I have a DC2R (2000 model) and the temp on it sits a about 3/8's as well... But I do the Hume Hwy (Canberra to Syd) run once a month normally and the temp will get down to under 1/4 I'd say...

Like Savant said, Its winter outside, dont take it as much... (just be thankful its not sitting on the OTHER side of that 1/2 way marker )