Last and first frost dates in Duluth

When is the last frost in Duluth?

The last frost in Duluth usually comes around 28 April: that is the median of 2016–2025, so in about half of those years the last night at or below 0 °C came later. Hardy crops start before it and frost-tender ones only after it: in the table below arugula can go into open ground from 7 April, while corn waits until 25 May. The first autumn frost follows around 28 October, about 183 days later: harvest or cover frost-tender crops before then.

When to sow and plant

Planting out: a week after the last frost once the soil is warm enough for the crop; frost-hardy crops three weeks before it; an unheated greenhouse three weeks earlier. Seedlings are sown so they are ready on that day. Each window starts on the Greenly calendar date and ends on the last day that still leaves the crop’s days to harvest (from its card) before the average first autumn frost, plus six weeks of picking for crops harvested over weeks (tomatoes, peppers, aubergines, cucumbers, courgettes, pumpkins, watermelons, beans) — our rule; earlier in the window is safer.

When the soil warms up in Duluth

The day the top 7 cm of soil first averages each temperature over a week, median of 2016–2025 (ERA5 via Open-Meteo). The soil reaches 10 °C 17 days after the last spring frost and 15 °C 38 days after it.

Frost dates near Duluth

Of the nearest cities on our list, the last spring frost ends earliest in Minneapolis (28 April) and latest in Thunder Bay (11 May).

Seeds, seedlings and markets in Duluth

Within 15 km of Duluth OpenStreetMap lists 1 garden centre and 1 market (collected 28 October 2026). The nearest garden centre to the city centre is Growing Duluth, 7 km away.

• Growing Duluth — garden centre
  Cody Street 6616, 55807 Duluth · 7 km · growingduluth.com
• Farmer's Market — market
  East 3rd Street 1324, 55805 Duluth · May–Oct: Wed 14:00–17:00, Sat 08:00–12:00; public holidays · 3 km · duluthfarmersmarket.com

• Where to buy seeds and seedlings in Duluth
• Selling your own harvest in the United States

Places: © OpenStreetMap contributors, ODbL.

Weather in Duluth by month

Average weather in Duluth over 2016–2025: the warmest month is July. Months that average 20 °C or more by day: June–September (21–25.5 °C). Nights average below 0 °C in November–March (-11.8–-0.9 °C). About 818 mm of rain falls in a year, on 113 days; September is the wettest month (90 mm) and January the driest (26 mm).

Average of the daily highs and lows, rain per month and days with at least 1 mm (ERA5 via Open-Meteo, the same grid cell as the frost dates).

Planted in autumn

From a month before the first autumn frost, so the roots grow before winter, to the late-planting limit on each crop’s page (about two weeks before the ground freezes, by ten years of weather).