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| Month | Prec. | Temp. |
| Jan | 2.1 in | 29.8 °F |
| Feb | 2 in | 33.8 °F |
| Mar | 3.3 in | 43.5°F |
| Apr | 4 in | 54.6°F |
| May | 4.8 in | 64.2°F |
| Jun | 4.65 in | 73°F |
| Jul | 3.8 in | 77.6°F |
| Aug | 3.7 in | 76 °F |
| Sep | 4 in | 68.3 °F |
| Oct | 3.2 in | 57.1 °F |
| Nov | 2.9 in | 44°F |
| Dec | 2.4 in | 33.3°F |
The table to the right shows the monthly mean temperature and precipitations from 1895-2003.
While the table would suggest a very mild climate one has to consider that temperature fluctuations of 30-40 degrees F in a twenty four hour period is considered normal. The mean temperature should not be used in discussions regarding the climate of Missouri. Although the mean temperature for June and July is only 73 and 76 degrees F it is not uncommon for the temperature to reach 100 degrees F at least 3 concurrent days each week in these months, as it did in 1904 during the World Fair where the temperature in Saint Louis was 103 degrees F.
Winters, December through February, are typically cold though without much snow as there is often little percepitation during the winter months. The months Dec-Feb receive the least amount of rain by far than any other season. Although the winter does not produce a lot of precipitation it is not uncommon to receive 1 to 2 inches of snow each week during the winter months from January to March. The mean temperature for these months from 1895 until 2003 has been approximately 0°C or (32°F) and the mean percipitation for those years has been 16.5 cm (6.5 inches). January typically has the coldest mean temperatures though not necessarily the extreme lows for the year. Temperatures for this season have been slowly rising from 1895 about 0.11°F per decade.
Spring, March through May, is generally the wettest season of the year with the mean temperature from 1895 until 2003 being about 12°C (54°F) and its mean percipitation for this period being approximately 30.5 cm (12 inches). The Spring rains often continue through June. The spring also produces the most tornados with an average of 90 tornados each year.
Summer, June through August, is the hottest time of the year with a mean temperature of 24°C (75°F) and a mean precipitation of 30.5 cm (12 inches) with June having more precipitation than either July or August. The extreme highs for the year often occur in July or August.
Fall, September through November, has less and less precipitation towards the end of the season. The mean temperatures for this season are 13.6°C (56.5°F) and the mean percipitation is 25.4 cm (10 in).