The Glow Cloud changes colors and drops animals, long before the first animals were born.
Huntokar sits cross-legged in a lake for 10,000 years.
The Mesozoic Era
The area that will eventually house Night Vale is inhabited by a flock of pteranodons. Some of them travel through a rift in time to modern-day Night Vale, though all but one are safely returned.
Earliest human settlement of Night Vale. Some cave paintings remain of settlements and the "inhuman, shimmering shapes that never came closer or went farther away" and watched these ancient settlers from far away (according to Cecil). The original discoverer of the cave paintings tried to power wash them off the falls, as for religious reasons he did not believe in the past.
For his 15th birthday, Cecil Gershwin Palmer is gifted a microphone set, which he uses to record pastiche Night Vale Community Radio shows, modeled after the shows by the host of the time, Leonard Burton. Cecil's ambition is not unseen, as he is invited to intern at Night Vale Community Radio.
As of episode 106, It is becoming more apparent that Cecil Gershwin Palmer may have served his internship in the early 1980's, with the finding of his ID and Cecil's description of himself.
The future site of Night Vale and Desert Bluffs is not yet more than a large, featureless desert. Groups of settlers visit the future site of Night Vale, but only one elects to stay. Lee Marvin announces the foundation of the city of Night Vale, "complete with all the things a home needs: secrets, dread, omnipresent government, and areas that are forbidden!" Early settlers included peace-loving imperialist conquerors and religious leaders who wore "soft meats crowns" made of inverted organs strung around the head, and were supported by Huntokar, the god creator of the city of Night Vale.
After the foundation of the USA, the Faceless Old Woman comes to America in an attempt to find answers to a long ago betrayal.
Summer: An astronaut appears in the center of Night Vale, located where the Dog Park will eventually be built.
First meeting of Town Elder Council, later to become the City Council. All records of this meeting are destroyed.
The Obelisk returns to Night Vale. Citizen chosen: Barry McKenney. Question asked: "How do you cure cancer?" Answer: Given but not properly recorded. 
For the war effort, Night Vale citizens chant around bloodstones for the victory of the United States in World War II. A federal lawsuit later requires Night Vale to take down its 7-story monument to Night Vale's contributions to the War Effort.
The Obelisk returns to Night Vale. Citizen chosen: Sidney Lanyard. Question asked and rejected: "How do you cure cancer?" Impromptu question: Sidney asks if his wife is cheating on him with Gerald Framingham. 
Night Vale is visited by genderless future humans using time travel technology, which is subsequently outlawed.
The city decided to create a public beach made entirely out of municipally burned books.
Danielle DuBois is the current mayor of Night Vale. She writes a poem in honour of nothing that should never not be unknown, Later, in her honor, a monolith in place of the future dog park is erected.
The world in on the brink of nuclear war, caused from mistakenly launched missiles.
Huntokar attempts to remove Night Vale off the world, and thus shatters reality and makes different worlds merge and collide.
Night Vale's pen pals from Nulogorsk, Night Vale's sister city, stop changing the dates on their letters and presumably get stuck in 1983 or are being decimated in the war.
The September 24th issue of the Night Vale Daily Journal, as brought in the submarine from Nulogorsk, has an article with the headline "Sister City Nulogorsk Decimated By Nuclear Attack - No Known Survivors". The Night Vale copy of the same issue has a different front page article, probably because the submarine came from another world.
The Obelisk returns to Night Vale. Person chosen: Susan Willman. Question asked: "What’s your name?" Answer: "Whosoever speaks aloud the name of the Obelisk shall become the Obelisk. Whosoever becomes the Obelisk shall live forever. Whosoever lives forever shall know all things. Whosoever knows all things shall be damned. And whosoever hears the name of the Obelisk spoken aloud shall perish."