Last weekend provided a nice example of the conditions needed for an Urban Heat Island to develop. On a clear calm night (23/24 April 2015) temperatures at rural Sonning Common fell to 1⁰C, whereas the minimum 7km away in Reading city centre was 7⁰C, an urban heat island (UHI) effect of 6⁰C. The next night (24/25 April) was cloudy and windy; rural minimum temperatures were some 10 degC warmer than previous night, with a UHI effect of only about 1⁰C.

You can find some idea about how to use WOW data with a class to study local Urban Heat Islands here.