There are 55 sleeps (55 days) until December 17 (Thursday, December 17, 2026).
There are 55 days until December 17 (Thursday, December 17, 2026) — one sleep per night.
One sleep per night between now and the big day — tonight is the first sleep, and the morning after the last sleep is December 17. Sleeps are the same as days.
55 sleeps is 7 weeks and 6 sleeps.