Geranium blossom dying
I can't be sure what's happening here, but from your description I do wonder about flower stress due to the dry winds in your area. The wind could simply be drying out the center petals of the flower. As far as watering goes, make sure your plants are in a good quality potting soil (if they are still in their nursery pots, repot them) and in a pot that allows them some room for their roots to grow. I would also consider adding a mulch to the top of each pot to help preserve soil moisture. The soil surface should feel slightly moist to the touch, but not wet or too dry. Again, I can't be sure of what's happening, but I think your plants need to get more established in their new environment and protected from high winds and drying out. They also need full sun (at least 6 to 8 hours a day).