Mosquitos? In the Afternoon?

I had my time in and left work early today.  I was prepared, and went to the store for my weekly grocery shopping.  So, about 2:30 in the afternoon, I was leaving Wal-Mart and decided I had an itch near my right elbow.  Not just an itch. I had a mosquito bite!  What is this with a mosquito in the afternoon?  I don't know. But, it still itches some 5 hours later!