The herbal constituents in pure neem oil are degraded over time by being subject to being "thawed" again and again. By which I mean going from a cool state (below 60F) where the oil solidifies to warmer temps where the oil liquefies. Storage at higher temps wouldn't be helpful but one day in summer heat doesn't undo potency. Far more important is pouring into batch size containers upon the initial warming to liquefy the seed oil and then storing those re-pours at a stable temperature below 60F until needed.