Short answers, pulled from the story.
Gary Gygax created the first session of Castle Greyhawk in the late autumn of 1972. The children played their first session around 9 PM fighting giant centipedes and scorpions in rubble that glinted with coins.
The first players to explore Castle Greyhawk besides Gary Gygax's children included friends Don Kaye, Rob Kuntz, and Terry Kuntz about a month after the initial session. Play sessions occurred seven or more times a week sometimes drawing over twenty gamers into his basement on weekends.
Oerth has an axial tilt of thirty degrees which causes greater seasonal temperature variation than on Earth. Wizardly and divine magic shifts weather patterns to be more favorable to the populace across the planet.
The World of Greyhawk folio edition was released in August 1980 after being originally intended for early 1979. It consisted of a thirty-two-page booklet and a thirty-four-inch by forty-four-inch two-piece color map of the Flanaess.
The Scarlet Brotherhood expanded the Olman pantheon and newly introduced the Touv people including their nine gods. This area further explored Mictlantecuhtli Tezcatlipoca and Quetzalcoatl as part of the new religious additions.