Jet Contrails Can Affect Air Temperature in Some Areas, Study Shows

Jet contrails can mimic the weather impact of clouds and significantly affect daytime and nighttime air temperature swings — by up to 6 degrees Fahrenheit in some locales — researchers from Penn State have shown. Data from the three days following September 11, 2001, when air travel was highly restricted, had shown that jet contrails — thin clouds composed of ice crystals condensed from an aircraft’s exhaust — likely had an effect on air temperatures. To study the issue over a longer time period, the researchers looked at daily temperature data from locations in the South and Midwest that often see persistent jet contrails. They found that contrails, like clouds, depress the difference between daytime and nighttime temperatures, typically lowering daytime highs and raising nighttime lows. In the South, this amounted to a 6 degree F reduction in daily temperature range, and in the Midwest, roughly a 5 degree F reduction.