Originally Posted by alphatier
I doubt your highest monthly mean temperature is anywhere near 23C. 23C average high seems not unlikely though.
No, my monthly mean for the warmest month is 17.5C. The mean of the coldest month is -5.2C, so that makes a difference of almost 23C between the warmest and coldest month.
Read again, I never said that the mean in my warmest month would be 23C.