Frost dates for Yokohama, Japan
Half of years have their last spring frost by March 21, but 1 year in 10 still frosts after March 31.
A frost date is really a percentile, here from 30 years (1991 to 2020) of a weather model’s daily lows near Yokohama: in about half of years a frost still comes after the median date. Both numbers are below, so you can choose the risk yourself.
The odds
Last spring frost
How often a frost still comes on or after each date.
- 1 year in 10
- March 31
- 1 year in 5
- March 28
- 3 years in 10
- March 26
- 2 years in 5
- March 22
- Half of years (the median)
- March 21
First fall freeze
How often the first freeze comes on or before each date.
- 1 year in 10
- December 5
- 1 year in 5
- December 8
- 3 years in 10
- December 10
- 2 years in 5
- December 12
- Half of years (the median)
- December 13
- Growing season
- about 269 days
- Hardiness zone nearby
- 9a, estimated from the weather model
Where these numbers come from
Modeled, not measured. No weather station stands behind these dates. They come from ERA5, a reconstruction of the world’s weather from 1991 to 2020 made by ECMWF, Europe’s medium-range weather forecasting agency, for the EU’s Copernicus program, and read here through Open-Meteo. They are the model’s daily lows for the point at 35.75, 139.75, 38 km (24 miles) from the center of Yokohama. A frost here means a low at or below 0 °C (32 °F).
The model’s point for Yokohama itself lies over the sea, where the water keeps the nights milder than on land, so these dates come from the nearest point over land, the one beside it.
A weather model sees the land in squares about 25 km (16 miles) across, so it can miss what sets one garden apart from the next: a frost hollow, a hillside, a lakeshore, a city’s own warmth. The Milpa planner reads these same numbers for a garden here and grades them A good hunch.
Cold air also pools in low ground on the clear, still nights when frost happens, so a hollow can freeze while a slope a few hundred feet away does not. No table can know that about your garden. Your own logged frosts eventually can.
Weather data by Open-Meteo.com, under CC BY 4.0. Contains modified Copernicus Climate Change Service information, 2026.
What can I plant here, and when? ›
Nearby cities
The nearest cities with a frost page here, and how their last-frost dates compare.
- Kawasaki, Japan, last frost by March 21
- Tokyo, Japan, last frost by March 21
- Nagoya, Japan, last frost by March 27
- Kyoto, Japan, last frost by April 4
- Osaka, Japan, last frost by March 17
- Kōbe, Japan, last frost by March 17
Other cities in Japan.
- Hiroshima, Japan, frost is rare
- Fukuoka, Japan, last frost by March 5
- Sapporo, Japan, last frost by April 26