Why do my plants smell more some days?

[Dark Matter]

I have 2 NL plants flowering for 5 weeks now. Yesterday they had a very strong dank smell (nice) and today they hardly smell at all...whats the deal with that?

 

[Weed420]

Usually its the heat levels that will make it more stinky.

 

[OldSkoool]

I've notice the same thing with my smelly bag seed lady. Although it can occur, off, and on during the day, not just one day to the next. My cab stays a pretty constant 75* - 78*, dipping to 60-65 during the dark hours. I thought heat might be the trigger, but after checking temps, I haven't a clue. Weed420 is pretty savy, he's probably right and I'm missing something.