At what temperature does jet fuel freeze at?

Jet A fuel, the most common type of jet fuel freezes at −40 °C (-40°F)

However the problem does not arise in practice as most modern jet aircraft are equipped with in-pipeline fuel heaters which maintain the temperature of the fuel lines so as to prevent any gelling or freezing of the fuel. Indeed, a much more concerning phenomena is the freezing of water-ice crystals in the fuel, as water has a much higher freezing point, and can clog fuel lines. Nowadays almost all jet fuel is treated with special additives which, among other things, prevent the formation of these ice crystals.