Graphics.Gnuplot.Time

Documentation

prepXTime :: (FormatTime a, Read b) => [(a, b)] -> [(b, b)]

Use it this way:

import Data.Time
import Graphics.Gnuplot.Simple

main =
   plotPath [XTime, XFormat "%m-%d"] $ prepXTime $
      (UTCTime (fromGregorian 2008 01 01)     0, 1.0) :
      (UTCTime (fromGregorian 2008 01 05) 43200, 5.0) :
      (UTCTime (fromGregorian 2008 01 15)     0, 2.5) :
      []