Partly sunny skies and a high temperature of 81 are expected Thursday.
But, after several days of warmer than usual temperatures and more than three weeks without rain, the weather will change significantly by the weekend.
Clouds will move in Thursday night when the low will drop to 57, according to the National Weather Service.
There is a 60 percent chance of showers in the forecast during the day Friday when the high will be 75 and into the evening then the low will be 61.
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On Saturday, there is a 50 percent chance of rain during the day when the high will be 70. During the evening, the chance of rain will drop to 20 percent while the temperature will drop to 48.
Sunny skies will return Sunday. But the cooling trend will continue with the high reaching only 66.
It’s not unusual for the temperature to drop quickly at this time of year. The average high in the St. Louis area for Oct. 1 is 76, by Oct. 10 it falls to 72, by Oct. 20 its 68 and by Oct. 31 it’s 62.