hmm. I broke my Water Fasts in the evening. I'd never even thought of that until you asked--but the interesting thing is, I've never been a breakfast eater, and now what I generally prefer is to eat one meal a day -- that one is usually in the evening. My body tells me I'm better with less food. (could be partly age as well) Breaking in the evening makes sense then, for me. Some people might be very much 'morning people' though. Or, lunch types. I would say, go with what your own body tells you.
Mot of all, don't be a slave to the idea of three meals a day.
The other reason maybe to break in the evening would be that one is waiting through a day to see that true hunger is increasing, or, to notice there is a sufficient window of feeling 'up' to warrant breaking. On the other hand, if you're a person who likes to sleep on things to see how they look in the morning, morning might be good! :-)