| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | -2.4° | -11.3° | 32.9mm | 7.6 | 15 |
| February | 0.1° | -10.1° | 37.2mm | 7.4 | 15 |
| March | 7.2° | -2.9° | 52.4mm | 9 | 34 |
| April | 14.7° | 3.6° | 94.3mm | 11.3 | 60 |
| May | 21.6° | 10.1° | 114.5mm | 12.8 | 74 |
| June | 27.4° | 16° | 134.3mm | 12 | 74 |
| July | 29.3° | 18.4° | 129.1mm | 8.8 | 73 |
| August | 28.1° | 17.6° | 90.3mm | 8.9 | 78 |
| September | 24.3° | 13° | 89.1mm | 8 | 84 |
| October | 16.6° | 6.1° | 81.8mm | 9.2 | 71 |
| November | 8° | -0.8° | 53.8mm | 7.3 | 43 |
| December | 0.7° | -7.4° | 44.1mm | 8.8 | 13 |
January in Dubuque averages a daily high of -2.4°C with nights around -11.3°C. Expect roughly 7.6 wet days totalling 32.9mm. A hard month to visit for comfort alone.
February in Dubuque averages a daily high of 0.1°C with nights around -10.1°C. Expect roughly 7.4 wet days totalling 37.2mm. A hard month to visit for comfort alone.
March in Dubuque averages a daily high of 7.2°C with nights around -2.9°C. Expect roughly 9 wet days totalling 52.4mm. A hard month to visit for comfort alone.
April in Dubuque averages a daily high of 14.7°C with nights around 3.6°C. Expect roughly 11.3 wet days totalling 94.3mm. Generally workable, with some weather to plan around.
May in Dubuque averages a daily high of 21.6°C with nights around 10.1°C. Expect roughly 12.8 wet days totalling 114.5mm. Generally workable, with some weather to plan around.
June in Dubuque averages a daily high of 27.4°C with nights around 16°C. Expect roughly 12 wet days totalling 134.3mm. Generally workable, with some weather to plan around.
July in Dubuque averages a daily high of 29.3°C with nights around 18.4°C. Expect roughly 8.8 wet days totalling 129.1mm. Generally workable, with some weather to plan around.
August in Dubuque averages a daily high of 28.1°C with nights around 17.6°C. Expect roughly 8.9 wet days totalling 90.3mm. Comfortable conditions for being outdoors all day.
September in Dubuque averages a daily high of 24.3°C with nights around 13°C. Expect roughly 8 wet days totalling 89.1mm. Comfortable conditions for being outdoors all day.
October in Dubuque averages a daily high of 16.6°C with nights around 6.1°C. Expect roughly 9.2 wet days totalling 81.8mm. Generally workable, with some weather to plan around.
November in Dubuque averages a daily high of 8°C with nights around -0.8°C. Expect roughly 7.3 wet days totalling 53.8mm. Demanding conditions — pack for it and plan indoor options.
December in Dubuque averages a daily high of 0.7°C with nights around -7.4°C. Expect roughly 8.8 wet days totalling 44.1mm. 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. Dubuque peaks at 84.
Based on 30 years of records, August–September scores highest for comfort in Dubuque, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 29.3°C.
June is the wettest, averaging 134.3mm of rain across roughly 12 wet days.
January is the coolest month, with average daily highs around -2.4°C.