From May to July, people will get more tick bites than any other time.
While more than 30,000 cases of Lyme disease are confirmed nationwide each year, studies suggest the actual number is closer to 300,000.
Ticks can also carry other serious illnesses.
Dr. David Agus told "CBS This Morning" that two warm winters in a row are partly to blame for the surging number of ticks. Another reason is that there has been a record harvest of acorn—a favorite food of mice in the wild.
"Acorns are what mice eat and mice carry ticks. So with mice happy and running around, we're going to see more ticks this year," Agus said.
Lyme disease is one of the most common illnesses associated with ticks and one of the more difficult to diagnose.
"The real problem is ... the one FDA-approved Lyme test doesn't really turn positive in most cases 'til four to six weeks afterwards, and not even in all cases does it turn positive," Agus explained. So people who were more recently infected might get a false negative test result.