Baltimore Weather

Baltimore area weather is influenced by weather patterns generated in three major climate regions: the temperate, continental climate of the North and Central U.S., the mild and sometimes tropical conditions of the South and the maritime influence of the Western Atlantic Ocean and Chesapeake Bay. The rough terrain of the Appalachian Maountains has a modifying effect on the interaction of these climate regions.

Precipitation is well distributed throughout the year. Thunderstorms and the remains of hurricanes give the sumer and early autumn months the greatest totals. Snowfall occurs on an average of 22 days per year and is often mixed with rain or sleet. Baltimore's record snowfall was January 27-29, 1922, with a total of 26.5".

The average date of the last freeze in Baltimore is in mid-April, the first freeze in late October. The "freeze free" period is approximately 194 days. Baltimore's fabled summer heat and humidity is brought on by an Atlantic ridge of high pressure known as the "Bermuda High". This circulation pattern pumps warm, humid air into the region from the deep South. Brief periods of relief from the summer heat come in the form of storms from the Central U.S. and Canada.

Wind Chill

The Wind Chill Index was originally developed by the U.S. Army to help determine the effects of cold weather on the human body. It reflects the "chilling" effect that wind has on exposed flesh. It is most useful in determining when frostbite will be a hazard. In day-to-day use during the winter months the wind chill factor is popularly utilized as an "it feels like" temperature reading.

Apparent Temperature

Apparent temperature or humiture is more or less the summertime replacement for wind chill. It is an expression of the effects of heat & humidity on the human body. As with wind chill, it expresses and "it feels like" temperature reading. The higher the relative humidity, the less efficient the body's cooling mechanism becomes and the "apparent temperature" begins to rise. When the apparent temperature reaches the 100 degree category, there is real danger of sunstroke, heat cramps, heat stroke or heat exhaustion.

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