| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 18.6° | 11.6° | 45.7mm | 5.5 | 85 |
| February | 19.5° | 12.2° | 74.9mm | 9.4 | 80 |
| March | 21.6° | 14.9° | 68.6mm | 9 | 82 |
| April | 25.4° | 18.8° | 139.2mm | 10.4 | 79 |
| May | 28.5° | 22.5° | 214.5mm | 14.9 | 64 |
| June | 30.8° | 25.3° | 306.1mm | 17.8 | 55 |
| July | 32.6° | 26.2° | 211.1mm | 12.2 | 53 |
| August | 32.4° | 26° | 249.7mm | 14.3 | 50 |
| September | 31.3° | 24.7° | 155.1mm | 8.8 | 65 |
| October | 28.7° | 21.9° | 51.9mm | 4.6 | 84 |
| November | 25.1° | 17.4° | 49.3mm | 4.5 | 91 |
| December | 20.7° | 13° | 34mm | 5.7 | 89 |
January in Haimen averages a daily high of 18.6°C with nights around 11.6°C. Expect roughly 5.5 wet days totalling 45.7mm. Comfortable conditions for being outdoors all day.
February in Haimen averages a daily high of 19.5°C with nights around 12.2°C. Expect roughly 9.4 wet days totalling 74.9mm. Comfortable conditions for being outdoors all day.
March in Haimen averages a daily high of 21.6°C with nights around 14.9°C. Expect roughly 9 wet days totalling 68.6mm. Comfortable conditions for being outdoors all day.
April in Haimen averages a daily high of 25.4°C with nights around 18.8°C. Expect roughly 10.4 wet days totalling 139.2mm. Comfortable conditions for being outdoors all day.
May in Haimen averages a daily high of 28.5°C with nights around 22.5°C. Expect roughly 14.9 wet days totalling 214.5mm. Generally workable, with some weather to plan around.
June in Haimen averages a daily high of 30.8°C with nights around 25.3°C. Expect roughly 17.8 wet days totalling 306.1mm. Generally workable, with some weather to plan around.
July in Haimen averages a daily high of 32.6°C with nights around 26.2°C. Expect roughly 12.2 wet days totalling 211.1mm. Demanding conditions — pack for it and plan indoor options.
August in Haimen averages a daily high of 32.4°C with nights around 26°C. Expect roughly 14.3 wet days totalling 249.7mm. Demanding conditions — pack for it and plan indoor options.
September in Haimen averages a daily high of 31.3°C with nights around 24.7°C. Expect roughly 8.8 wet days totalling 155.1mm. Generally workable, with some weather to plan around.
October in Haimen averages a daily high of 28.7°C with nights around 21.9°C. Expect roughly 4.6 wet days totalling 51.9mm. Comfortable conditions for being outdoors all day.
November in Haimen averages a daily high of 25.1°C with nights around 17.4°C. Expect roughly 4.5 wet days totalling 49.3mm. Comfortable conditions for being outdoors all day.
December in Haimen averages a daily high of 20.7°C with nights around 13°C. Expect roughly 5.7 wet days totalling 34mm. 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. Haimen peaks at 91.
Based on 30 years of records, October–January scores highest for comfort in Haimen, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 32.6°C.
June is the wettest, averaging 306.1mm of rain across roughly 17.8 wet days.
January is the coolest month, with average daily highs around 18.6°C.