Timeline

Ancient history
6000 years ago Over 5000 years ago "Thousands of years ago"
 * The Kindergarten is used to incubate new gems.
 * A battle the location which would later become the strawberry battlefield. Many gem warriors fall. Rose's scabbard is lost.
 * The Galaxy Warp goes inactive.
 * The Crystal Temple is constructed.

The recent past

 * Roughly a couple decades ago, Greg falls in love with Rose Quartz and decides to stay in Beach City.
 * Roughly a decade ago, Rose Quartz records a video for Steven.
 * Roughly 5 years ago, the Aqua Mexican restaurant goes out of business.
 * Roughly a year ago, Connie and Steven see eachother for the first time at the annual boardwalk parade.

Year 1

 * Start of the series.
 * Ocean Gem takes place on the first day of summer, placing the events in the first half of Season 1, including Steven's birthday and Beach-a-Palooza in spring.
 * Horror Club appears to take place around Halloween.
 * Winter Forecast takes place during winter.
 * Maximum Capacity takes place around Beach City's annual New Year's fireworks, marking the end of the year.

Year 2

 * Marble Madness takes place in early spring. The first spring buds can be seen on the trees around the Maheswarans' townhouse.
 * Open Book, Story for Steven and Shirt Club take place before The Return and Jailbreak.