What situation could cause a flight to be canceled due to weather?

Heavy rain or snow is a significant factor that can lead to the cancellation of a flight because such weather conditions severely impact the safety and operational capabilities of aircraft. Low visibility, reduced runway conditions, and the potential for icing can create dangerous landing and takeoff environments. Severe precipitation can also influence air traffic control decisions, leading to delays or rerouting that make it impossible to operate a flight safely.

While runway construction can also result in cancellations, it typically wouldn't be attributed directly to weather conditions but rather to operational or maintenance requirements. Low demand for tickets and flight crew preferences are operational considerations but usually do not have the same immediate and severe implications for safety as adverse weather conditions do. Thus, the presence of heavy rain or snow stands out as a concrete reason to cancel a flight, directly affecting its safety and feasibility.