The further north and south of the equator one goes, the
higher the frequency of storms drops to zero at the poles
or sub-polar regions. In addition, the average strength of
thunderstorms decreases as we moves away from the equator.
Heat and humidity are the causes thunderstorms. The heat
is in greater quantities near the equator which is the reason
for the high frequency of storms in the area. In
the eastern U.S. the thunderstorms are more numerous and more
violent than in Europe because at the same latitude the cold
and dry air from the North Pole meets the Gulf of Mexico which
is warm and humid.
Each year there are around 20
million thunderstorms or 50.000
per day. At any time on the planet, there are more than 2000
active thunderstorms about 100 lightning strikes hitting the
ground every second.
Thunderstorms occur mainly in summer (June-August in
the northern hemisphere and December to February in the southern
hemisphere). But it is possible that small thunderstorms occur
The above image from NASA shows the
annual density of lightning through
the world. Note that the highest concentration is in the Central
- 200 +
The annual average
of the days of thunderstorms on all continents
here to enlarge map
Average density of lightning strikes
in hundredths of impacts per km2 in 1994
The frequency of storms by departments
Source : the bible of Alex Hermant "traqueur d'orage"
Average density of the lightning USA
Régnier helped me correct mistakes, please you to visit
Im not english speaker, some improprieties can appear
to english masters.
Could you help me reporting by mail any fault you read. Thank
you for all.