the weather outside has been dangerously scary for much of the nation.
"Extremely cold temperatures affect white blood cells, so temperatures are an obstacle to fighting infection," said Dr. Len Horovitz, pulmonologist and internist at Lenox Hill Hospital in New York.
The good news is that, according to ABC News meteorologists, the gel will start to melt with milder temperatures.
Some people are wondering, however, because of the warmer weather: Are rapid temperature fluctuations harmful to my health?
This combination of photos taken on January 30 and 31, 2019 shows pedestrians protecting their faces from the cold in New York, Washington, Chicago, Kingston, Ontario, Montreal and along Lake Michigan.
Mr. Horovitz said that a person is no longer at risk of getting a cold or flu when the mercury is heating up dramatically in a short time.
"You catch colds and flu from other people, not the weather," he noted.
He added, "The warm-up will not put people at greater risk of catching a virus, but people should not let down their guard. It's still cold and the flu season so stay alert. Dress for the weather, wash your hands frequently, do not put your hands near your face. "
Horovitz said people tend to be more sociable as the weather gets warmer and goes out more often. It means being exposed to more people – and more germs.
Unlike extremely low temperatures, a rapid increase does not have the same impact on white blood cells; it is therefore unlikely that your immune system will be compromised, he explained.
"High temperatures do not have that effect," he said.
His last tip: do not give up.
"Continue washing your hands thoroughly on both sides with warm soapy water and do not touch your face," he said.
Remember, flu season does not usually end until March.
Eric M. Strauss is the editor of the ABC News Medical Unit and would like to receive your comments on Twitter: @ericMstrauss.