| Month | High | Low | Rain | Wet days | Score |
|---|---|---|---|---|---|
| January | 4.7° | -4.1° | 70.6mm | 8.2 | 25 |
| February | 7.7° | -2.1° | 56.8mm | 7.4 | 40 |
| March | 13.6° | 3.4° | 97.2mm | 9.9 | 60 |
| April | 20° | 9.2° | 113.2mm | 10.6 | 79 |
| May | 25.2° | 15.1° | 125.6mm | 11.8 | 76 |
| June | 30° | 19.9° | 122.3mm | 9.5 | 69 |
| July | 31.9° | 21.8° | 124mm | 7.8 | 65 |
| August | 31.4° | 21.1° | 96.2mm | 7.4 | 68 |
| September | 27.4° | 16.4° | 85.5mm | 7.1 | 84 |
| October | 20.8° | 10° | 81mm | 8.5 | 83 |
| November | 13.7° | 4.1° | 88mm | 7.6 | 65 |
| December | 7.2° | -1.1° | 63.3mm | 8.4 | 38 |
January in St. Louis averages a daily high of 4.7°C with nights around -4.1°C. Expect roughly 8.2 wet days totalling 70.6mm. A hard month to visit for comfort alone.
February in St. Louis averages a daily high of 7.7°C with nights around -2.1°C. Expect roughly 7.4 wet days totalling 56.8mm. Demanding conditions — pack for it and plan indoor options.
March in St. Louis averages a daily high of 13.6°C with nights around 3.4°C. Expect roughly 9.9 wet days totalling 97.2mm. Generally workable, with some weather to plan around.
April in St. Louis averages a daily high of 20°C with nights around 9.2°C. Expect roughly 10.6 wet days totalling 113.2mm. Comfortable conditions for being outdoors all day.
May in St. Louis averages a daily high of 25.2°C with nights around 15.1°C. Expect roughly 11.8 wet days totalling 125.6mm. Comfortable conditions for being outdoors all day.
June in St. Louis averages a daily high of 30°C with nights around 19.9°C. Expect roughly 9.5 wet days totalling 122.3mm. Generally workable, with some weather to plan around.
July in St. Louis averages a daily high of 31.9°C with nights around 21.8°C. Expect roughly 7.8 wet days totalling 124mm. Generally workable, with some weather to plan around.
August in St. Louis averages a daily high of 31.4°C with nights around 21.1°C. Expect roughly 7.4 wet days totalling 96.2mm. Generally workable, with some weather to plan around.
September in St. Louis averages a daily high of 27.4°C with nights around 16.4°C. Expect roughly 7.1 wet days totalling 85.5mm. Comfortable conditions for being outdoors all day.
October in St. Louis averages a daily high of 20.8°C with nights around 10°C. Expect roughly 8.5 wet days totalling 81mm. Comfortable conditions for being outdoors all day.
November in St. Louis averages a daily high of 13.7°C with nights around 4.1°C. Expect roughly 7.6 wet days totalling 88mm. Generally workable, with some weather to plan around.
December in St. Louis averages a daily high of 7.2°C with nights around -1.1°C. Expect roughly 8.4 wet days totalling 63.3mm. Demanding conditions — pack for it and plan indoor options.
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. St. Louis peaks at 84.
Based on 30 years of records, April–May scores highest for comfort in St. Louis, balancing daytime temperature against rainfall.
July is the warmest, averaging a daily high of 31.9°C.
May is the wettest, averaging 125.6mm of rain across roughly 11.8 wet days.
January is the coolest month, with average daily highs around 4.7°C.