| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 19.9° | — | 35.2mm | 8 | 84 |
| February | 20.8° | 15° | 26.8mm | 9.3 | 81 |
| March | 23° | — | 53mm | 14.4 | 71 |
| April | 27.2° | 21.8° | 66.5mm | 10.2 | 79 |
| May | 30.6° | 25.5° | 176mm | 11.1 | 63 |
| June | 32.4° | 26.5° | 198.8mm | 11.1 | 56 |
| July | 32.2° | 25.8° | 250.2mm | 14.2 | 51 |
| August | 31.7° | — | 364.1mm | 16.7 | 51 |
| September | 31.1° | — | 240.3mm | 13.1 | 57 |
| October | 29.7° | — | 87.5mm | 7.4 | 74 |
| November | 26.4° | 19.6° | 44.6mm | 5.7 | 89 |
| December | 22.2° | 15° | 24.6mm | 5 | 90 |
January in Hạ Long averages a daily high of 19.9°C. Expect roughly 8 wet days totalling 35.2mm. Comfortable conditions for being outdoors all day.
February in Hạ Long averages a daily high of 20.8°C with nights around 15°C. Expect roughly 9.3 wet days totalling 26.8mm. Comfortable conditions for being outdoors all day.
March in Hạ Long averages a daily high of 23°C. Expect roughly 14.4 wet days totalling 53mm. Generally workable, with some weather to plan around.
April in Hạ Long averages a daily high of 27.2°C with nights around 21.8°C. Expect roughly 10.2 wet days totalling 66.5mm. Comfortable conditions for being outdoors all day.
May in Hạ Long averages a daily high of 30.6°C with nights around 25.5°C. Expect roughly 11.1 wet days totalling 176mm. Generally workable, with some weather to plan around.
June in Hạ Long averages a daily high of 32.4°C with nights around 26.5°C. Expect roughly 11.1 wet days totalling 198.8mm. Generally workable, with some weather to plan around.
July in Hạ Long averages a daily high of 32.2°C with nights around 25.8°C. Expect roughly 14.2 wet days totalling 250.2mm. Demanding conditions — pack for it and plan indoor options.
August in Hạ Long averages a daily high of 31.7°C. Expect roughly 16.7 wet days totalling 364.1mm. Demanding conditions — pack for it and plan indoor options.
September in Hạ Long averages a daily high of 31.1°C. Expect roughly 13.1 wet days totalling 240.3mm. Generally workable, with some weather to plan around.
October in Hạ Long averages a daily high of 29.7°C. Expect roughly 7.4 wet days totalling 87.5mm. Generally workable, with some weather to plan around.
November in Hạ Long averages a daily high of 26.4°C with nights around 19.6°C. Expect roughly 5.7 wet days totalling 44.6mm. Comfortable conditions for being outdoors all day.
December in Hạ Long averages a daily high of 22.2°C with nights around 15°C. Expect roughly 5 wet days totalling 24.6mm. Comfortable conditions for being outdoors all day.
Each month scores out of 100. It starts at 100 and loses points for daytime highs outside a 20–27°C band, for wet days, and for nights below 2°C. Nothing else is weighted in — no crowd data, no prices, no opinion. Hạ Long peaks at 90.
Based on 30 years of records, November–January scores highest for comfort in Hạ Long, balancing daytime temperature against rainfall.
June is the warmest, averaging a daily high of 32.4°C.
August is the wettest, averaging 364.1mm of rain across roughly 16.7 wet days.
January is the coolest month, with average daily highs around 19.9°C.