Jet A has a fuel freeze point of -40C but this a conservative figure. Having operated flights on a regular basis over the North Pole from the USA we had actual fuel freeze analysis done during refueling prior to each trip. The results showed that we were always safe down to -45C at least. The problem is, as stated, fuel waxing, and even when the temperature increases again the fuel may not return to it's original state and so fuel flow may continue to be adversely affected.