Why do many termite colonies swarm at the same time?

Termite colonies often swarm simultaneously in a given area, a phenomenon that can even be synchronized across regions separated by hundreds of miles. This mass emergence of winged adults, known as alates, is primarily triggered by specific environmental conditions, including high atmospheric humidity combined with temperature and seasonal factors that vary by species.1

While the flight serves as a means of dispersal, the synchronization of these events across multiple colonies provides a significant biological advantage: it facilitates intercolony mating. By swarming at the same time, termites increase the likelihood of encountering mates from different colonies, which helps maintain genetic diversity during the mating flight.1