Last and first frost dates in Kumamoto

When is the last frost in Kumamoto?

The last frost in Kumamoto usually comes around 18 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 25 February, while corn waits until 25 March. The first autumn frost follows around 3 December, about 260 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 Kumamoto

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

Frost dates near Kumamoto

Of the nearest cities on our list, the last spring frost ends earliest in Kagoshima (24 January) and latest in Hiroshima (9 April).

Seeds, seedlings and markets in Kumamoto

Within 15 km of Kumamoto OpenStreetMap lists 3 garden centres, 5 markets and 2 farm shops (collected 28 October 2026). The nearest garden centre to the city centre is ガーデン館, 12 km away.

• ガーデン館 — garden centre
  09:00–21:00 · 12 km · nishimuta.co.jp
• フルーツの里　田原坂 — market
  09:00–17:00 || "年末年始" · 10 km
• 合志物産館 志来菜彩 — farm shop
  09:00–19:00 · 11 km
• 植木青果市場 — market
  08:30–22:00; Tue, Sat, public holidays -1 day closed · 13 km

• Where to buy seeds and seedlings in Kumamoto

Places: © OpenStreetMap contributors, ODbL.

Weather in Kumamoto by month

Average weather in Kumamoto over 2016–2025: the warmest month is August. Months that average 20 °C or more by day: April–October (20.6–32.3 °C). Months that average 30 °C or more by day: July (30.8 °C) and August (32.3 °C). No month averages below 0 °C at night; the coldest nights, in January, average 1.4 °C. About 2322 mm of rain falls in a year, on 160 days; June is the wettest month (442 mm) and December the driest (70 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).