| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 0.5° | -10.9° | 6.3mm | 4 | 22 |
| February | 1.8° | -10.3° | 4.6mm | 2.8 | 24 |
| March | 6° | -6.4° | 9.2mm | 5 | 33 |
| April | 12.3° | -0.8° | 16.1mm | 5.7 | 60 |
| May | 18.2° | 4.8° | 50mm | 8.7 | 77 |
| June | 22.1° | 9.3° | 84.7mm | 11 | 78 |
| July | 26.9° | 11.7° | 32.6mm | 7.6 | 85 |
| August | 26.5° | 10.6° | 28.6mm | 6.6 | 87 |
| September | 21.1° | 6.5° | 29.4mm | 6.8 | 86 |
| October | 13.4° | 0.5° | 18.6mm | 5 | 67 |
| November | 5.9° | -5.5° | 7.1mm | 4.3 | 35 |
| December | 0.3° | -10.8° | 6.4mm | 4.3 | 21 |
January in Lethbridge averages a daily high of 0.5°C with nights around -10.9°C. Expect roughly 4 wet days totalling 6.3mm. A hard month to visit for comfort alone.
February in Lethbridge averages a daily high of 1.8°C with nights around -10.3°C. Rain is rare — about 2.8 wet days and 4.6mm across the month. A hard month to visit for comfort alone.
March in Lethbridge averages a daily high of 6°C with nights around -6.4°C. Expect roughly 5 wet days totalling 9.2mm. A hard month to visit for comfort alone.
April in Lethbridge averages a daily high of 12.3°C with nights around -0.8°C. Expect roughly 5.7 wet days totalling 16.1mm. Generally workable, with some weather to plan around.
May in Lethbridge averages a daily high of 18.2°C with nights around 4.8°C. Expect roughly 8.7 wet days totalling 50mm. Comfortable conditions for being outdoors all day.
June in Lethbridge averages a daily high of 22.1°C with nights around 9.3°C. Expect roughly 11 wet days totalling 84.7mm. Comfortable conditions for being outdoors all day.
July in Lethbridge averages a daily high of 26.9°C with nights around 11.7°C. Expect roughly 7.6 wet days totalling 32.6mm. Comfortable conditions for being outdoors all day.
August in Lethbridge averages a daily high of 26.5°C with nights around 10.6°C. Expect roughly 6.6 wet days totalling 28.6mm. Comfortable conditions for being outdoors all day.
September in Lethbridge averages a daily high of 21.1°C with nights around 6.5°C. Expect roughly 6.8 wet days totalling 29.4mm. Comfortable conditions for being outdoors all day.
October in Lethbridge averages a daily high of 13.4°C with nights around 0.5°C. Expect roughly 5 wet days totalling 18.6mm. Generally workable, with some weather to plan around.
November in Lethbridge averages a daily high of 5.9°C with nights around -5.5°C. Expect roughly 4.3 wet days totalling 7.1mm. Demanding conditions — pack for it and plan indoor options.
December in Lethbridge averages a daily high of 0.3°C with nights around -10.8°C. Expect roughly 4.3 wet days totalling 6.4mm. 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. Lethbridge peaks at 87.
Based on 30 years of records, July–September scores highest for comfort in Lethbridge, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 26.9°C.
June is the wettest, averaging 84.7mm of rain across roughly 11 wet days.
December is the coolest month, with average daily highs around 0.3°C.