actual reported temperature is at or below any
published cold temperature restriction, or pilots with
automatic cold temperature compensating systems
must ensure the system is on and operating on each
designated segment. Advise ATC when intending to

apply cold temperature correction and of the amount
of correction required on initial contact (or as soon as

possible) for the intermediate segment and/or the
published missed approach. This information is
required for ATC to provide aircraft appropriate
vertical separation between known traffic.

REFERENCE-
AIM, Paragraph 7-2-3 , Altimeter Errors
AIM TBL 7-2-3, ICAO Cold Temperature Error