The first lesson one learns in ballooning is when NOT to fly.
What can be ideal conditions for other activities can often be unsuitable for ballooning. Regardless of the weather conditions at launch time, we must consider the likely conditions when landing. Safety is not an accident. Far better to be on the ground wishing we are up than in the air wishing we are down. Indeed, we're always mindful that the takeoff is optional but the landing is compulsory.
Our policy is to stay on the ground if the wind speed at launch time is 15 kph or more, or if the higher winds are blowing at more than 25 kph, and are likely to mix with the lower winds within 75 minutes of take-off. We are also wary of flying if the temperature at launch time is 15°C or more. Even in Winter, the temperature in the top of our balloon envelopes is about 90°C. On a warm day, the envelope temperature may climb to over 110°C, Long-term operation at these temperatures will cause damage. Flying a balloon on a hot morning with a heavy load can cause long-term structural damage to the envelope fibres, lead to greatly increased porosity, and shorten the life of the envelope by as much as one third.
Although we are able to fly in light rain, we usually choose not to because such conditions tend to be unpleasant. Also, we try to avoid rain because a balloon envelope when packed wet can attract mildew if not dried out promptly.
Other Factors to Consider
Other factors that we consider when deciding whether or not to fly include
- wind direction
- our height above sea level
- the total weight of our balloon and passengers
- the age, health and fitness of our passengers
- the mental and physical state of the pilot on the day
- the presence or not of fog and low cloud
- the existence or otherwise of a low-level temperature inversion
- the existence or not of an approaching cold front and/or rain
- the existence of and/or potential for thermic conditions
- the potential for gusting caused by thunderstorms
- the potential for wind shear and curl-over
- the existence or not of a total fire ban
- our fuel quality and quantity
- fuel pressure, and
- the terrain that we expect to fly into.