| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 10° | 3° | 91.8mm | 7.8 | 52 |
| February | 10.2° | 2.5° | 98.3mm | 9.6 | 49 |
| March | 12.3° | 6.4° | 135.2mm | 12.4 | 51 |
| April | 16.8° | 10.9° | 131.6mm | 12.1 | 66 |
| May | 20.8° | 14.9° | 147.5mm | 11.1 | 78 |
| June | 23.1° | 17.6° | 176.4mm | 12.3 | 75 |
| July | 27° | 21° | 141.9mm | 10.5 | 79 |
| August | 28.8° | 23.2° | 107.9mm | 7.7 | 77 |
| September | 26.1° | 21.3° | 209.3mm | 11.2 | 78 |
| October | 21.6° | 16.9° | 260.7mm | 13.3 | 73 |
| November | 17.3° | 10.9° | 135.3mm | 10.7 | 70 |
| December | 12.5° | 5.4° | 90.4mm | 8.1 | 60 |
January in Katori-shi averages a daily high of 10°C with nights around 3°C. Expect roughly 7.8 wet days totalling 91.8mm. Demanding conditions — pack for it and plan indoor options.
February in Katori-shi averages a daily high of 10.2°C with nights around 2.5°C. Expect roughly 9.6 wet days totalling 98.3mm. Demanding conditions — pack for it and plan indoor options.
March in Katori-shi averages a daily high of 12.3°C with nights around 6.4°C. Expect roughly 12.4 wet days totalling 135.2mm. Demanding conditions — pack for it and plan indoor options.
April in Katori-shi averages a daily high of 16.8°C with nights around 10.9°C. Expect roughly 12.1 wet days totalling 131.6mm. Generally workable, with some weather to plan around.
May in Katori-shi averages a daily high of 20.8°C with nights around 14.9°C. Expect roughly 11.1 wet days totalling 147.5mm. Comfortable conditions for being outdoors all day.
June in Katori-shi averages a daily high of 23.1°C with nights around 17.6°C. Expect roughly 12.3 wet days totalling 176.4mm. Comfortable conditions for being outdoors all day.
July in Katori-shi averages a daily high of 27°C with nights around 21°C. Expect roughly 10.5 wet days totalling 141.9mm. Comfortable conditions for being outdoors all day.
August in Katori-shi averages a daily high of 28.8°C with nights around 23.2°C. Expect roughly 7.7 wet days totalling 107.9mm. Comfortable conditions for being outdoors all day.
September in Katori-shi averages a daily high of 26.1°C with nights around 21.3°C. Expect roughly 11.2 wet days totalling 209.3mm. Comfortable conditions for being outdoors all day.
October in Katori-shi averages a daily high of 21.6°C with nights around 16.9°C. Expect roughly 13.3 wet days totalling 260.7mm. Generally workable, with some weather to plan around.
November in Katori-shi averages a daily high of 17.3°C with nights around 10.9°C. Expect roughly 10.7 wet days totalling 135.3mm. Generally workable, with some weather to plan around.
December in Katori-shi averages a daily high of 12.5°C with nights around 5.4°C. Expect roughly 8.1 wet days totalling 90.4mm. Generally workable, with some weather to plan around.
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. Katori-shi peaks at 79.
Based on 30 years of records, May–October scores highest for comfort in Katori-shi, balancing daytime temperature against rainfall.
August is the warmest, averaging a daily high of 28.8°C.
October is the wettest, averaging 260.7mm of rain across roughly 13.3 wet days.
January is the coolest month, with average daily highs around 10°C.