Why Is My Flight Delayed?

Weather events wreak havoc on travel plans

Wondering why your flight is delayed? Weather is likely to blame. It can be so unpredictable that some airlines have their own meteorology departments.

No one can control the weather, but it does help to understand how it impacts flight operations. Read on for a primer on how weather events can cause travel plans to go sideways.

Extreme Cold

When it’s so cold teardrops freeze on your face, there’s a chance you could be delayed. Extreme cold has the potential to cause issues with aircraft systems and fuel.

Just like starting a car in the cold, it can be challenging to start an aircraft’s engines after a night parked outdoors overnight. But this type of delay is quite rare, because cold doesn’t negatively impact an aircraft’s performance. Once the engines are started, you’re usually good to go. (Click here for more about how planes are tested in extreme temperatures.)

Feel the chill? Pictured here in 2014 is Boom Supersonic Chief Flight Test Engineer Jeff Mabry examining icing on the front of his helicopter from a 15-minute flight.

When it comes to big snowstorms, getting to the airport is just the beginning of a traveler’s challenges. Like roads, airport runways must be plowed, and it’s tough to keep up in a blizzard.

Active snowfall causes issues with takeoff and landing. Takeoffs will be delayed because everyone has to de-ice (see below) and each aircraft must wait its turn. When it comes to landing, heavy snow on a runway reduces the braking effectiveness of an aircraft. (Like a car without snow tires, an aircraft could slide.) That’s why properly clearing the runway is essential for safe landings.

De-Icing: If there is any kind of “contaminant” — such as snow, frost or ice — on an aircraft, it likely needs to be de-iced. There are many types of de-icing. The method depends on the conditions. Technicians may blow warm air or spray de-icing fluid onto the aircraft, like a shower. De-icing adds an extra step to the journey, which can cause delays. (On some routes, de-icing is required so often that extra time is built into the total flight time. The journey takes long, but you won’t experience a delay.)

Freezing Rain

When there’s a sheet of ice on roads and runways, it’s time to rethink travel plans. Freezing rain, while less common, reduces the braking effectiveness of aircraft while landing. But it doesn’t stop aircraft from landing. Taking off is another question.

Few de-icing fluids can last long enough, from application to take off, in severe freezing rain conditions. This is called “holdover” time. Due to this narrow time window, you may not have enough time to taxi to the runway, wait your turn behind other aircraft, and take off. When this happens, airlines delay flights until conditions improve. The good news is that freezing rain storms are relatively rare, even in snowy destinations.

Mountains also have an effect on weather, as they push air upwards. As air moves into higher altitudes, it gets colder and can’t hold as much water content, which causes the moisture to condense and form clouds. Here, you can see that effect with the higher cloud in the top left. Captured by Boom Supersonic Aerodynamics Engineer Phil Coyle, this majestic view over the Rocky Mountains east of Steamboat Springs, Colorado shows weather moving across the mountains. At the time, it was clear back in Centennial (near Denver) where Boom is headquartered.
Extreme Heat

Hot air is less dense, which reduces the amount of thrust the engines produce. The result? An aircraft may struggle to get enough speed to take off. It’s more common than you might think, especially in regions with consistently high temperatures.  

To compensate for reduced engine power during extreme heat, airlines will reduce the weight of the aircraft by removing bags and cargo, and limiting the number of passengers. The lighter the aircraft, the easier it is to reach take off speed. But ultimately, some aircraft won’t get off the ground in the most extreme heat conditions.


When a thunderstorm passes through an airport, the airport usually closes down or reduces operations. That means no flights in or out. Why?

  1. Thunder and lightning often go hand-in-hand. As you might expect, airports mitigate the risk of an aircraft lightning strike by halting or limiting flights.
  2. When there’s a risk of lightning, airports order all ground personnel to go indoors for their safety. As a result, there are no ground crews to support take offs and landings.
  3. Excessive winds create dangerous conditions, making it unsafe to fly.

Captured by Ed Hopkins, Boom Supersonic Aviation Software Consultant, here is a view of the Sandel Avionics King Air 200 with Avilon installed. On this flight, Hopkins is the Flight Test Engineer and the crew is flying through a cloud en route to the Navy flight test area offshore from Palomar Airport near San Diego, California. According to Hopkins (and all pilots), this is where you trust your instruments!
Wind Shear and Microbursts

You can’t see wind shear or microbursts out the window at the airport. A wind shear is a sudden change of direction or intensity of the wind. It triggers a rapid increase or decrease in aircraft speed during flight. A microburst is like wind shear on steroids: it’s a severe downdraft. Both are to be avoided, which is exactly what pilots do. No aircraft should take off or land with wind shear or microbursts. Hence, flight delays.

A microburst is a small concentrated downburst that produces an outward burst of strong winds at the surface. Photo courtesy of The NOAA National Severe Storms Laboratory.
Hurricanes and Typhoons

Some say hurricane, others say typhoon. Either way, they are Mother Nature’s most powerful storms. When one is on its way, airports close and airlines cancel flights. Airlines even move their planes to airports that are outside the path of the storm. Why? Because extreme conditions can destroy even large aircraft. Simply being parked on the runway during a hurricane or typhoon is dangerous. For everyone’s safety, airports usually close well before these storms arrive — and most airport communities and nearby cities may be evacuated.

Volcanic Eruptions

Aircraft shouldn’t fly through volcanic ash, which can cause minor or even catastrophic engine damage. You must fly around the ash. Not surprisingly, these unexpected detours wreak havoc on flight routes and cause delays. Taking the long way round isn’t always feasible, but it’s the only safe option for commercial aircraft.


Are earthquakes weather? It’s debatable. Regardless, earthquakes impact infrastructure in and around airports. They can cause damage to runways, taxiways, airport facilities, air traffic control towers, and surrounding roads and railways. A powerful earthquake can also damage the power and telecommunications grid, as well as water and sewage systems, making running an airport impossible. It can take days or even weeks to return to safe operating conditions, which means few to no flights in or out.

Safety Comes First

During any of these weather events, the safety of workers comes first. From the baggage handlers to the rampers, from the marshallers to the fuelers, and from the wing walkers to the tug drivers, these workers are on the front lines of bad weather. For their safety, airports cease ground operations during extreme weather. Flight delays and cancellations naturally follow. Operations resume when the bad weather passes.

Smoke from forest fires can also trigger flight delays. In Colorado, smoke from the Granby / East Troublesome fire in 2020 caused TFRs (Temporary Flight Restrictions), requiring aircraft to route around the smoke. Captured by Boom Supersonic Senior IT Systems Engineer John Cameron.
Wishing you blue skies and tailwinds

While weather can’t be blamed for all flight delays (we’re looking at you, mechanical failure), it accounts for most travel disruptions. But don’t blame your local weather. Major weather events in far-flung locations can trigger a cascade of delays because flight crews — and their aircraft — constantly travel between airports and weather systems. A snowstorm in Toronto can delay your flight in San Francisco, and so on.

And that’s why pilots traditionally wish each other blue skies and tailwinds before a journey.


Subscribe to the newsletter for Boom news and insights straight to your inbox.

This field is for validation purposes and should be left unchanged.

Tagged in

Read more

Stay up to speed

Subscribe to the newsletter for Boom news and insights straight to your inbox.

This field is for validation purposes and should be left unchanged.