Interesting that the stats track that way.
I have always noticed (anecdotally at least) more suicide/attempt calls around major holidays, especially the winter ones. Family Disturbances shoot the roof right about now, but usually taper off by about 2000 hours on Christmas Eve.
I have worked suicides on Easter.
Mental health calls doubled around here in the months after 9-11.
We had a rush of disturbance calls and suicides/attempts following the bust; about six months after major layoffs at a local employer, when the unemployment benefits ran out.
For disturbances, the most violent and busy nights I have ever worked were Valentines Day.
If you get familar with this stuff, you can gain a measure of predictive ability and be proactive about this stuff, reinforcing your line officers and making sure that the right resources are available. Just my experience, at least.