UTCTime package:text-icu

utcTime :: Calendar -> UTCTime
text-icu Data.Text.ICU.Calendar
Convert the day and time part of the calendar to a UTCTime. 
>>> import qualified Data.Text as T

>>> c1 <- calendar (T.pack "CET") (Locale "de_DE") TraditionalCalendarType

>>> show c1
2021-10-12 18:00:50

>>> utcTime c1
2021-10-12 16:00:50.544999999998 UTC