Flying Ant Day happens when conditions are perfect for a nuptial flight, so every ant colony in the area will swarm on the same day. A recent study found that Swarming is triggered by the weather that ants only flew on days when it was warm, not windy and conditions had improved compared to the previous day. This can result in thousands of ants taking to the sky and making a nuisance of themselves. Often, summer events like the Wimbledon tennis championship can be interrupted by swarms of ants that can cover miles.