Lots of good talk about temperatures. Please let me add a thought to the mix. This is not a deal of magic thresholds, that is 'no THC before XX degrees, then you get it all'. Consider water boils at 212F but a rain puddle evaporates on a 70 degree day. Boiling point is just the place where (at that pressure) no liquid water exists, it's all going to be steam (vapor) but the time it makes 213F.
There's actually formulas for this, giving partial pressures in mm of Mercury (760mm being normal atmospheric pressure, give or take, as the weather channel reports). At room temperature this is a few mm IIRC for water. If the air is 'dry' (there's less than that pressure already there, evaporation happens since water molecules leave the puddle faster than they condense out. Get past that (like when temperature drops) and you go pass 100% Relative Humidity and you get fog. Heat the water enough and the partial pressure number reaches 760mm and boiling happens. This is the physics definition of boiling in fact, when partial pressure equals chamber pressure you're boiling. Freeze drying works this way too in a fun way by reducing the vessel pressure so the vapor pressure of the ice is higher.
So THC has a vapor pressure near 760mm at about 390F. It 'boils' then. It all wants to be vapor above that unless you raise the pressure in the room.
This is also why stuff cooks slower in Denver. A 3 minute egg is really soft there because the pressure is lower 'a mile high' and therefore the boiling water is less than 212F. In Death Valley it would be modestly higher than at sea level. In a steam boiler, as the pressure builds the boiling point goes up which is how you can have liquid water in a boiler above 212F.
The other way to look at it is saturation. Fog means the air is holding more water than it can (so the excess comes out as floating water drops), the air is saturated with water vapor. Clouds are the same thing, only up there (where it's cold), rather than down here (where it's warm). Likewise our vapor has a saturation number based on temperature (never seen it listed, has anyone?). This situation is what the cloud chasers chase.
So you're getting at least some of the good stuff way under 'the magic temperature'. The rate may be low, but it's there. Like the drying rain puddle. Heat your bud to say 300F long enough and you'll have none left without ever making it to 390F.
To use a really bad pun, 'it's a matter of degrees"?
OF