High temps can definitely slow things down. We will be over 100 for a few days in about a week.
Trichs are almost milky white. I harvest at milky white or just past but that is a personal preference. If you want more of a body focus let some turn amber. They go from sparkly, sugar dusted like diamonds, then milky white kinda like they are snow dusted, the kinda dull looking and lose that pop, then comes amber.
The bud below was harvested at milky white. As you can see there is still plenty of amber after curing.