Maybe the fuel has gelled or frozen due to the cold?
It did not start at 10-15 degrees F, but did start when it warmed up the next day.
Is the tank full or nearly empty?
If less than a quarter of a tank you could have too much water in the fuel.
Time to try some Power Service 9-1-1 Diesel Fuel De-Icer and/or maybe some of their cetane booster?
Diesel Fuel Supplement +Cetane Boost | Power Service
Maybe just change out both fuel filters as they can get clogged with wax crystals.
http://www.todaystrucking.com/images/SolvingWinterDieselProblems91-1R2.pdf
Hope this cures your problem.
