My last two big episodes have happened in March, was recently tested and found that I have a vitamin D deficiency. I think the first episode which was Manic burned me out of Vitamin D and this year when I came around I got so depressed. The first one I was taking Endep which launched me into mania for 4 months, talk about a way to find out your bipolar. Pain in the arse
I definately have the 'March Madness' and I think the extra hours of sunlight really affect my body clock and I start to sleep later and wake as soon as it's light outside! I dread the winter as it has such a bad effect on my mood and I know at least 2 others that are the same, it's like SAD only I spring too high in the summer!
My hard time is usually starting in May and then lasting through the summer. I don't do well in the heat and the bright light can bother me for some reason. I think that I actually spend less time outside in the summer and try to avoid the sunlight more. It's weird.