There are usually 365 days in a year because it takes the Earth approximately 365 days to orbit around the sun. However, every four years there is usually a year with 366 days, known as a leap year, because the Earth act... More » Science Time & Calendars

One year is measured by the time it takes a planet to orbit the sun, and 365 days is the best estimate for how long it takes Earth to complete a full trip around the sun. Years on other planets are measured in comparison... More »

The National Oceanic and Atmospheric Administration's website explains that the tilt in the earth's axis means that during different times of the year, different parts of the earth are pointed toward the sun, resulting i... More »

In the Northern Hemisphere, the official summer season begins with the June solstice, which takes place on June 20th, 21st or 22nd each year, and ends with the September equinox, which takes place on September 22nd or 23... More »

The days start getting longer every year after the winter solstice, which falls on the first day of winter, the shortest day of the year. The first day of winter is typically December 21 or 22 in the Northern Hemisphere. More »

The number of school days in a year depends on the state; 30 states have 180 school days, according to Education Commission of the States, 2013 update. Two states set minimum school days higher than 180 days, and 11 stat... More »

Calculating your age in days is a fairly simple calculation of multiplying your age by the days in a year and adding the days since your last birthday. Make an adjustment for leap years. More »