Several countries around the world have year-round schooling or schooling programs. Some of these countries include China, Japan, Nigeria, Australia, South Korea and North Korea. The school terms in these countries typically run for 11 months on a trimester or quarter system, wherein a week or so of vacation exists between each term.
Year-round schooling is a bit of a misnomer, as several countries have academic years that go nearly year round, but have one month given over to breaks or vacation. For example, Japan begins its school year in April and it ends the following March. Japan is on a trimester system and there are breaks between each trimester. Australia has a similar system in that the school year begins in late January and ends in mid-December. Students then have roughly a month and a half off before beginning a new school year.
The United States has the shortest school year, as it typically begins in early September or late August and runs into the following mid-June. However, nearly every state, save Wyoming, Mississippi, Maine, New Hampshire and Rhode Island, has some type of year-round schooling system in place. Kids who attend year-round schools typically have higher test scores and retention rates.