Climatological Data: Ohio, May 1898-1975. (Requires DjVu Plug-in)

Climatological Data and other climate publications for all states, c.1880's on (Free to .edu domains)

Climates of the States: Ohio.

Monthly Normals of Temperature, Precipitation, and Heating and Cooling Degree Days 1941-1970: Ohio.

Monthly Station Normals of Temperature, Precipitation, and Heating and Cooling Degree Days 1971-2000: Ohio.