Nassau police say when the temperature outside rises, so does the number of drunk drivers.

The department says arrests for driving under the influence are up 20% over the last year.

Officer Joseph Fernandez, with Highway Patrol, says the department is putting out extra patrols looking for intoxicated drivers.

"Each precinct also has a dedicated unit, selective enforcement unit. And their primary mission is to go out and seek DWIs," says Fernandez.

Police say they're always on the lookout for drunk driving. The extra patrols will be on the roads throughout the summer.

Doctors say alcohol can lead to heat-related illnesses like heat exhaustion.