | Nov 13 | Nov 16 | Nov 19 | Nov 23 | Nov 28 |
| 16°F | Nov 7 | Nov 13 | Nov 17 | Nov 19 | Nov 22 | Nov 25 | Nov 28 | Dec 1 | Dec 7 |
Freeze probabilities 1991–2020 at Rapid Rvr 4SSE, 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 49878 →Compare Rapid River with another place →
Compared with the next station
The nearest other station, Cornell 5SE, MI, 14 miles southwest of Rapid River and 196 feet higher, has a last frost 1 day later (May 19), a first frost 3 days earlier (October 1), a season 4 days shorter.
When it snows in Rapid River, Michigan
The first measurable snow (0.1 inch or more) in Rapid River usually arrives around November 10, and the last of the season around April 12. Those are the middle dates across the winters of 1991–2020 at Cornell 5SE, MI, 13.8 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 36 days after the last snow.
Planting calendar for 49878
| When | What to do |
|---|---|
| March 9 – March 23 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 23 – April 6 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 20 – May 4 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 18 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 12 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 20 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 4 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 49878 is 4 miles from Rapid Rvr 4SSE, MI, which stands at 598 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. 1 other ZIP code shares the station; its figures are presented in full for 49837 (Gladstone). The 2023 USDA Plant Hardiness Zone Map lists ZIP 49878 in zone 5a, the band where the coldest night of the year averaged -20 to -15°F (-28.9 to -26.1°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.