Heating during the day combined with moist air creates the cycle for cumulus clouds, some of which grow into thunderstorms. These can disrupt flights because flying through or landing in thunderstorms can be hazardous. ... The effect of thunderstorms in these spots can severely disrupt an airline's operation.

Can a plane take off in a thunderstorm?

Unlike strong winds, lightning doesn't really pose a problem for pilots, as planes have in-built protection against electricity and can fly unscathed through thunderstorms.

Is it safe to fly in stormy weather?

How safe is flying through a storm? ... For this reason, flying through a storm is generally safe. In the case of extreme weather, air traffic controllers will always direct aircraft above or around severe storms to avoid uncomfortable turbulence or any damage being done to the aircraft.