I can't see how it can physically be done unless your thermometers are out.
We don't even get temperatures that low here where i live at night let alone in the daytime.
I try to clean in low temps. Once it gets to -4 or -5 then the brush is like a rock even if you keep the jets clear,
ice is forming on the glass and the sills freeze up within seconds.
Any water hitting the ground freezes and the pole jams up. At some point you have to shut the flow off
this is when your kit freezes.
At -14 0r -20 your tank will be freezing over, even diesel starts to gel at those temperatures.
ps. Ice doesn't dry on the glass so how you know the glass is clean is amazing