Allentown's climate is called humid continental. Summers are hot and muggy, fall and spring are mild, and winter is cold. Precipitation is almost spread throughout the year at the same rate. Allentown's weather is affected by the Blue Mountain, a mountain ridge from 1,000 to 1,600 feet high about 12 miles north of the city, and South Mountain, a mountain ridge of 500 to 1,000 feet high that is south of the city.