ARRL Field Day
ARRL Field Day is the single most popular on-the-air event held annually in the US and Canada. On the fourth weekend of June of each year, more than 35,000 radio amateurs gather with their clubs, groups or simply with friends to operate from remote locations.
Field Day is a picnic, a campout, practice for emergencies, an informal contest and, most of all, FUN!
It is a time where many aspects of Amateur Radio come together to highlight our many roles. While some will treat it as a contest, other groups use the opportunity to practice their emergency response capabilities. It is an excellent opportunity to demonstrate Amateur Radio to the organizations that Amateur Radio might serve in an emergency, as well as the general public. For many clubs, ARRL Field Day is one of the highlights of their annual calendar.
-- read more at What is Field Day?
SPAR Winter Field Day
Not only during Field Day in June, do the bands come alive with improvised signals proving the ability to respond to emergencies. Since emergencies and natural disasters don't always happen in the summer, during Winter Field Day, frigid winds, icy limbs and bitter cold replace the thunderstorms and blistering heat of summer. In 2007 SPAR established a Winter Field Day event and invited all Amateur Radio operators to participate. The event was repeated in 2008 and was considered a success, so it was then designated an annual event to be held the last full weekend each January.
--- read more at SPAR Winter Field Day