USDA Hardiness Zone 6a
Frost Dates for 48416 — Brown City, Michigan
Averages from Yale 1 Nnw, Mi US, the nearest reporting station, 10.4 miles away.
Plant tender crops after May 12, and expect the first autumn freeze around October 5. That leaves about 147 frost-free days.
- Last spring frost
- May 12
- First fall frost
- October 5
- Growing season
- 147 days
- Hardiness zone
- 6a
50% probability
50% probability
frost-free
-10 to -5°F annual low
Planting calendar for 48416
| When | What to do |
|---|---|
| March 3 – March 17 | Start peppers and aubergines indoors They need eight to ten weeks under lights before they can go out. |
| March 17 – March 31 | Start tomatoes indoors Six to eight weeks gives a transplant big enough to set fruit early. |
| April 14 – April 28 | Sow peas, spinach, lettuce, radish outdoors These tolerate light frost and prefer to germinate in cool soil. |
| May 12 onward | Transplant tomatoes, peppers, basil, squash, cucumbers The average last freeze has passed — still watch the actual forecast. |
| by July 13 | Sow the autumn crop of carrots, beets and brassicas They need about twelve weeks to size up before growth stops. |
| by September 21 | Harvest tender crops, or be ready to cover them A first freeze two weeks early is well within normal variation. |
| October 5 onward | Plant garlic, mulch beds, lift tender bulbs Garlic wants a cold spell; bare soil loses structure over winter. |
What these dates mean
Wait until after May 12 to put tender plants — tomatoes, peppers, basil, squash — in the ground. That is the date by which half of years in Brown City, Michigan are past their last freeze. Harvest before October 5, which leaves roughly 147 frost-free days.
ZIP 48416 sits in USDA hardiness zone 6a, meaning the average coldest night of the year falls between -10 to -5°F. Zone decides what survives the winter; frost dates decide when to plant each spring. They are different questions, and a plant can pass one and fail the other.
These are thirty-year NOAA averages for 1991–2020, not a forecast. Any individual year can frost two to three weeks either side of these dates, so check the actual forecast before planting out.