Although it is possible to fly hot air balloons in the rain, it’s not safe to do so, and here’s why:
The temperature of the air inside a hot air balloon can reach 100°C. If rain falls onto the balloon, it cools down the air and the balloon will descend rapidly. The pilot needs to operate the burners to reheat the air to compensate for the air cooling down. A balloon carries a limited amount of propane gas to fuel the burner. In heavy rain, the burner needs to be operated heavily and this could exhaust the supply of propane. Additionally, using the burner extensively could damage the fabric of the balloon.
The rain can make the balloon heavier, which accelerates its rate of descent. Hot air cooling and a heavier balloon make it more difficult to control, and even gentle rain can effect this significantly.
A hot air balloon flight should be comfortable, enjoyable and above all safe. The ideal weather conditions are good visibility, dry and winds of less than 10 miles per hour.
If it rains during a flight, winds can blow the rain to soak the passengers, which would make for an uncomfortable flight.
In good weather, hot air balloons are the safest form of flying. A skilled pilot will be able to land a balloon in the rain, but because of the risks, will never fly if it is raining or rain is forecast.
A hot air balloon flight may be cancelled even when there is no rain at the launch time. This is because the pilot knows that there is a high likelihood that it will rain soon.
Pilots don’t rely on the BBC or local radio station weather forecast because these forecasts are too general. Instead, they check with detailed aviation weather forecasts that show the wind speed and weather conditions in the local balloon take-off area.
Advance weather forecasts are generally not accurate, so it is not possible to predict exactly what the weather will be like for a future flight.
If it has rained heavily before a flight, even if there is no rain on the flight, the landing site may be very muddy. A pilot will still usually fly in these conditions, but the passengers should wear footwear that is suitable for a muddy field.
A hot air balloon flight is a peak experience that is a joy to experience. Passengers often book a trip many months or weeks in advance and are naturally very disappointed if a flight is cancelled because of bad weather.
Hot air balloon pilots love to fly too, but their priority is a safe and comfortable flight, which is why a flight may be cancelled due to bad weather. In these cases, we will reschedule the flight for another date when hopefully the weather is better and you can have a safe flight.