In Altoona the prevailing winds will be channeled more from the south in the summer and fall and more from the north in the winter and spring. Precipitation is fairly well distributed throughout the year, but nearly 60 percent does fall in the spring and summer season. Extended periods of drought are seldom experienced with the longest dry period 26 days from August 24 to September 8 in 1964. The highest monthly total was 12.35 inches in June 1972 and the greatest 24 hour rain was 4.30 inches on August 21-22, 1889. The return period of a similar 24 hour rain shoudl be about 25 years.
Thunderstorms can occur anytime, but are most frequent in the late spring and summer months.
Other than creating a rainy period, hurricanes do not significantly affect the Altoona area. Since over 100 people have been killed and 900 injured by Pennsylvania tornadoes, it is obvious that Blair County is an area of minimal severe storm activity. Edited with data current through December 1996.