| Junior Ranger Day | 05/17/2025 9:00 AM - 12:00 PM | Not Included | Not Included | Other:Junior Ranger Day  |
| Junior Ranger Day | 08/15/2015 9:00 AM - 1:00 PM | Not Included | Not Included | Not Included |
| Junior Ranger Day | 08/11/2018 10:00 AM - 12:00 PM | Not Included | Not Included | Not Included |
| Junior Ranger Day | 07/15/2017 10:00 AM - 12:00 PM | Not Included | Not Included | Not Included |
| Junior Ranger Day | 08/20/2016 10:00 AM - 1:00 PM | Not Included | Not Included | Not Included |
| Joint Meeting - City Council and San Marcos Creek Oversight Committee | 06/25/2018 6:00 PM - 8:00 PM | Agenda:Agenda_Joint Meeting_062518  | Not Included | Not Included |
| Join the City of San Marcos & SANDAG for Bike Anywhere Day! | 05/15/2025 6:30 AM - 9:30 AM | Not Included | Not Included | Not Included |
| January 5 | Las Posas Park, 2nd San Diego Aqueduct, Lake Wohlford Flume, Blue Bird Cyn. | 01/05/2019 9:00 AM - 12:00 PM | Not Included | Not Included | Not Included |
| Jammin Through the Decades Concert | 08/10/2012 7:30 PM - 9:00 PM | Not Included | Not Included | Not Included |
| Jammin Through the Decades Concert | 07/20/2012 7:30 PM - 9:00 PM | Not Included | Not Included | Not Included |
| Jammin Through the Decades Concert | 06/15/2012 7:30 PM - 9:00 PM | Not Included | Not Included | Not Included |
| Jack's Pond Nature Center - Reptile Day | - | Not Included | Not Included | Not Included |
| Jack's Pond Nature Center - Project Wildlife/Bird Basics for Kids | - | Not Included | Not Included | Not Included |
| Jack's Pond Nature Center - Bugs & Insects Program | - | Not Included | Not Included | Not Included |
| Jack’s Pond Nature Center - Family Solar Fun Day | 09/08/2012 9:00 AM - 1:00 PM | Not Included | Not Included | Not Included |
| Intergenerational FunDay! | 09/10/2016 8:00 AM - 1:00 PM | Not Included | Not Included | Not Included |
| Insects Day | 06/27/2015 10:00 AM - 11:00 AM | Not Included | Not Included | Not Included |
| Innovation Park Ribbon Cutting Ceremony | 10/12/2017 5:00 PM - 6:00 PM | Not Included | Not Included | Not Included |
| Inland Rail Trail Workshop | 06/12/2013 5:30 PM - 7:30 PM | Agenda:Inland Rail Trail  | Not Included | Not Included |
| Independence Day-City Hall Closed | 07/05/2010 7:30 AM - 5:30 PM | Not Included | Not Included | Not Included |