How many times has it happened to wear summer canvas shoes, but outside started to rain? Many times, right? They summer shoes nor protect against rain, let alone the moisture that remains inside. Do not think and that you must make them whole 8 hours while you are at work.
For this purpose, see the following video and when weather forecasters are not sure whether outside it will rain or not, make their shoes a protective layer and make no worries. All you need is a candle and fan.