Research indicates most lightning strikes occur in what conditions?

Lightning strikes are most commonly observed in conditions involving the presence of moisture and strong upward air currents, which are typically associated with thunderstorms. Research indicates that most lightning occurs in warmer conditions, particularly in the vicinity of the freezing level, where temperatures are between 0°C and 8°C.

At these altitudes, water droplets can exist in a supercooled state, which is essential for the process of charge separation that leads to lightning. The dynamic conditions in and around thunderstorms allow for the mixing of water droplets at differing temperatures, leading to the build-up of static electricity, which results in lightning discharges.

The other options describe conditions that do not align with the most common situations for lightning occurrence. For instance, saying lightning occurs only in clear weather fails to account for its dependence on the atmospheric dynamics in thunderstorms. Conditions above 7,000 feet typically are associated with a lack of sufficient moisture and upward movement necessary for thunderstorm development. Similarly, temperatures below 0°C are not favorable for the growth of thunderstorms where lightning strikes are most prevalent.