There are 143 sleeps (143 days) until March 15 (Monday, March 15, 2027).
There are 143 days until March 15 (Monday, March 15, 2027) — 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 March 15. Sleeps are the same as days.
143 sleeps is 20 weeks and 3 sleeps.