Extremes have ranged from − 18 ° F ( − 28 ° C ) on February 9 , 1934 , up to 104 ° F ( 40 ° C ) on July 4 , 1911 .
The hottest month is July , with a normal temperature of 73.4 ° F . The coldest month is January , with a normal of 29.0 ° F. Extremes have ranged from − 18 ° F on February 9 , 1934 , up to 104 ° F on July 4 , 1911 .