While rain has a very slim chance of canceling a flight, there can be a minor chance that rain will delay it. Rain is just water, no matter the pressure. Modern aircraft can generate lift regardless of the heaviness of the rain. Planes can and will take off and land in the rain.

Standard rain generally does not affect a plane's ability to take off, as modern commercial aircraft are designed to operate safely in wet conditions. The engines are engineered to ingest massive amounts of water without flameout, and the tires are deeply grooved to prevent hydroplaning on the runway. However, heavy rain can indirectly cause delays through reduced visibility and "runway contamination." If the rain is so torrential that pilots cannot see the runway lights or if there is "standing water" that could affect braking distance, air traffic control may pause departures until conditions improve. More importantly, heavy rain is often associated with thunderstorms and wind shear, which are the true dangers; pilots will never take off into a cell with significant "microburst" activity. In 2026, sophisticated onboard "Vertical Profile" radar allows pilots to see exactly where the heaviest precipitation is located, allowing them to wait for a "gap" in the storm. So, while a steady drizzle won't stop your flight, a localized summer downpour might lead to a 20-minute wait on the taxiway for safety reasons.