Hiroshima, Hiroshima, Japan
Planting calendar for Hiroshima
Worked out from 30 years of daily minimum temperatures for this location — not from a zone map, and not from the nearest big city. Move the dial to change how much frost risk you are willing to carry, and every date on the page re-times itself.
Last spring frost
6 April
Frost has finished by this date in 1 year in 2.
First autumn frost
29 November
Bring tender crops in before this date.
Frost-free season
238 days
Long season
The average last frost. Half of all years are later than this.
Sow this week in Hiroshima
Windows that are open today, 6 August. The ones marked in amber are closing within a fortnight.
Opening soon
Sow this week in Hiroshima
Windows that are open today, 6 August. The ones marked in amber are closing within a fortnight.
Opening soon
Sow this week in Hiroshima
Windows that are open today, 6 August. The ones marked in amber are closing within a fortnight.
Opening soon
The growing year in Hiroshima
307 crops, timed to the dates above
Each bar is a window, not a deadline. Tap or hover a bar for its dates, or follow a crop name for the full timing and a harvest estimate. The blue wash is the measured weekly chance of frost across the whole record. There is also a printable one-page version of this calendar for the shed wall.
The climate behind these dates
Mean monthly temperature across the record. Months shown in blue average at least one air frost.
Nearby
Frost dates close to Hiroshima
Similar climate
Places that garden like Hiroshima
Matched on frost dates and season length rather than on distance, which is often more useful: advice written for one of these places usually transfers.
Questions about frost in Hiroshima
When is the last frost in Hiroshima?
The median last spring frost in Hiroshima falls on 6 April. In one year in ten frost continues as late as 17 April, so if you cannot protect tender plants, 17 April is the safer date to work to.
When is the first frost in Hiroshima?
The median first autumn frost in Hiroshima falls on 29 November, though in one year in ten it arrives by 19 November. Tender crops should be harvested before that earlier date.
How long is the growing season in Hiroshima?
About 238 frost-free days on a median year - long by world standards. Taking the cautious view at both ends, plan for roughly 216 dependable days.
What hardiness zone is Hiroshima in?
Hiroshima sits in USDA-equivalent zone 9a, based on a mean annual extreme minimum of -5.4°C (22.4°F). Perennials rated to this zone or lower should survive an average winter here.
Can I trust these dates exactly?
They are statistics, not forecasts. They describe what happened across 30 years of records at this location and say nothing about this particular spring. Frost is also intensely local: a low-lying or exposed garden can run a week behind the figures on this page.