I've been experiencing this issue for a while now.

everyday, starting from around 3pm, LoL becomes literally UNPLAYABLE. (this problem always existed except for the previous week, where it seemed "fixed").

even if my latency is close to 100ms, i experience up to 9 seconds of DELAY/LAG in game.

How to fix this? although i doubt i can do anything to fix it, because it seems its on Riot's end, im open for solutions.

Symptoms:

no lag at the pvp.net client at all
no lag at the champ select screen
loads fine
once im ingame, i buy the 1st items, i notice 0 lag
then after a few minutes the lagfest begins
sometimes i alt f4 to attempt a reconnect
most of the times it gets stuck at the LeagueOfLegends logo right before hitting the load screen
it gives me a firewall w/e error (i use no FW at all)
i got to CLOSE the client and reopen it
but ofcourse, when i lag, theres no fix for it: even after reconnecting, the lag will keep going.

so, i dont know what to do. over 5 of my 8 left games were caused because of this.

by the way, i can play just FINE in the morning.

any solutions riot? (will keep this bumped).

What ISP are you on? It's possible that at certain times of the day (peak times, early evenings) your ISP is throttling your connection.

.

okay, its a wireless nextel modem.

Specific time based lag, especially at peak times tend to be issues with your internet connection. You may want to try running a netalyzr scan while you're experiencing a slowdown, but most likely you would have to contact your ISP to resolve this issue.

...but my latency is OK while the slowdown happens

i can run other games fine aswell

Which makes sense until you look at the alternative, which is that instead of your line having issues around that time, the backbone or incoming server line to Riot from your location is overcrowded and causing lag. Since we haven't gotten any major reports of outages like that, it does seem like the issue is probably on your end if the problem seems to be primarily time-based.