Wind speeds above roughly 30 to 40 mph (25 to 35 knots) commonly cause flight delays at major airports, though the exact threshold depends on whether the wind is blowing across the runway, from behind the aircraft, or shifting unpredictably. There is no single number that grounds all flights. Instead, delays build gradually as wind conditions approach the limits that pilots and air traffic controllers are allowed to work within.
Crosswind Limits for Commercial Aircraft
The wind direction relative to the runway matters more than raw speed. A 35 mph headwind (blowing straight down the runway toward an arriving plane) actually helps with landing, while that same 35 mph blowing sideways across the runway becomes a serious problem. This sideways component is called crosswind, and it is the main wind-related reason flights get delayed or diverted.
The most common narrow-body jets, the Boeing 737 and Airbus A320, both have a maximum demonstrated crosswind of 33 knots (about 38 mph). That means the manufacturer has proven the aircraft can land safely in crosswinds up to that speed. In practice, though, airlines often set their own limits lower than the manufacturer number, sometimes as low as 25 to 30 knots depending on the carrier, the specific aircraft variant, and the experience level required of the crew. So delays can start well before winds hit 38 mph.
Federal regulations set a default maximum crosswind of 20 knots (23 mph) for any aircraft that hasn’t been tested and approved at a higher value. Most modern airliners have demonstrated limits well above that baseline, but smaller regional jets and turboprops generally have lower crosswind tolerances than larger planes. A wide-body aircraft like a Boeing 747 handles crosswinds more comfortably than a small regional jet simply because of its greater mass and wingspan, which make it more resistant to being pushed off course.
Tailwind Limits Are Much Lower
Tailwinds, where the wind blows in the same direction the plane is traveling, are far more disruptive at lower speeds than crosswinds. The standard maximum tailwind for landing is just 10 knots (about 12 mph). Beyond that, the aircraft needs significantly more runway to stop because the wind effectively adds to its ground speed. Simulations of large aircraft show that a 25-foot-per-second tailwind (roughly 17 mph) during approach can cause an undershoot of approximately 4,000 feet from the intended touchdown point, a dangerous margin of error.
When tailwinds pick up, controllers will typically switch the active runway direction so planes land into the wind instead. But at busy airports, flipping runway operations takes time and reduces the number of planes that can land per hour, which is one of the less obvious ways wind causes delays even when no flights are technically cancelled.
Wind Shear and Gusts
Steady wind at any speed is easier to manage than wind that changes suddenly. Low-level wind shear, defined as a change of 10 knots or more per 100 feet of altitude in the lowest 2,000 feet above the ground, is one of the most dangerous weather conditions for landing aircraft. When sensors detect wind shear near the airport, controllers will slow or stop arrivals entirely until conditions improve.
Gusts matter too. A steady 25-knot crosswind is manageable for most airliners, but 25 knots gusting to 40 is a different situation. The aircraft has to be controllable at the peak gust speed, not just the average. Airbus, for example, lists its A320 crosswind limit with an additional note: gusting to 38 knots. If gusts exceed that number, the flight waits on the ground or diverts to another airport.
Microbursts, sudden columns of sinking air that spread outward on contact with the ground, combine rapid wind direction changes with strong downdrafts. An aircraft caught in a microburst during approach can be forced into a steep descent that overshoots or undershoots the runway by thousands of feet. Airports with microburst detection systems will issue warnings that effectively pause arrivals.
How Wet or Icy Runways Change the Math
Wind limits drop further when the runway surface is contaminated with water, snow, or ice. A plane landing in a crosswind needs to straighten out from a sideways angle right before touchdown, and that correction relies on tire grip. On a wet or icy runway, there is less grip available, so pilots and airlines reduce their acceptable crosswind limits accordingly. The FAA requires that operators adjust crosswind guidance for contaminated runway conditions, though specific numbers vary by airline and aircraft type. In winter storms, this means flights may be delayed at wind speeds that would be perfectly routine on a dry summer day.
Why Delays Start Before Limits Are Reached
You might check the weather and see winds of 25 knots, well below the 33-knot crosswind limit, and still find your flight delayed. Several factors explain this gap. First, air traffic control reduces the landing rate in strong winds because pilots need more spacing to deal with turbulence on approach. An airport that normally handles 60 arrivals per hour might drop to 40, and that bottleneck cascades through the schedule. Second, airlines build in safety margins below the hard limits, especially for newer pilots or when gusts are forecast to increase. Third, if the wind direction is between runways (not aligned with any of them), every runway has a crosswind component, and controllers may need to close some configurations entirely.
The practical answer for travelers: sustained winds above 20 to 25 knots (23 to 29 mph) at an airport start creating conditions where delays become likely. Above 30 knots (35 mph), delays are common. Above 40 knots (46 mph), widespread cancellations and diversions are typical, especially for smaller aircraft. Checking your airport’s real-time wind conditions alongside the runway layout gives you the best sense of whether your specific flight is at risk.