through ha tanti significati, ma è anche un avverbio di tempo:

We've got a tough programme, hard work right through to the summer...
ADV: ADV after v

If something happens from a particular period of time through another, it starts at the first period and continues until the end of the second period
. (AM; in BRIT, use to)
...open Monday through Sunday from 7:00 am to 10:00 pm...

See also date

time expressions