Jacksonville, a very large
metropolitan area covering 840 square miles, extends from the Atlantic Ocean
to about 40 miles inland. Downtown Jacksonville is located some 16 miles
inland on the St. Johns River. The surrounding terrain is level. Easterly
winds blowing about 40 percent of the time produce a maritime influence that
modifies to some extent the heat of summer and the cold of winter. Summers
are long, warm, and relatively humid. Winters, although punctuated with
periodic invasions of cool to occasionally cold air from the north, are mild
because of the southern latitude and the proximity to the warm Atlantic Ocean
waters. Because of the nearness to the ocean, climatic features across the
city vary. For example, during the summer months, temperatures at
Jacksonville International Airport, located 17 miles inland, usually reach
into the lower and mid 90's before being tempered by the sea breezes.
Temperatures along the beaches rarely exceed 90 degrees. Summer
thunderstorms usually occur before the noon hour along the beaches, while
afternoon thunderstorms are the rule inland.
The annual temperature for Jacksonville
is between 68 and 69 degrees. June, July, and August are the hottest
months, with temperatures averaging near 80 degrees. December, January,
February are the coolest months, with temperatures near the middle 50's.
Temperatures exceed 95 degrees only about ten times a year. Night
temperatures in summer are usually comfortable, rarely failing to drop below
80 degrees.
The greatest rainfall, mostly in the form
of local thunderstorms, occurs during the summer months when a measurable
amount can be expected one day in two. Rainfall of 1 inch or more in 24
hours normally occurs about fourteen times a year, and very infrequently heavy
rains, associated with tropical storms, reach amounts of several inches with
durations of more than 24 hours.
The atmosphere is moist, with an average
relative humidity of about 75 percent, ranging from about 90 percent in early
morning hours to about 55 percent in the afternoon. Prevailing winds are
northeasterly in the fall and winter months, and southwesterly in spring and
summer. Wind movement, which averages slightly less than 9 mph, is 2 to
3 mph higher in the early afternoon than the early morning hours, and slightly
higher in spring than in other seasons of the year. |
