Quality of games and time of day
So here is my Story.
About a month/Month and a half ago I wanted to push number of games to see if my 53% win rate top lane would actually let me climb. My schedule made it so my most free time was 6pm-4am PST so did most of my play then. I would play 3+ games at a time and as many as 6.
Result: I went from S1 Promos to Almost demoted to B1 I played Urgot and Illaoi top with Panth after Rework and a mix of a Malz/Swain/Reksai mid (Reksai mid counters Zed and Yasuo at least for me)
My games were 90% full of VERY bad toxic players who often afk. I had zero control over most anything in a match because I would get 1 other player that knew what was going on and had a clue how to play. 2v8 games are 99% unwinnable. This was basically every game. My Tilt and frustration with the game went through the root after 3 games. I found that most players at this time are not even NA players. They would have pings in the 150+ range.
I the went on vacation and since I came back I changed when I would play. 11am-3pm PST
So far I have blazed through S4 and won Promos to S3 with little effort. My teams are less toxic and have way more skill. Understanding of what you would expect from Silver players. Less crazy champ picks (Zed jungle, Teemo ADC) and its now more 3+ players have a clue what to do in a match.
Im playing the SAME champs the SAME way but have a 70% win rate over last 20 games vs 30% like I was having. I also have some control over a match with people listening to Pings and following up on Jungle fights.
I know I have gold skill as I have been to S1 Promos literally 30+ times but I have always played at least 50% of my games in the late night.
Time of Day (at least from my experience) maters 100% on quality of games. Riot really needs to address that.