Accurately monitoring the temperature outdoors isn’t easy. That’s because air temperatures are influenced by virtually anything heated by sunlight, and by engines and other equipment that generate heat.
Bubbles of warmth are known as heat islands. They make major contributions to the temperature in and around towns and cities, which are usually warmer than the countryside. The National Weather Service has developed guidelines for placing weather instruments to avoid heat islands (see www.srh.noaa.gov/epz/?n=cwopepz). But with the passage of time, fewer weather stations meet the guidelines, often because of the arrival of new buildings, sidewalks, and paved roads.
Stand-alone temperature ...