Sometimes even the weather can cause us stress when other things in our lives are not going so well. There is some old research that an accumulation of “daily hassles” (e.g. temp above 100, too much laundry, stress at work) is felt by people more strongly (and with more negative effects) that a huge negative event that happens.
One antidote to these daily hassles is to slow down and try to pay attention to your feelings in the present moment. I know, easy to say and hard to do..but worth it.