I can tell you first hand that Blue Dot acts crazy at 30*F or less. I built some full power loads in the summer and when I went to run some over the chronograph in December, and, yes, it was under 30*F here in Indiana then, and I was getting over 2100fps from my Marlin 1894.
Suffice it to say, that was the last I used the powder here in the great white north!