Based on the many emails received from our readers this week, there is apparent confusion in the interpretation of the seven daily forecast high and low temperatures on our Chicago Tribune weather page. The high and low temperature forecasts on this page are based on a chronological format and the premise that the weather on the first day begins when the reader opens the morning paper. The forecast high is the highest temperature expected to occur that day, which in most cases is in the afternoon. The forecast low in the lowest temperature expected to occur during the next overnight period and on the vast majority of days will occur around daybreak the following morning. For example, if the Wednesday forecast high/low temperature forecast is 15/-5, the 15 is expected Wednesday afternoon, but the low of -5 will not occur until Thursday morning. This chronological format is followed through the entire seven day forecast period on the Tribune weather page.
One reason for the apparent confusion may arise from the difference between the reporting of the high/low for forecast weather and past weather. When referring to the recorded high/low from a previous day, the high and low temperature values are the actual temperature extremes that were recorded during that 24-hour calendar day.
Hoping that this explanation will help eliminate the confusion.