Ammm....
While reading this thread I was seriously dazzled not about the oils different people are using but the shere fact that somebody actually drives close to 0 degrees of C...
I live in a nordic country and I shoved my bike into the garage when it fell below 10deg of C. I have not been riding for 2,5 months now and it still is above 0 most of the time (very warm winter for us).
Maybe I should get my bike back out again

You guys are either wearing 3 woolen jumpers, have installed heated grips + jacket or get a very warm backrub from your missises before the runout.
But wow.
To the topic. Not knowing exactly about the oils I put 20w50 in there since the summer was hot and close to 30 deg of C for periods of time. I looked at the chart and changed from 10w40 to 20w50. Is the beforementioned oil still good at higher twentis of C in your experience?