Last and first frost dates in Baltimore

When is the last frost in Baltimore?

The last frost in Baltimore usually comes around 31 March: 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 10 March, while corn waits until 7 April. The first autumn frost follows around 22 November, about 236 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.

What planting zone is Baltimore?

The official USDA map (2023, 1991–2020 data) puts the centre of Baltimore (ZIP 21202) in zone 8a. Zone 8a stands for an average coldest night of 10 to 15 °F (-12.2 to -9.4 °C), so perennials hardy to zone 8a or a colder zone should come through a typical winter here.

Check the official USDA map for Baltimore: USDA Plant Hardiness Zone Map.

When the soil warms up in Baltimore

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 13 days before the last spring frost and 15 °C 16 days after it.

Frost dates near Baltimore

Of the nearest cities on our list, the last spring frost ends earliest in Dover (28 March) and latest in Harrisburg (10 April).

Seeds, seedlings and markets in Baltimore

Within 15 km of Baltimore OpenStreetMap lists 8 garden centres, 4 plant nurseries, 20 markets and 3 farm shops (collected 20 October 2026). The nearest garden centre to the city centre is B.Willow, 4 km away.

• B.Willow — garden centre
  West 27th Street 220, 21211 Baltimore · Mon–Sat 11:00–20:00; Sun 11:00–19:00 · 4 km
• TreeBaltimore Nursery — plant nursery
  Shop Road 3101, 21217 Baltimore · 5 km · treebaltimore.org
• Baltimore Farmers Market & Bazaar — market
  East Saratoga Street 400, 21202 Baltimore · Apr–Dec: Sun 07:00–12:00 · 0 km · promotionandarts.org
• Fruitland — farm shop
  Eastern Boulevard 106, 21221 Essex · 11 km
• Green Neighbor — garden centre
  Mon–Thu 12:00–17:00; Fri–Sun 09:30–17:00 · 5 km
• Herring Run Nursery — plant nursery
  Hillen Rd 6131, 21239 Baltimore · Wed–Sun 10:00–15:00 · 10 km · bluewaterbaltimore.org

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

Places: © OpenStreetMap contributors, ODbL.

Weather in Baltimore by month

Average weather in Baltimore over 2016–2025: the warmest month is July. Months that average 20 °C or more by day: May–September (21.9–30 °C). Months that average 30 °C or more by day: July (30 °C). Nights average below 0 °C in January (-1.2 °C). About 1501 mm of rain falls in a year, on 136 days; July is the wettest month (191 mm) and January the driest (87 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).