Unusual Number of Logins

I'm very new to LoL, but I've fallen in love with it. One thing I cannot stand though, is that every time I log in, no matter what time of day, PvP.net tells me they are having "An Unusual number of logins at the moment" and I have to wait 20 minutes to sign in. Hell, last night it took literally an hour and a half. The game is excellent, and I know it isn't a huge deal, but I guess I'm just wondering how Riot can call it an unusual number of logins if it happens every time I log in.