Blossom Drop

I think my tomato plants have blossom drop!

"Blossom-Drop is a condition suffered by tomatoes, peppers, snap beans, and some other fruiting vegetables where the plant blooms but fails to set fruit, the blooms die and fall off. It may be caused by the use of excess nitrogen fertilizers or dry windy conditions, but the most common cause is temperature extremes. Tomatoes, peppers and beans are especially picky about the air temps when it comes time to set fruit. If the night temps fall below 55 or rise above 75 or if the day temps are above 90, the pollen becomes tacky and non-viable. Pollination cannot occur. If the bloom isn't pollinated, the bloom dies and falls off." I-Village Garden Web

Here my guess is that it is the temperate swings.