Many runners consider the cooler months of spring to be the best of the year for getting outside for your miles. Often, when getting dressed, all you have to do is throw on a short-sleeved T-shirt and leggings or shorts. You don’t need several layers like you do during winter, and you’re not sweating buckets like you do in the summer.

However, even when the temperature feels great, you may start to notice that certain weather variables—humidity, wind, and rain, to name a few—can throw off your wardrobe game, leaving you stressed about overheating or freezing your butt off before you even walk out the door.

You can take the guesswork out of getting dressed with our what-to-wear tool, which will recommend the right gear for you depending on the conditions outside. It has a whole new look and is ready to help you run comfortably and confidently.

Remember, no matter what the temperature says, your body is going to heat up as soon as you start moving. A solid rule of thumb: Dress like it’s 15 to 20 degrees warmer than it actually is. Our What to Wear Running Tool takes into account factors like this, along with how other various conditions can change the real feel of any given run.

“You should be uncomfortable standing outside as you wait for your watch to sync,” says Elizabeth Corkum, a New York City-based running coach. “If you’re fine simply standing outside, the odds are good you’ll overheat once you warm up into your run.”

The ideal temperature for marathon running, by the way, is 45 degrees Farenheit, according to research published in the journal PLOS One. However, if you’re running at a slower speed and with less intensity, you may feel more comfortable at a higher temperature (typically in the 50s or 60s).

“If you’re going all out for that long at that temperature, you’re generating so much heat that the cool air environment allows you to be the most efficient,” says Doug Casa, Ph.D., chief executive officer of The Korey Stringer Institute, which provides research on exertional heat stroke prevention.

Not sure what kind or style of gear to invest in? Check out the links below for some of our favorite seasonal recommendations.

The Best Men’s Long-Sleeve Shirts

The Best Women’s Long-Sleeve Shirts

The Best Base Layers for Colder Runs

Our Favorite Vests for Cooler Runs

Cold-Weather Jackets to Make Winter Running Bearable

Running Gloves You’re Sure to Love