NEW YORK (CBSNewYork) – Although the temperatures haven’t quite caught up yet, it is spring.

And with spring comes an actual transformation in our bodies known as spring fever, even if the heat hasn’t come.

“It’s still kind of wintry but the daffodils have come up. I don’t know how they managed,” said Lynn Nicholas.

Many New Yorkers are wonder the same thing: How have we managed to deal with these unseasonably cold temperatures when we should be basking in the spring sun?

“We used to go shopping and we would buy spring coats, which were very light coats that we would wear in the springtime, which was a real season,” said Manhattan resident Sharon Lerner.

“It pretty much goes from bitter cold to daunting heat,” said Manhattan resident Jennesy Guzman.

Plenty are still trying to make the best of it. Kids are playing in city parks, dog owners are walking their four-legged friends, and others are exercising, possibly trying to run off their winter blues and catch a spring fever.

“We are feeling it. We still have got four layers on. The spring has to come through, but the trees are blooming,” said Manhattan resident Marsha Hurst.

Registered dietitian Nicolette Pace says it’s more about the increased length of the day that will have your spring fever running high.

“This time of year, we’re looking at a real rapid escalation in how long the day is. It’s generally, between April and May, two hours a month,” said Pace. “By the end of May you’re at 15 hours of daylight per day.”

Similar to animals that hibernate in winter, we come alive in the spring. Pace says when our eyes take in more light this time of year (compared to winter months), hormonal shifts happen within the brain.

“What happens with spring fever is a natural decrease in melatonin, that’s a sleep or relaxed-type hormone,” Pace said.

Conversely, Pace says there’s an increase in the hormone serotonin.

“Which is known as your ‘feel good’ hormone that helps with energy, feeling good,” Pace said.

Pace believes this may explain why people are naturally more upbeat in the springtime, even if it’s a cold one.

Studies show the brain is also programmed to fall in love in the spring because it naturally produces more dopamine this time of the year. The chemical is triggered by new experiences.