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St. Charles County, MO Climate
1991 to 2020 normals at Weldon Spring NWS, 4.3 mi from the center of St. Charles County, elevation 610 ft.
Average weather by month
Select a month for daily normals and last year's weather
| Month | Range | High | Low | Precip. | Snow |
|---|---|---|---|---|---|
| January | 39° | 21° | 2.61 in | 4.1 in | |
| February | 45° | 24° | 2.43 in | 3.7 in | |
| March | 55° | 33° | 3.74 in | 1.7 in | |
| April | 67° | 44° | 4.70 in | 0.2 in | |
| May | 76° | 54° | 5.09 in | 0.0 in | |
| June | 84° | 63° | 4.72 in | 0.0 in | |
| July | 88° | 67° | 3.92 in | 0.0 in | |
| August | 87° | 65° | 3.58 in | 0.0 in | |
| September | 80° | 57° | 3.50 in | 0.0 in | |
| October | 68° | 46° | 3.37 in | 0.0 in | |
| November | 55° | 35° | 3.69 in | 0.8 in | |
| December | 44° | 26° | 3.07 in | 3.0 in | |
| Year | 66° | 44.42 in | 13.5 in |
Frequently asked questions
- What is the hottest month in St. Charles County, MO?
- July is the warmest month, with a normal high of 88°F at Weldon Spring NWS.
- What is the coldest month in St. Charles County, MO?
- January is the coldest month, with a normal low of 21°F.
- What is the wettest month in St. Charles County, MO?
- May has the most precipitation on average, about 5.09 inches.