WEATHER · CLIMATE NORMALS · 1991–2020
Tokyo Climate — Averages by Month
What the weather in Tokyo, JPaverages across a standard 30-year period. Each month's figure is the 1991–2020 mean temperature and total rainfall from the ERA5 reanalysis — the long-run normal a place settles around, not a forecast for any particular day.
Month-by-month normals
| Month | Avg temperature | Avg rainfall |
|---|---|---|
| January | 4.8 °C · coldest | 70.2 mm |
| February | 5.7 °C | 68.8 mm |
| March | 9.1 °C | 113.3 mm |
| April | 14.2 °C | 116.4 mm |
| May | 18.9 °C | 133.4 mm |
| June | 22.2 °C | 165.8 mm |
| July | 25.9 °C | 152.3 mm |
| August | 27.3 °C · warmest | 117.7 mm |
| September | 23.7 °C | 189.6 mm |
| October | 18.2 °C | 210.3 mm · wettest |
| November | 12.6 °C | 92.9 mm |
| December | 7.4 °C | 60.6 mm |
How to read these numbers
These are reanalysis normals, not readings from a single weather station. They come from the ERA5 0.25° (~25 km) global reanalysis grid, sampled at the grid cell nearest Tokyo — centred at 35.75°N, 139.75°E. A reanalysis blends observations with a physics model onto an even grid, so a coastal or mountain city's cell can read a little cooler, warmer, wetter or drier than the city centre itself. The month-to-month shape — when it's hot, when it rains — is what these normals capture best.
“Normal” means the 1991–2020 average, the current World Meteorological Organization standard period. A normal is what a place tends toward over decades — any single day, month or year can and will depart from it.