| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 4.6° | -6.7° | 11.1mm | 4.5 | 29 |
| February | 8.5° | -3.8° | 12.2mm | 5.1 | 44 |
| March | 14.5° | 0.6° | 18mm | 5.6 | 69 |
| April | 18.9° | 4.4° | 23.2mm | 6.6 | 83 |
| May | 24.8° | 9.7° | 20.5mm | 4.7 | 91 |
| June | 31.4° | 15.2° | 13mm | 3.2 | 76 |
| July | 34.6° | 18.7° | 18.7mm | 4.9 | 60 |
| August | 32.6° | 17.3° | 22.5mm | 6.2 | 65 |
| September | 27.8° | 12.7° | 28.1mm | 6.5 | 84 |
| October | 19.8° | 5.2° | 24mm | 5.3 | 89 |
| November | 11.9° | -1.1° | 14.6mm | 4.2 | 61 |
| December | 4.7° | -6.5° | 12.7mm | 4.2 | 30 |
January in Grand Junction averages a daily high of 4.6°C with nights around -6.7°C. Expect roughly 4.5 wet days totalling 11.1mm. A hard month to visit for comfort alone.
February in Grand Junction averages a daily high of 8.5°C with nights around -3.8°C. Expect roughly 5.1 wet days totalling 12.2mm. Demanding conditions — pack for it and plan indoor options.
March in Grand Junction averages a daily high of 14.5°C with nights around 0.6°C. Expect roughly 5.6 wet days totalling 18mm. Generally workable, with some weather to plan around.
April in Grand Junction averages a daily high of 18.9°C with nights around 4.4°C. Expect roughly 6.6 wet days totalling 23.2mm. Comfortable conditions for being outdoors all day.
May in Grand Junction averages a daily high of 24.8°C with nights around 9.7°C. Expect roughly 4.7 wet days totalling 20.5mm. Comfortable conditions for being outdoors all day.
June in Grand Junction averages a daily high of 31.4°C with nights around 15.2°C. Expect roughly 3.2 wet days totalling 13mm. Comfortable conditions for being outdoors all day.
July in Grand Junction averages a daily high of 34.6°C with nights around 18.7°C. Expect roughly 4.9 wet days totalling 18.7mm. Generally workable, with some weather to plan around.
August in Grand Junction averages a daily high of 32.6°C with nights around 17.3°C. Expect roughly 6.2 wet days totalling 22.5mm. Generally workable, with some weather to plan around.
September in Grand Junction averages a daily high of 27.8°C with nights around 12.7°C. Expect roughly 6.5 wet days totalling 28.1mm. Comfortable conditions for being outdoors all day.
October in Grand Junction averages a daily high of 19.8°C with nights around 5.2°C. Expect roughly 5.3 wet days totalling 24mm. Comfortable conditions for being outdoors all day.
November in Grand Junction averages a daily high of 11.9°C with nights around -1.1°C. Expect roughly 4.2 wet days totalling 14.6mm. Generally workable, with some weather to plan around.
December in Grand Junction averages a daily high of 4.7°C with nights around -6.5°C. Expect roughly 4.2 wet days totalling 12.7mm. 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 Junction peaks at 91.
Based on 30 years of records, April–May scores highest for comfort in Grand Junction, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 34.6°C.
September is the wettest, averaging 28.1mm of rain across roughly 6.5 wet days.
January is the coolest month, with average daily highs around 4.6°C.