Here in San Diego, the strange weather is messing with our lychee trees. It was cool in late fall and early winter but then it was really warm the last month. Now it is cooling down again and starting to feel like winter.
My lychee tree was leafing out for the last couple of months with new leaves still forming while other leaves were starting to harden off. When the cooler weather hit, the new leaves started to shrivel up and then flower buds started to develope.
I guess here in San Diego where growth is much slower, the current vegetative flush does not need to harden off before a bloom. Perhaps the slower growth allows the tree to build up enough energy reserves to allow for flower panicle developement. This same thing happened to my lychee tree last year.
Here are some pics of my tree showing leaves that have not hardened off with leaf die back on the youngest growth and the beginnings of panicle formation on some of the older growth.