Many see summer as a time for vacations and lazy days under the sun, but the warm weather brings a slew of issues for poor families, including a growing number of families in homeless shelters.

Urban areas are especially hit by the “summer surge” of homelessness. New York City’s homeless population is up more than 20%, possibly because of higher unemployment. But the trend isn’t exclusive to the Big Apple. In Toledo, Ohio, overcrowded shelters are turning away dozens of people every night. In Charlotte, N.C., a shelter that is usually only open in the winter has stayed open for the summer to meet rising demand.

So what causes the swell?

• Landlords are more likely to evict in the summer months.
• Parents who’ve put up with poor housing conditions to spare their kids from the harsh realities of homelessness, including teasing in school, finally pack up and leave.
• Relatives who’ve taken in family members lose their patience with kids who are off during the summer.

What can you do?

• DoSomething and Staples are making it easy for you to help the 13 million children in the US that live in poverty by getting them the basic supplies they need to go back to school.
• Organize an event for homeless kids, like a movie night or dinner.
• Produce your very own mini documentary about the situation of homeless teens in America.