USDA Hardiness Zone 6a
Frost Dates for 48618 — Coleman, Michigan
NOAA 1991–2020 normals from Oil City 2S, MI (680 ft), 12 miles south.
Updated
In Coleman, the last spring frost (32°F) is around May 15 in half of years and has passed by June 2 in nine years out of ten. The first fall frost comes around September 29, as early as September 15 one year in ten, leaving a typical freeze-free season of 134 days (NOAA, Oil City 2S, MI).
- Last spring frost
- May 15
- First fall frost
- September 29
- Growing season
- 134 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 21
- Last snow
- April 11
- Winters with snow
- 100%
- Snow per year
- 48.5"
median, 1991–2020
median, 1991–2020
30 of 30 observed
NOAA normal
Frost risk by date in Coleman
Half of springs at Oil City 2S, MI see their last 32°F night by May 15; only one in ten is past it by April 30, and one in ten still has one after June 2. Planting tender crops after May 22 leaves a 30% risk of a frost on them, after May 27 20%, and after June 2 10%. The 18 days between the even-odds date and the one-in-ten date is wider than at 81% of the 172 Michigan stations behind this site's ZIP pages.
In fall the first 32°F night comes by September 29 in half of years, as early as September 15 one year in ten, and holds off past October 11 one year in ten. A hard freeze of 28°F follows 9 days later, around October 8; in spring the one-in-ten date for 28°F is May 19, 14 days before the 32°F one. The freeze-free season lasts 134 days in a typical year, shorter than at 81% of the 172 Michigan stations; it reaches 155 days one year in ten and falls short of 113 one year in ten. On average 171 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 16 days longer, to about May 31, and return around September 18. Severe cold of 16°F or below comes every winter, usually between November 20 and April 1.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | May 14 | May 20 | May 24 | May 27 | May 31 | Jun 2 | Jun 5 | Jun 9 | Jun 13 |
| 32°F | Apr 30 | May 4 | May 8 | May 11 | May 15 | May 19 | May 22 | May 27 | Jun 2 |
| 28°F | Apr 21 | Apr 24 | Apr 28 | Apr 30 | May 2 | May 5 | May 9 | May 14 | May 19 |
| 24°F | Apr 9 | Apr 13 | Apr 17 | Apr 20 | Apr 22 | Apr 25 | Apr 28 | May 1 | May 6 |
| 20°F | Mar 31 | Apr 3 | Apr 6 | Apr 9 | Apr 11 | Apr 14 | Apr 17 | Apr 19 | Apr 24 |
| 16°F | Mar 18 | Mar 22 | Mar 27 | Mar 31 | Apr 1 | Apr 3 | Apr 6 | Apr 9 | Apr 14 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 3 | Sep 9 | Sep 12 | Sep 15 | Sep 18 | Sep 20 | Sep 23 | Sep 26 | Sep 30 |
| 32°F | Sep 15 | Sep 20 | Sep 23 | Sep 26 | Sep 29 | Oct 1 | Oct 3 | Oct 6 | Oct 11 |
| 28°F | Sep 26 | Sep 30 | Oct 2 | Oct 5 | Oct 8 | Oct 12 | Oct 15 | Oct 19 | Oct 24 |
| 24°F | Oct 5 | Oct 11 | Oct 15 | Oct 19 | Oct 23 | Oct 27 | Oct 31 | Nov 2 | Nov 7 |
| 20°F | Oct 21 | Oct 27 | Nov 1 | Nov 3 | Nov 5 | Nov 8 | Nov 12 | Nov 15 | Nov 21 |
| 16°F | Nov 4 | Nov 9 | Nov 12 | Nov 16 | Nov 20 | Nov 24 | Nov 28 | Dec 1 | Dec 7 |
Freeze probabilities 1991–2020 at Oil City 2S, 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 48618 →Compare Coleman with another place →
Compared with the next station
The nearest other station, Central Michigan Univ, MI, 15 miles southwest of Coleman, has a last frost 15 days earlier (April 30), a first frost 21 days later (October 20), a season 37 days longer.
When it snows in Coleman, Michigan
The first measurable snow (0.1 inch or more) in Coleman usually arrives around November 21, and the last of the season around April 11. Those are the middle dates across the winters of 1991–2020 at Gladwin, MI, 16.1 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 34 days after the last snow.
Planting calendar for 48618
| When | What to do |
|---|---|
| March 6 – March 20 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 20 – April 3 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| April 17 – May 1 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| May 15 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 7 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by September 15 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| September 29 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 48618 is 12 miles from Oil City 2S, MI, which stands at 680 feet, the nearest NOAA station that publishes freeze probabilities for 1991–2020. The 2023 USDA Plant Hardiness Zone Map lists ZIP 48618 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.