Use either:

• the 2034 calendar (spring equinox is on a new moon)
• the 2039 calendar (summer solstice is on a new moon)

Major events marked in yellow

The year is approximately 2024

March 20th (Spring Equinox) — Sudo delivers the puzzle to Lu

March 24th — Lu reunites with Tavi and meets Ollie

The nearest saturday morning — Gershom and the girl meet

April 20th — Tavi and Gershom solve the puzzle and the rain begins //end part 1

June 21st (Summer Solstice) — Shit hits the fan

September 24th (Fall Equinox) — Dramatic conclusion