The Urban Heat Island at Toledo, Ohio

Abstract

Thirty-one years of daily maximum and minimum temperatures at a rural site and a roof-top urban site were examined to determine the magnitude and seasonal variability of the urban heat island. Mean annual temperature was 2.0°C warmer at the urban site with the greatest urban-rural temperature difference occurring during the summer and the smallest difference during the spring. The urban heat island was more evident in daily minimum temperatures than in daily maxima. The number of days over 32°C (90°F) was more than doubled by the urban heat island and the number of freezing days was reduced by 16%. The freeze-free season was lengthened approximately 24 days by the urban warming, heating degree days were reduced by 10%, and cooling degree days were increased by 70%.