Computer models predict a continuation of the persistent upper air pattern that has steered cool Canadian air into the Midwest. Monday southwest winds will briefly boost temperatures into the mid 80s over northern Illinois ahead of an approaching cold front. However this warming will be short-lived, as the cold front sinks into southern Illinois and cooler air returns after another bout of showers and thunderstorms Tuesday. The remainder of the week there will be only minor day to day variations in temperatures with highs averaging about 3 degrees below the seasonal norms.
Potential for Chicago's coldest July since 1891
As of July 25th this July's official Chicago temperatures have averaged 4.4 degrees below normal. If readings for the month end up averaging 4 degrees below normal, this July will be the sixth coldest on record dating back to 1871 and the coldest since 1891. All five of the coldest July's occurred prior to the 20th century when official observations for the city were taken at various locations downtown near Lake Michigan.
