Roy has a
semi-arid climate (
Köppen BSk) with cold winters except when moderated by
chinook influences that will typically push maximum temperatures over on seventeen days during winter and twelve days each in November and March. Spring is mild and frequently thundery, whilst summer days are hot – sometimes very hot – but nights are usually pleasantly cool. Precipitation is fairly scarce, mostly coming from thunderstorms during late spring and summer, whilst snowfall averages (the median is ) but significant falls occur on only a minority of winter days. However, during the cold winter of 1977–78, cover reached on February 19 and averaged for the whole month of February. }} ==Demographics==