5. Why does the amount of water that enters a watershed vary throughout the year?

I think that this might be your answer :) I tried hope this helps !

Explanation:

A) Heat exposure Because In terms of weather Heat:  Inhaling hot air, induces airway constriction making it difficult to breathe.

Also Of course, it's known that smoke from fire can have a terrible effect on your lungs. It can restrict oxygen flow, which can and most likely be deadly. So the exposure to the heat will distract them cause they cant breath while they work .