Where were you when you last set the rigging tension?
I just did an online calculation thingy and it suggested your stainless-steel rigging could expand considerably in length between Maine (40F) and the tropics (80F).
I'm not sure of the decimal place, but a 60-foot length would become either .25 or 2.5 inches longer. I suspect it's .25 . . . or you would really notice it. But .25 is enough to make a big difference in the tension . . . a few turns on the turnbuckle.
I never thought about this before . . . but if you include the thermal effect on the mast as well, could be an issue. What is the bigger factor in the expansion of a carbon fiber spar? Carbon fiber or resin?
Is there a materials engineer in the house?