Duchesne in January? Are you actually backpacking in the mountains or fishing at Starvation? So, what is your actual destination? If you go in the mountains at all, expect -20's for the low, with lots and lots and lots of snow. If you stay in the valley at 5000 ft (which is were Duchesne is at) then what you said is normal for temperatures. There also won't be that much snow in the low valleys.