You mention that "In the cold the rifle slam fires. If I bring it in and it warms up it functions like it should". If It were my trigger, I would clean it thoroughly with lighter fluid to remove all oil and other contaminants that might be present.
Since cold weather might be a factor as you stated, there could be some oil in the mechanism that is hardening/becoming more viscous with colder temperatures. I would try that before I sent it off to Timney.
