Karen Carpenter nailed it. Rainy days — and Mondays — do get us down.

A new study by The Ohio State University says people are more likely to have a negative experience at a restaurant and provide unfavorable remarks on comment cards during rainy weather.

“Restaurant managers may see more than the usual bad reviews on certain days, and it may have nothing to do with the service or the quality of the food,” Milos Bujisic, co-author of the study and assistant professor of hospitality management at Ohio State, said in a prepared statement. “Restaurants can’t control the weather, but it may affect how customers review them.”

Researchers studied 32 Florida restaurants that are part of the same national fast-casual chain and found that customers left more negative remarks on comment cards on days when it was raining. The results showed the odds of patrons leaving very negative comments versus very positive comments were 2.9 times greater on rainy days.

The research appears online in the "Journal of Hospitality and Tourism Research" and will be published in a future print edition.

Two other online studies done in other parts of the country have suggested that unpleasant weather left people in bad moods, which was then linked to them having less positive views about the restaurants they visited, the researchers said.

Poor service and bad food are bigger factors, but the weather can't be ignored, co-author Vanja Bogicevic, a visiting assistant professor of hospitality management at Ohio State, said in a prepared statement.

"It may be a smaller factor, but it is something that managers should pay attention to,” Bogicevic said.

The researchers examined 14 different weather variables, but only three were related to customer comments: rain, temperature and barometric pressure. Higher temperatures were linked to more negative comments.

It's not just customers who get crabby during poor weather. The wait staff may be affected, too.

“A rainy day may put employees in a bad mood and that will affect their service,” Bujisic said. “Managers need to explain that to their employees and work to keep them motivated.”

Bogicevic also suggested that restaurant managers try to boost customers’ moods during unpleasant weather.

“Think about creative strategies to make customers happy. Maybe offer a free drink or play more upbeat music,” she said.

Other co-authors on the study were H.G. Parsa of the University of Denver, Verka Jovanovic of Singidunum University in Serbia and Anupama Sukhu of the University of New Hampshire.