Our word autumn comes from the Latin word autumnus, meaning “to turn”. Fall is the alternative word for the season, and its origin has been traced to the Old English word fellan, meaning "to fall from a height". Back in the 16th Century, in England, this term came to denote the season with expressions such as “the fall of the leaf” and “the fall of the year”.
In Pennsylvania, October is a month of warm days and cool nights. During this month, the trees shut off their food supply to their leaves, allowing the leaves to show off their true colors. While giving us a sample of fall October still has days with a touch of summer, a good time for many activities to be held.
When describing the many foggy October mornings, Carl Sandberg wrote, “The fog comes on little cat feet. It sits looking over harbor and city on silent haunches and then moves on.”
Although there are many different types of fog, fog is essentially a cloud on the ground. In order to form, fog needs moisture in the air, and the air near the ground must be cooled to the dew point. (Dew point is the temperature at which the air can no longer hold all of the water vapor with which it is mixed. Some of the water vapor must condense into liquid water. The dew point is always lower than or equal to the air temperature.)