Flower colour and the seasonal quality of light?

Each year when the blues really kick in, I wonder whether there is a relationship with the seasonal quality of light.  Here are some blues from the garden 6th May; from top left moving clockwise, Germander Speedwell, Bluebell, Slender Speedwell, Green Alkanet, Thyme-leaved Speedwell, Field Forget-me-not, Ground-Ivy, Wood Forget-me-not, centre Grape Hyacinth.  All are wild or naturalised in the garden except the Grape Hyacinth which is in a pot:

This was followed closely by the pinks, 8th May; clockwise from top left Bush Vetch and Red Clover, three geraniums Dove's-foot Crane's-bill, Herb-Robert and Shining Crane's-bill, then Red Campion, Cuckooflower, Red Dead-nettle and centre Crab Apple blossom.  All common native species, in the garden or yard:

And then the whites and more yellows after the earlier Primroses and Cowslips, start coming, more or less simultaneously.  These collections were taken this week, 21st May.  There were also a fair few white umbellifers (Apiaceae) not included here.  Clockwise from top left Bramble, Common Mouse-ear, Bogbean, Hedge Mustard, Wild Rasp, Bog Stitchwort, Cleavers, Oxeye Daisy, centre Heath Bedstraw:

And the yellows;  clockwise from top left again, Yellow Rattle (I just love the tiny violet teeth), Yellow Archangel, Meadow Buttercup, Kingcup, Yellow Pimpernel, Bird's-foot Trefoil, Wood Avens, Hop Trefoil, centre Tormentil:

Is it just what I happen to be seeing around here, or has anyone else noticed a seasonal pattern of changing colours? Admittedly from now it becomes a riot of colours, but later in the summer the deeper pinks and purples become more prevalent.