Pear Blossom, late april

I have spotted this effect the last few years and wanted to point it out. I have certainly heard it said a few times in permaculture circles about the importance of micro climate and I wondered if this was not a good example of it. This pear tree, where it is close too and protected by the granite wall, and enjoys the thermal mass and reflected heat from it is in full bloom. Where as the higher branches, above the top of the wall and thus more exposed are not even in leaf yet;