Here is my personal view of the DCAU Timeline. Keep in mind, I haven't seen all of them, so this is just the shows I have seen, or at least information from between series.
Continuity in series
Batman: The Animated Series (1992 - 1995)
- "On Leather Wings"
- On-Screen Dates include:
- June 28 (Computer Screen)
- July 3 (Computer Screen)
- July 13 (Computer Screen)
- On-Screen Dates include:
- "Beware the Gray Ghost"
- On-Screen Dates include:
- October 19, 1992 (Magazine Cover)
- On-Screen Dates include:
- "Joker's Favor"
- On-Screen Dates include:
- March 17, 1995 (Driver's License expiration date)
- On-Screen Dates include:
- "If You're So Smart, Why Aren't You Rich?"
- On-Screen Dates include:
- 1992 (Calendar) - Prologue
- Passages of Time include:
- 2 years after the prologue.
- On-Screen Dates include:
The New Batman Adventures (1997 - 1999)
- "Cold Comfort"
- On-Screen Dates include:
- August 20, 1997 (Check)
- On-Screen Dates include:
- "Beware the Creeper"
- Passages of Time include:
- 7 years after an ex-Valestra Mob hitman became the Joker.
- Passages of Time include:
- Crossovers
- Superman: The Animated Series
Batman Beyond (1999 - 2001)
- "Rebirth"
- Passages of Time include:
- 20 years after the prologue.
- Passages of Time include:
- "Meltdown"
- Passages of Time include:
- ~50 years after Victor Fries became Mr. Freeze.
- Passages of Time include:
- Crossovers
- The Zeta Project
Static Shock (2000 - 2004)
- "Future Shock"
- Passages of Time include:
- 40+ years after present day.
- Passages of Time include:
- Crossovers
- The New Batman Adventures
- Batman Beyond
- Justice League
The Zeta Project (2001 - 2002)
- "Quality Time"
- On-Screen Dates include:
- August 5, 2041 (Computer Mentioned)
- On-Screen Dates include:
- Crossovers
- Batman Beyond
- Batman Beyond
Justice League Unlimited (2004 - 2006)
- "The Once and Future Thing Part Two: Time, Warped"
- Passages of Time include:
- ~50 years after present day.
- Passages of Time include:
- "Epilogue"
- Passages of Time include:
- 40+ years after the Return of the Joker flashback.
- 15 years after "Rebirth".
- Passages of Time include:
- Crossovers
- Batman Beyond
- Static Shock
Continuity in films
Batman: Mask of the Phantasm (1993)
- Passages of Time include:
- 10 years after the flashback.
- Topical References include:
- A Christmas Carol (1843)
- Fortune Magazine (1929 - Present)
- I Love Lucy (1951 - 1957)
Batman Beyond: Return of the Joker (2000)
- Passages of Time include:
- ~40 years after the flashback.
Batman: Mystery of the Batwoman (2003)
- Passages of Time include:
- 9 years after Batman saves a young Sonia Alcana from a fire.
Justice League vs. The Fatal Five (2019)
- On-Screen Dates include:
- November 20?? (Time Sphere)
- Passages of Time include:
- 3 years after Jessica Cruz's camping trip gone wrong.
- 10 months after the prologue.
Continuity in comics
Batman & Robin Adventures (1995 - 1997)
- Annual #1
- Passages of Time include:
- 3 years after Batman: Mask of the Phantasm.
- Passages of Time include:
Batman: Gotham Adventures (1998 - 2003)
- Issue #32
- On-Screen Dates include:
- October 31, 2000 (Newspaper)
- On-Screen Dates include:
Batman Adventures (2003 - 2004)
- Issue #10
- On-Screen Dates include:
- Issue #11
- On-Screen Dates include:
- Issue #13
- Passages of Time include:
Batman and Harley Quinn (2017)
- Issue #1
- Passages of Time include:
- 6 days after Batman and Harley Quinn.
- Passages of Time include:
- Issue #2
- Passages of Time include:
- 2 days after Batman and Harley Quinn.
- Passages of Time include:
- Issue #3
- Passages of Time include:
- 3 minutes after Batman and Harley Quinn.
- Passages of Time include:
- Issue #4
- Passages of Time include:
- 5 days after Batman and Harley Quinn.
- Passages of Time include:
- Issue #5
- Passages of Time include:
- 10 days after Batman and Harley Quinn
- Passages of Time include: