The best time to visit Northern Vietnam (Hanoi) is Nov–Feb. Month by month, the verdicts rate Oct–Mar as comfortable on both daytime heat and rainfall — 6 months in all.
Cool dry winter, hot wet summer
| Month | High °C | High °F | Rainy days | Verdict |
|---|---|---|---|---|
| January | 21.2 | 70 | 14% | Go |
| February | 24.2 | 76 | 20% | Go |
| March | 27.9 | 82 | 32% | Go |
| April | 31.5 | 89 | 38% | Fair |
| May | 32.4 | 90 | 58% | Too wet |
| June | 32.3 | 90 | 69% | Too wet |
| July | 32.0 | 90 | 73% | Too wet |
| August | 31.3 | 88 | 74% | Too wet |
| September | 30.4 | 87 | 58% | Too wet |
| October | 28.0 | 82 | 37% | Go |
| November | 25.1 | 77 | 21% | Go |
| December | 21.5 | 71 | 13% | Go |
Verdict combines mean daytime high with rainy-day frequency. “Rainy days” is the share of days in the month with at least 1 mm of rain.
December is the driest month, with rain on 13% of days and daytime highs near 21.5°C (71°F). August is the wettest, at 74%. The warmest month is May at 32.4°C (90°F); the coolest is January at 21.2°C (70°F). The record rules out too wet in May–Sep.