Terpenoids boil away at very low temperatures. It could easily get over 100 in a car in direct sun (farenheit). You will lose the terpenoid content first & the added heat will begin to cause the equilibrium shift towards the degradation products of CBD, etc. That is non reversible. The longer it "cooks" & the hotter the temperature, the worse the effects. It will probably be a harsh tasteless hit. How much it affects the CBD content is variable.
UV rays will degrade the quality of the oil. I would keep it out of direct sunlight for long periods of time. If you have a water soluble definitely keep it out of the hot sun... on that note the heat will not affect the oil.
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