You can see both overall speeds and speeds at a particular event. If you look at a player's profile it gives you the speeds for the entire class at the top. If you go down to a particular event the player pitched in, you can see the numbers for just that event.
Average speed for pitchers at this year's WWBA for 2017's was 80 mph.
That's pretty much in line with what I would expect. "Hard" throwers I saw this summer (16U) were usually around 85. I only saw a few 90 throwers - and those were usually in 18U events.
The average person hears 80mph and thinks it's "slow", when in reality there is only a small percentage of humans in this world capable of throwing that hard - let alone 90 mph.
After my son closed a game this past spring - 3K's on 11 pitches - I had one of the opposing team parents come up and tell me "that kid" was probably sitting in the high 80's because these batters just eat up kids throwing 80-85.
I was like yea - um no. Pretty sure that kid isn't sitting anywhere near high 80's buddy.