USDA Hardiness Zone 6a
Frost Dates for 48160 — Milan, Michigan
NOAA 1991–2020 normals from Milan Wwtp, MI (680 ft), under a mile east.
Updated
In Milan, the last spring frost (32°F) is around April 26 in half of years and has passed by May 9 in nine years out of ten. The first fall frost comes around October 19, as early as October 2 one year in ten, leaving a typical freeze-free season of 175 days (NOAA, Milan Wwtp, MI).
- Last spring frost
- April 26
- First fall frost
- October 19
- 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
- December 6
- Last snow
- March 18
- Winters with snow
- 100%
- Snow per year
- —
median, 1991–2020
median, 1991–2020
15 of 15 observed
NOAA normal
Frost risk by date in Milan
Half of springs at Milan Wwtp, MI see their last 32°F night by April 26; only one in ten is past it by April 13, and one in ten still has one after May 9. Planting tender crops after May 1 leaves a 30% risk of a frost on them, after May 4 20%, and after May 9 10%. The 13 days between the even-odds date and the one-in-ten date is narrower than at 95% of the 172 Michigan stations behind this site's ZIP pages.
In fall the first 32°F night comes by October 19 in half of years, as early as October 2 one year in ten, and holds off past November 3 one year in ten. A hard freeze of 28°F follows 13 days later, around November 1; in spring the one-in-ten date for 28°F is April 30, 9 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 197 days one year in ten and falls short of 155 one year in ten. On average 137 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 9 days longer, to about May 5, and return around October 7. Severe cold of 16°F or below comes every winter, usually between December 6 and March 16.
| Low | 90% | 80% | 70% | 60% | 50% | 40% | 30% | 20% | 10% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Apr 23 | Apr 27 | Apr 30 | May 2 | May 5 | May 7 | May 10 | May 14 | May 19 |
| 32°F | Apr 13 | Apr 17 | Apr 20 | Apr 23 | Apr 26 | Apr 29 | May 1 | May 4 | May 9 |
| 28°F | Apr 2 | Apr 6 | Apr 9 | Apr 12 | Apr 15 | Apr 18 | Apr 21 | Apr 25 | Apr 30 |
| 24°F | Mar 19 | Mar 26 | Mar 30 | Apr 2 | Apr 4 | Apr 6 | Apr 9 | Apr 13 | Apr 19 |
| 20°F | Mar 10 | Mar 15 | Mar 19 | Mar 22 | Mar 26 | Mar 29 | Mar 31 | Apr 3 | Apr 7 |
| 16°F | Feb 28 | Mar 6 | Mar 10 | Mar 13 | Mar 16 | Mar 19 | Mar 23 | Mar 27 | Mar 31 |
| Low | 10% | 20% | 30% | 40% | 50% | 60% | 70% | 80% | 90% |
|---|---|---|---|---|---|---|---|---|---|
| 36°F | Sep 24 | Sep 29 | Oct 2 | Oct 4 | Oct 7 | Oct 10 | Oct 12 | Oct 15 | Oct 20 |
| 32°F | Oct 2 | Oct 8 | Oct 12 | Oct 16 | Oct 19 | Oct 22 | Oct 25 | Oct 29 | Nov 3 |
| 28°F | Oct 16 | Oct 21 | Oct 25 | Oct 29 | Nov 1 | Nov 2 | Nov 5 | Nov 9 | Nov 14 |
| 24°F | Oct 30 | Nov 2 | Nov 5 | Nov 9 | Nov 12 | Nov 15 | Nov 18 | Nov 22 | Nov 28 |
| 20°F | Nov 8 | Nov 13 | Nov 17 | Nov 21 | Nov 24 | Nov 28 | Dec 1 | Dec 5 | Dec 12 |
| 16°F | Nov 19 | Nov 25 | Nov 30 | Dec 3 | Dec 6 | Dec 10 | Dec 14 | Dec 19 | Dec 24 |
Freeze probabilities 1991–2020 at Milan 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 48160 →Compare Milan with another place →
Weather by month in Milan
July is the warmest month at Milan Wwtp, MI, averaging 84°F by day and 63°F at night; January is the coldest at 32°F and 17°F. A freezing night is all but certain in every month from November to April (a 90% chance or more). From June to September the chance of a 32°F night stays under 10% each month. In spring, May still brings one in 32% of years.
Warmth for growing adds up to 2,886 growing degree days a year (base 50°F), more than at 88% of the 172 Michigan stations. 33% of them (961) have built up by the end of June, and July adds the most, 716.
| Month | High °F | Low °F | 32°F night | Nights ≤ 32°F | GDD 50°F |
|---|---|---|---|---|---|
| Jan | 32 | 17 | 100% | 28 | 1 |
| Feb | 34 | 18 | 100% | 26 | 1 |
| Mar | 45 | 26 | 100% | 24 | 15 |
| Apr | 58 | 37 | 99% | 9 | 75 |
| May | 70 | 49 | 32% | 1 | 304 |
| Jun | 79 | 58 | 0% | 0 | 566 |
| Jul | 84 | 63 | 0% | 0 | 716 |
| Aug | 81 | 61 | 0% | 0 | 646 |
| Sep | 75 | 53 | 7% | <1 | 408 |
| Oct | 62 | 41 | 85% | 5 | 136 |
| Nov | 48 | 32 | 100% | 17 | 17 |
| Dec | 36 | 24 | 100% | 27 | 2 |
Monthly normals 1991–2020 at Milan Wwtp, MI (680 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, Milan 4 ESE, MI, 4 miles east of Milan, has a last frost 7 days later (May 3), a first frost 9 days earlier (October 10), a season 17 days shorter.
When it snows in Milan, Michigan
The first measurable snow (0.1 inch or more) in Milan usually arrives around December 6, and the last of the season around March 18. Those are the middle dates across the winters of 1991–2020 at Milan 4 ESE, MI, 3.5 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 39 days after the last snow.
Planting calendar for 48160
| When | What to do |
|---|---|
| February 15 – March 1 | Start peppers and aubergines indoorsThey need eight to ten weeks under lights before they can go out. |
| March 1 – March 15 | Start tomatoes indoorsSix to eight weeks gives a transplant big enough to set fruit early. |
| March 29 – April 12 | Sow peas, spinach, lettuce, radish outdoorsThese tolerate light frost and prefer to germinate in cool soil. |
| April 26 onward | Transplant tomatoes, peppers, basil, squash, cucumbersThe average last freeze has passed — still watch the actual forecast. |
| by July 27 | Sow the autumn crop of carrots, beets and brassicasThey need about twelve weeks to size up before growth stops. |
| by October 5 | Harvest tender crops, or be ready to cover themA first freeze two weeks early is well within normal variation. |
| October 19 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 48160 is under a mile from Milan Wwtp, 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 48160 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.