Retconning the ambiguous uncertainty of the second film's ending, Arnold Schwarzenegger returns without good reason as the T-850, an advanced model assigned to protect John Connor and his future wife from another more advanced model.
After 12 years waiting, Jonathan Mostow gives a rehash of T2, written by the creators of Married with Children. FUCK YOU, Jonathan Mostow!
The date is affirmed by the watch the T-850 examines reading "07.24.2004". Controversial ages and dates listed are clearly the result of poor writing and are to be ignored. The T-X also jumpstarts Skynet with some new info, allowing for the early development of the T-800 in 2018?
Jul 4, 2032 - Timeline 3
The T-850 admits to infiltrating and terminating John Connor on July 4th, 2032. The T-850 is then captured and deactivated.
2033 - Timeline 3
Skynet sends the T-X back in time to terminate his lieutenants. The T-850 is sent back to protect John's lieutenants, and during his system reboot, 2033 is a year mentioned in his system logs, meaning he has been in that time.