My Yuzu dropped half of its leaves today! After months of being at the ready with Christmas lights for the chance Arctic freeze, 
the damage comes from a too-hot deck (83F) in April! Got me thinking about other conceivable outcomes…spinach bolting when 6" high? onions going straight to flower?
The fact that it is 70F at 6pm is crazy. That’s a chance occurrence in the summer!
The thing is,the plant will probably be ready for the Summer heat,if it comes on gradually.We sometimes get these Spring heat spikes,that shocks younger ones.