Americans are suffering through a very bad cold season — but not a terrible flu season, which would be far more threatening, according to the makers of a smart thermometer that accurately tracked last year’s highly lethal flu season.

Nearly 1 million American households use Kinsa Health’s internet-connected thermometers and they submit about 40,000 readings a day. This week, about 10 percent more Americans have fevers than did even at the peak of last year, the company said.

“Lots of people are sick — but they have colds, not flu,” said Inder Singh, founder of Kinsa Health, in a telephone interview.

The company made that conclusion, he said, based on how long the fevers lasted. Typically, a cold’s fever lasts only a day or two, while the fever that accompanies flu lasts three to seven days.