WEATHER · CLIMATE NORMALS · 1991–2020
Hanoi Climate — Averages by Month
What the weather in Hanoi, VNaverages 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 | 16.9 °C · coldest | 48.1 mm |
| February | 18.5 °C | 35.3 mm |
| March | 21.1 °C | 61.7 mm |
| April | 25.0 °C | 110.7 mm |
| May | 28.0 °C | 233.7 mm |
| June | 29.8 °C · warmest | 231.8 mm |
| July | 29.5 °C | 267.1 mm |
| August | 28.8 °C | 320.2 mm · wettest |
| September | 27.7 °C | 230.7 mm |
| October | 25.4 °C | 127.3 mm |
| November | 22.0 °C | 59.7 mm |
| December | 18.1 °C | 37.9 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 Hanoi — centred at 21.00°N, 105.75°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.