| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 5.8° | — | 167.8mm | 23 | 25 |
| February | 6.5° | — | 114.2mm | 18.5 | 27 |
| March | 10.2° | — | 102.8mm | 15.6 | 39 |
| April | 16.2° | — | 103.4mm | 13.7 | 60 |
| May | 21.9° | — | 101.2mm | 10.8 | 78 |
| June | 24.8° | — | 107.9mm | 10.5 | 79 |
| July | 28.9° | — | 250.1mm | 14.5 | 63 |
| August | 30.7° | — | 139.2mm | 10.4 | 64 |
| September | 26.6° | — | 154.1mm | 12.8 | 74 |
| October | 20.7° | — | 163.4mm | 14.9 | 70 |
| November | 14.6° | — | 192.5mm | 18.4 | 53 |
| December | 9° | — | 246.7mm | 23.6 | 35 |
January in Niigata averages a daily high of 5.8°C. Expect roughly 23 wet days totalling 167.8mm. A hard month to visit for comfort alone.
February in Niigata averages a daily high of 6.5°C. Expect roughly 18.5 wet days totalling 114.2mm. A hard month to visit for comfort alone.
March in Niigata averages a daily high of 10.2°C. Expect roughly 15.6 wet days totalling 102.8mm. Demanding conditions — pack for it and plan indoor options.
April in Niigata averages a daily high of 16.2°C. Expect roughly 13.7 wet days totalling 103.4mm. Generally workable, with some weather to plan around.
May in Niigata averages a daily high of 21.9°C. Expect roughly 10.8 wet days totalling 101.2mm. Comfortable conditions for being outdoors all day.
June in Niigata averages a daily high of 24.8°C. Expect roughly 10.5 wet days totalling 107.9mm. Comfortable conditions for being outdoors all day.
July in Niigata averages a daily high of 28.9°C. Expect roughly 14.5 wet days totalling 250.1mm. Generally workable, with some weather to plan around.
August in Niigata averages a daily high of 30.7°C. Expect roughly 10.4 wet days totalling 139.2mm. Generally workable, with some weather to plan around.
September in Niigata averages a daily high of 26.6°C. Expect roughly 12.8 wet days totalling 154.1mm. Generally workable, with some weather to plan around.
October in Niigata averages a daily high of 20.7°C. Expect roughly 14.9 wet days totalling 163.4mm. Generally workable, with some weather to plan around.
November in Niigata averages a daily high of 14.6°C. Expect roughly 18.4 wet days totalling 192.5mm. Demanding conditions — pack for it and plan indoor options.
December in Niigata averages a daily high of 9°C. Expect roughly 23.6 wet days totalling 246.7mm. Demanding conditions — pack for it and plan indoor options.
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. Niigata peaks at 79.
Based on 30 years of records, May–June scores highest for comfort in Niigata, balancing daytime temperature against rainfall.
August is the warmest, averaging a daily high of 30.7°C.
July is the wettest, averaging 250.1mm of rain across roughly 14.5 wet days.
January is the coolest month, with average daily highs around 5.8°C.