There is a 30 percent chance of thunderstorms Monday with an expected high of 83.
After that, things will change drastically, according to the National Weather Service.
The high Tuesday will be 68 and on Wednesday it will reach 60. The average high temperature for mid-May in the St. Louis area is 77.
The best chance for rain Monday is between 1 and 4 p.m. Otherwise, skies will be mostly sunny.
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Monday night, the low will be 51 under mostly clear skies.
Despite the cooler temperatures, skies will be sunny Tuesday. The low will be 51 Tuesday night under partly cloudy skies.
There is a 60 percent chance of showers Wednesday. The chance of rain decreases to 30 percent in the evening with a low of 49.
The high temperature will rebound to 66 Thursday, 72 Friday and 75 Saturday.