Winter is a difficult season for parents and kids alike. Little ones want to run wild outside, but most parents don’t want their children to spend too much time outside in subzero temperatures.

Whether or not it is the harshest winter in decades, frustrated kids still need a place where they can frolic and it is up to parents to come up with ways to help their little ones channel energy while keeping them warm.

That’s where indoor playgrounds come in.

They first appeared in early 2000s in Korea in the form of kid-friendly cafes. Typically, a corner of the cafe might offer Legos, bounce ponies, stuffed dolls or other toys to amuse the children of customers. However, many kids cafes have been transformed in the past few years to be oriented primarily toward children.

Almost all kids cafes today look like small amusement parks, with trains, small theaters and cooking classes.

Another noteworthy trend in a move toward franchises that mostly rely on popular cartoon characters.

Even E-Land Group, the nation’s apparel mogul, jumped on the bandwagon with the opening in July 2011 of the first branch of CocoMong Kids Land in Munjeong-dong, Songpa District. In its first year, the 2,000-square-meter indoor amusement park attracted 250,000 visitors along with 6 billion won ($5.2 million) in sales.

The industry targets young children - usually age 13 and under - who don’t have access to rides at ordinary amusement parks.

Of course, there is a downside with these indoor playgrounds. “Winter is a season when all types of viruses are active,” says Choi Se-won, an otolaryngologist at Malgun Virgin Mary Ear-Nose-Throat Clinic in Gaebong-dong, southwestern Seoul. “The best thing is avoiding a place where there are a large number of people, but if that is not possible, the next best thing is to wash the hands of your children as often as you can.”

And as in any place crowded with young children, accidents are bound to happen.

Nonetheless, indoor playgrounds are still some of the most popular hangout places for families during the winter.