The price went down leading up to the decision on SegWit (mid July) simply because MARKETS DO NOT LIKE UNCERTAINTY. Any time there is fear there will be panic selling. There were people who were convinced that Bitcoin was going to "break" or go down in price after the split so they sold during the height of the so called civil war.

Coincidentally when Bitcoin hit $1800 and wasn't nearly as profitable to mine as before, the miners began to signal for Segwit. This drove the price into a frenzied rally which landed us where we are at today. The price might actually begin to rally leading up to Oct.1st and then drop right before to allow one more chance to buy back in.

I'm fully expecting the alt-coin markets to take another massive hit right before and then recover sharply afterwards so set some good buy orders in low and make sure you shift your funds into BTC well before the split. I would start doing that this week to be honest :)

ALSO STOCK UP ON MORE BTC