| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 2.2° | -9.2° | 15.9mm | 5.6 | 19 |
| February | 4.5° | -7.7° | 17.6mm | 5.2 | 25 |
| March | 11.3° | -2.2° | 41.1mm | 7 | 52 |
| April | 17.3° | 3.2° | 63mm | 8.6 | 74 |
| May | 22.8° | 9.9° | 120.6mm | 11.7 | 77 |
| June | 29.2° | 15.9° | 93.3mm | 9.7 | 72 |
| July | 31.2° | 18.6° | 79.6mm | 8.4 | 66 |
| August | 29.9° | 17.3° | 77.6mm | 8.5 | 71 |
| September | 26.5° | 12.1° | 50.8mm | 6.6 | 87 |
| October | 18.8° | 4.5° | 46.6mm | 6.2 | 84 |
| November | 11.1° | -2.3° | 27.2mm | 4.5 | 56 |
| December | 3.9° | -7.7° | 19.9mm | 5.2 | 24 |
January in Grand Island averages a daily high of 2.2°C with nights around -9.2°C. Expect roughly 5.6 wet days totalling 15.9mm. A hard month to visit for comfort alone.
February in Grand Island averages a daily high of 4.5°C with nights around -7.7°C. Expect roughly 5.2 wet days totalling 17.6mm. A hard month to visit for comfort alone.
March in Grand Island averages a daily high of 11.3°C with nights around -2.2°C. Expect roughly 7 wet days totalling 41.1mm. Demanding conditions — pack for it and plan indoor options.
April in Grand Island averages a daily high of 17.3°C with nights around 3.2°C. Expect roughly 8.6 wet days totalling 63mm. Generally workable, with some weather to plan around.
May in Grand Island averages a daily high of 22.8°C with nights around 9.9°C. Expect roughly 11.7 wet days totalling 120.6mm. Comfortable conditions for being outdoors all day.
June in Grand Island averages a daily high of 29.2°C with nights around 15.9°C. Expect roughly 9.7 wet days totalling 93.3mm. Generally workable, with some weather to plan around.
July in Grand Island averages a daily high of 31.2°C with nights around 18.6°C. Expect roughly 8.4 wet days totalling 79.6mm. Generally workable, with some weather to plan around.
August in Grand Island averages a daily high of 29.9°C with nights around 17.3°C. Expect roughly 8.5 wet days totalling 77.6mm. Generally workable, with some weather to plan around.
September in Grand Island averages a daily high of 26.5°C with nights around 12.1°C. Expect roughly 6.6 wet days totalling 50.8mm. Comfortable conditions for being outdoors all day.
October in Grand Island averages a daily high of 18.8°C with nights around 4.5°C. Expect roughly 6.2 wet days totalling 46.6mm. Comfortable conditions for being outdoors all day.
November in Grand Island averages a daily high of 11.1°C with nights around -2.3°C. Expect roughly 4.5 wet days totalling 27.2mm. Generally workable, with some weather to plan around.
December in Grand Island averages a daily high of 3.9°C with nights around -7.7°C. Expect roughly 5.2 wet days totalling 19.9mm. A hard month to visit for comfort alone.
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. Grand Island peaks at 87.
Based on 30 years of records, September–October scores highest for comfort in Grand Island, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 31.2°C.
May is the wettest, averaging 120.6mm of rain across roughly 11.7 wet days.
January is the coolest month, with average daily highs around 2.2°C.