| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 4.1° | -3.4° | 36.7mm | 11.4 | 18 |
| February | 7.7° | -1.8° | 26.3mm | 8.9 | 37 |
| March | 12.9° | 1.4° | 35.9mm | 10.5 | 55 |
| April | 16.7° | 3.9° | 30.9mm | 8.9 | 72 |
| May | 22.2° | 8.4° | 39mm | 8.7 | 83 |
| June | 27.8° | 12.5° | 17.4mm | 5.1 | 87 |
| July | 34.4° | 17.2° | 5.3mm | 2.2 | 66 |
| August | 32.8° | 16.4° | 6.7mm | 2.3 | 72 |
| September | 26.9° | 11.6° | 11.3mm | 4.1 | 92 |
| October | 18.4° | 5.4° | 21.7mm | 6.2 | 82 |
| November | 9.8° | 0.2° | 30.6mm | 9.5 | 46 |
| December | 3.9° | -3.5° | 42.2mm | 12.6 | 15 |
January in Nampa averages a daily high of 4.1°C with nights around -3.4°C. Expect roughly 11.4 wet days totalling 36.7mm. A hard month to visit for comfort alone.
February in Nampa averages a daily high of 7.7°C with nights around -1.8°C. Expect roughly 8.9 wet days totalling 26.3mm. Demanding conditions — pack for it and plan indoor options.
March in Nampa averages a daily high of 12.9°C with nights around 1.4°C. Expect roughly 10.5 wet days totalling 35.9mm. Generally workable, with some weather to plan around.
April in Nampa averages a daily high of 16.7°C with nights around 3.9°C. Expect roughly 8.9 wet days totalling 30.9mm. Generally workable, with some weather to plan around.
May in Nampa averages a daily high of 22.2°C with nights around 8.4°C. Expect roughly 8.7 wet days totalling 39mm. Comfortable conditions for being outdoors all day.
June in Nampa averages a daily high of 27.8°C with nights around 12.5°C. Expect roughly 5.1 wet days totalling 17.4mm. Comfortable conditions for being outdoors all day.
July in Nampa averages a daily high of 34.4°C with nights around 17.2°C. Rain is rare — about 2.2 wet days and 5.3mm across the month. Generally workable, with some weather to plan around.
August in Nampa averages a daily high of 32.8°C with nights around 16.4°C. Rain is rare — about 2.3 wet days and 6.7mm across the month. Generally workable, with some weather to plan around.
September in Nampa averages a daily high of 26.9°C with nights around 11.6°C. Expect roughly 4.1 wet days totalling 11.3mm. Comfortable conditions for being outdoors all day.
October in Nampa averages a daily high of 18.4°C with nights around 5.4°C. Expect roughly 6.2 wet days totalling 21.7mm. Comfortable conditions for being outdoors all day.
November in Nampa averages a daily high of 9.8°C with nights around 0.2°C. Expect roughly 9.5 wet days totalling 30.6mm. Demanding conditions — pack for it and plan indoor options.
December in Nampa averages a daily high of 3.9°C with nights around -3.5°C. Expect roughly 12.6 wet days totalling 42.2mm. 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. Nampa peaks at 92.
Based on 30 years of records, June scores highest for comfort in Nampa, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 34.4°C.
December is the wettest, averaging 42.2mm of rain across roughly 12.6 wet days.
December is the coolest month, with average daily highs around 3.9°C.