The transition from winter to spring brings many things pretty flower buds, sunnier days, and shorter sleeves and hemlines. Oh, and a cold, according to conventional wisdom. The drastic day-to-day change in temperature somehow messes up your immune system, the thinking goes, making you more vulnerable to viruses.

But is it actually true that the seasonal shift this time of year can cost you sick days Yes—but it’s driven by springtime behavior, not biology. As the weather warms up, people start going out more and becoming more social, and whenever groups of individuals get together and are physically close to one another, cold transmission increases, says Marc I. Leavey, M.D., a primary-care physician with Mercy Medical Center, Lutherville Personal Physicians, in Baltimore.

The other thing is, spring's crazy-wild temperature swings—you know, when it's a balmy 60 degrees one day, and then the next, it's barely above the freezing mark—mean you can be caught off guard and not be dressed to protect yourself from the elements. Going outside in the cold when you're wearing clothes more appropriate for a warmer day can upset your immune system, making you more susceptible to a bug, says Leavey.

With this in mind, the trick to avoiding a spring cold is dressing for the actual temperature outside and not letting spring fever compel you to go to work in a sundress and sandals. Wear layers you can remove if it does warm up in the afternoon, then put [them] back on again if you're out in the evening and the air is chilly, says Leavey. Keep a winter hat and scarf at work or in your car in case temps plunge, and if you're working up a sweat outdoors, remember that it's not quite summer, so pants and long sleeves are still smart.

And just because you can finally pack away your parka, that doesn't give you license to swear off the good hygiene habits that kept you cold-free (hopefully!) all winter. The rules still stand Wash your hands with soap and running water frequently and always before touching your nose, eyes, or mouth, says Leavey. Stay hydrated by drinking lots of water since dry nasal passages and a dry throat make it easier for bugs to get into your system, he adds.

BDST: 1606 HRS, MAR 28, 2015