Weather will likely play an important role when you plan your trip to Dayton, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually July and August, with an average temperature of 18°C, while the coldest months are February and December, with an average of -4°C. The snowiest months in Dayton are February, January, October and April, with each month seeing an average of 18 cm of snowfall.