If you have been outside, you've noticed a big difference from Thursday's record-breaking heat. The Tennessee Valley went from temperatures in the teens to summer-like weather in about a week.

Some people believe the weather change causes illness, but health officials say weather might not be to blame.

Students at Chattanooga Preparatory got to sleep in on Friday. Classes were canceled because of illnesses at the school. This week, at least three students were sent home for the flu and some teachers were out sick too.

"At that point, that means we could have a lot of people that could possibly be infected and have the germs in our building and only having one grade we need to make sure we stay proactive," said Tim Gerrish, Principal at Chattanooga Preparatory.

Gerrish said 12% of students are out sick, it's the reason why school was canceled so they can deep clean.

Those students are not alone, some people said they feel sick when the temperature rapidly swings. If you are feeling under the weather, could the weather itself be to blame?

"Even when I was a kid my mother would say don't go out with your head wet because you'll catch a cold," said Sharon Goforth.

It turns out this is a misconception. Sharon Goforth with the Chattanooga-Hamilton County Health Department said weather changes don't make people come down with infectious diseases, but they could make people go indoors when it's colder out.

However, if you feel congested after a warm up, it could be allergies.

"You may have some upper respiratory things going on but it's not because you've suddenly caught the flu or something else because it's gotten warmer, you're probably dealing with an allergy at that point in time," she explained.

Cold can affect people who are asthmatic and people with heart disease. Lower temperatures could give you symptoms, but not an illness.

However, the cold does make people go inside where germs essentially incubate.

"If somebody is sick, that one person if its droplet spread, then we're breathing in the air that suddenly has the virus in it," Goforth said.

It's why Gerrish said he's not taking any chances and teaching his students how to keep germs from spreading.

"Wash their hands when they use the restrooms, hand sanitize after using a tissue and dispose of that tissue as soon as possible," he explained.

The health department said you should also eat nutritious food, stay hydrated and exercise often to protect your immune system.

One easy way to lowering your chances for illness during the colder season is to run an air humidifier; doing so for an hour could kill 30 percent of the airborne viruses.

Chattanooga Prep will use the weekend to thoroughly clean the school before students return on Monday.