Let’s talk about minimum temperatures. The city of Houston has now recorded five consecutive mornings of 80-degree plus temperatures. This average of 81.6 degrees trails only a five-day period in 2011 (81.8 degrees) for the warmest stretch of minimum temperatures in about 120 years of records for the city of Houston.
Looking across the entire globe, climate scientists have been noticing this trend for some time—that as the planet warms nighttime temperatures appear to be warming faster than daytime temperatures. In Chapter 2 of the latest report from the Intergovernmental Panel on Climate Change, the authors write, “Confidence of accelerated increases in minimum temperature extremes compared to maximum temperature extremes is high due to the more consistent patterns of warming in minimum temperature extremes globally.”
Why is this happening?
Now there’s no question that development around northern Houston has played some role in warmer temperatures around the National Weather Service’s official station at Bush Intercontinental Airport. This is the so-called Urban Heat Island effect. However it would be wrong to attribute the nighttime warming to urbanization alone, as the global trends are pretty clear. Warmer nights locally are consistent with a warmer world.
