| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | -0.4° | -9° | 29.8mm | 11.2 | 8 |
| February | 2.3° | -7.6° | 23.2mm | 8.7 | 13 |
| March | 9.3° | -2.7° | 31.9mm | 9.5 | 40 |
| April | 14.5° | 0.6° | 33.7mm | 9.5 | 61 |
| May | 19.6° | 5.1° | 46.8mm | 9.7 | 79 |
| June | 25.5° | 9.2° | 25.6mm | 6 | 88 |
| July | 30.9° | 12.9° | 11.6mm | 3.8 | 77 |
| August | 30° | 11.8° | 17mm | 4.9 | 78 |
| September | 24.4° | 7.3° | 29.4mm | 5.3 | 89 |
| October | 16° | 1.4° | 29.4mm | 6.8 | 73 |
| November | 7° | -3.9° | 24mm | 7.8 | 34 |
| December | 0° | -8.5° | 28.8mm | 10.3 | 9 |
January in Idaho Falls averages a daily high of -0.4°C with nights around -9°C. Expect roughly 11.2 wet days totalling 29.8mm. A hard month to visit for comfort alone.
February in Idaho Falls averages a daily high of 2.3°C with nights around -7.6°C. Expect roughly 8.7 wet days totalling 23.2mm. A hard month to visit for comfort alone.
March in Idaho Falls averages a daily high of 9.3°C with nights around -2.7°C. Expect roughly 9.5 wet days totalling 31.9mm. Demanding conditions — pack for it and plan indoor options.
April in Idaho Falls averages a daily high of 14.5°C with nights around 0.6°C. Expect roughly 9.5 wet days totalling 33.7mm. Generally workable, with some weather to plan around.
May in Idaho Falls averages a daily high of 19.6°C with nights around 5.1°C. Expect roughly 9.7 wet days totalling 46.8mm. Comfortable conditions for being outdoors all day.
June in Idaho Falls averages a daily high of 25.5°C with nights around 9.2°C. Expect roughly 6 wet days totalling 25.6mm. Comfortable conditions for being outdoors all day.
July in Idaho Falls averages a daily high of 30.9°C with nights around 12.9°C. Expect roughly 3.8 wet days totalling 11.6mm. Comfortable conditions for being outdoors all day.
August in Idaho Falls averages a daily high of 30°C with nights around 11.8°C. Expect roughly 4.9 wet days totalling 17mm. Comfortable conditions for being outdoors all day.
September in Idaho Falls averages a daily high of 24.4°C with nights around 7.3°C. Expect roughly 5.3 wet days totalling 29.4mm. Comfortable conditions for being outdoors all day.
October in Idaho Falls averages a daily high of 16°C with nights around 1.4°C. Expect roughly 6.8 wet days totalling 29.4mm. Generally workable, with some weather to plan around.
November in Idaho Falls averages a daily high of 7°C with nights around -3.9°C. Expect roughly 7.8 wet days totalling 24mm. A hard month to visit for comfort alone.
December in Idaho Falls averages a daily high of 0°C with nights around -8.5°C. Expect roughly 10.3 wet days totalling 28.8mm. 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. Idaho Falls peaks at 89.
Based on 30 years of records, June scores highest for comfort in Idaho Falls, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 30.9°C.
May is the wettest, averaging 46.8mm of rain across roughly 9.7 wet days.
January is the coolest month, with average daily highs around -0.4°C.