Extreme weather can be caused by many things such as rain, hot weather, high speed winds and Ect.
Now I will answer the main question...
How does extreme weather affect us?
Too much rain can cause flooding which can destroy buildings, and can lead to loss of lives. Floods can also lead to diseases such as water bone disease.
What to do in case of a Flood
you shouldn't wait until you start seeing is rise,immediatly go to high ground and don't drive in flooded areas.
Hot weather for a long period of time without any rain can lead to a drought which can lead to wildfires and dust storms which can lead to houses burning down and more.
What to do in case of a Drought
Avoid long term showers and stick with short ones and don't let yhe water run whilst brushing your teeth.
High speed winds can lead Tornadoes which can destroy buildings and farms, which lead to loss of lives and shortage of food.
What to do in case of a Tornado
Go to a basement or a ground floor room such as a bathroom, a closet or a hallway . If you have no basement then find shelter under a heavy table or desk and in all causes stay away from windows, walls and doors.