The  CW just published the schedule for Midseason premieres.
 
Supernatural will return Thursday January 18.
 
Here's the entire schedule
MONDAY, JANUARY 1
8:00-9:00 PM SUPERGIRL (Encore)
9:00-10:00 PM VALOR (New Episode)

FRIDAY, JANUARY 5
8:00-9:00 PM CRAZY EX-GIRLFRIEND (New Episode)
9:00-10:00 PM PENN & TELLER: FOOL US (Encore)

MONDAY, JANUARY 15
8:00-9:00 PM SUPERGIRL (New Episode)
9:00-10:00 PM VALOR (New Episode)

TUESDAY, JANUARY 16
8:00-9:00 PM THE FLASH (New Episode)
9:00-10:00 PM BLACK LIGHTNING (Series Premiere)

WEDNESDAY, JANUARY 17
8:00-9:00 PM RIVERDALE (New Episode)
9:00-10:00 PM DYNASTY (New Episode)

THURSDAY, JANUARY 18
8:00-9:00 PM SUPERNATURAL (New Episode)
9:00-10:00 PM ARROW (New Episode)

FRIDAY, JANUARY 26
8:00-9:00 PM CRAZY EX-GIRLFRIEND (New Episode)
9:00-10:00 PM JANE THE VIRGIN (New Episode)