Weather is probably a major factor when you plan your trip to Windsor, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually August and July, with an average temperature of 17°C, while the coldest months are February and January, with an average of -1°C. The snowiest months in Windsor are February, January, December and November, with each month seeing an average of 44 cm of snowfall.