Which temperature range provides the highest probability of lightning strikes?

• A. -40 to -20 C
• B. 0 to 10 C
• C. +5 to -5 C
• D. 20 to 30 C

Answer: (C)

Lightning occurs most often in strong convective storms, and the charging that leads to a lightning discharge mainly happens in the colder, middle portions of the cloud where ice particles and supercooled droplets interact. The range around freezing, roughly plus or minus a few degrees, is where these ice-crystal collisions and charge separations are most efficient, so the probability of a lightning discharge is highest there.

In warmer air, storms can form, but the actual discharges tend to occur higher in the cloud where temperatures have dropped toward freezing, and in much colder air the updrafts and mixing needed for persistent charging are less favorable. That’s why the temperature band around 0 to 5 degrees Celsius stands out as the region most associated with frequent lightning activity.