I submitted my primary on the day AMCAS opened, prewrote my secondaries, and submitted them within 24 hours of receiving them. I started getting IIs in early to mid July, and got them pretty regularly until late August. After that, only a few more trickled in, with the last one arriving in mid-October. My interviews themselves were very heavily centered in September and mid-October, with a few more interviews in mid to late November.
I had 14 interviews, and missed ~25 days of school this semester due to interviews and travelling. I live on the West Coast and the vast majority of my interviews were on the East Coast, so each trip took me 2-3 days (full day of flying, full day of interviewing the next day, full day of flying the day after that). I tried to make sure one of the travel days was on a weekend, but I still ended up missing two full days of school for most of my trips. Like I mentioned, September and October were my busy months. For almost 6 weeks, I had 2 interviews per week, so I only attended one day of school each week for the first half of the semester. I think I attended three full weeks of school during the entire semester because I had a few other interviews in November as well.
I am SO grateful for the opportunities and experiences I've had, but it was very challenging to keep up with schoolwork. Make sure you're prepared, because I certainly was not!