It is not likely that the company with which you are flying will allow you to cancel a flight because the sun is not shining. Postponements or rescheduling of a flight must be made in accordance with the particular company’s policies. While balloon flights are extremely dependant upon the weather, if it is determined by the company that the weather that day is safe for ballooning, your flight will take place. Flights cannot take place on rainy or foggy days, but it cannot be guaranteed that the sun will be shining.