Today’s map of the day shows the average heat wave days from May to September by county for year 2010. A heat wave is known as a prolonged period of abnormally hot weather. From the map we can see many southern, midwest and northeastern states had a higher average in heat wave days indicated by the darker shading. For instance, Louisiana is mostly shaded dark, indicating the vast majority of the counties had a high average of heat wave days ranging from 26.01 to 62.00 days. In contrast, many counties within the western state had a low average of heat wave days indicated by the yellow/yellow-orange shading.