July and August is the time to fish the BitterRoot. June is too early in the year.

Back to the topic.

Personally I do not believe your problem was with the temp. I believe your problem is with the humidity. Or to keep it simple. moisture.

I have noticed drastic problems with the so called "superpowders" with moisture. So I have went back to black. Problem is solved.

Let the other guys argue about an extra 100 fps, or which powder drills the absolute smallest hole in a paper target at 100 yards from a benchrest.

Personally I do not care about bench rests, or the ittsiest bittsiest smallest hole.

I care about good solid ignition 100% of the time. And in all conditions. And the answer to that is black powder, and a big lead bullet!! Pretty simple. Tom.