Earth's seasons — winter, spring, summer and autumn(or fall) — are caused by the yearly revolution of the Earth in its orbit around the sun and the planet's tilt. When the Northern Hemisphere is pointed toward the sun, it is summer, and when it is pointed away, it is winter (and vice versa for the Southern Hemisphere). Summer and winter are heralded by their respective solstices, while spring and fall begin at an equinox, when the sun crosses Earth's equator and night day are roughly equal length. Below, our stories that relate to Earth's seasons and the ways they affect us.
A blast of sweltering heat will sweep across the United States over the next four days, and some places will see temperatures as much as 10 to 15 degrees Fahrenheit above average for this time of year, according to the National Weather Service.