Extreme heat from human-caused climate change could make flight delays more common. Here’s why

Extreme heat caused by human-induced climate change could increase the frequency of flight delays, according to experts. While heat waves are known to disrupt travel plans, thinner air during hot summer days poses a lesser-known challenge for aircraft. Airlines may need to lighten the load by removing passengers or cargo, or reduce fuel capacity to ensure safe takeoffs.

This issue is particularly relevant for airports at high elevations or with shorter runways, such as those in desert regions across the U.S. Southwest and Middle East. Human-caused climate change is expected to make these disruptions more common, with researchers predicting that some airports may see takeoff restrictions or weight limits for up to 30% of flights departing during peak heat hours by mid-century.

The FAA does not set a single maximum temperature for takeoff, but operating limits vary based on the aircraft's make and model, weight, and the airport's elevation. As temperatures continue to rise, the number of days with extreme heat at major airports is increasing. For example, Phoenix Sky Harbor International Airport now averages over three times as many days reaching 110 degrees Fahrenheit as it did in the mid-1900s, and Las Vegas has seen an average of about 18 days per year with temperatures at or above 110 F between 2020 and 2025.

Airlines have dealt with these issues for years, with some canceling flights during periods of extreme heat in the past. Ultimately, safety remains the top priority for airlines when making decisions about weight restrictions during hot weather conditions.