waves

Wave activity on Erie is totally dependent on the wind speed and direction on any given day.  It can change from morning to afternoon from flat to 6 footers or visa/versa.  For near shore fishing you are going to need south winds usually, maybe East or West will be doable but it depends on what shoreline features you are near to provide protection.
No particular 'time of year' can provide you a sure bet on fishable waters, you have to watch forecasts for wind speed and direction and you will also need to learn to watch the previous 3-5 days history of rain, wind and wave directions to get an idea if water clarity will be a factor.   
There are numerous government and weather sites for wind/wave forecasts and even a camera on an off shore buoy for more 'real time' conditions.

Depending on the time of year and what and/or the species of bass you're after the Bay can be a pleasant place to fish for bass with unusually good results. Large mouth are available all year round with an infusion of bedding smallmouth during late April, May and June. The Bay is a lot calmer and offers some well rounded fishing not just for bass, but for panfish, northerns, perch, musky, an occasional walleye, along with cats, carp and even bowfin. Great place to drown some bait with youngsters.

walcat
 Said" I ain't never going on that lake again." Two weeks later he was in my boat fishing for smallmouth. Did get another new boat.

I am glad your friend was OK, the lake is very unforgiving!   But it is also an addictive thing...   It just wouldn't seem natural now to NOT go out on the lake nearly every weekend through the summer season... it just draws you back.

I fished the PA State Team tournament that had about a half dozen boats capsize on the first day. It was flat in the morning at take off. By early morning it started to get bad. I was all the way to the NY line. What took less than 20 minutes in the morning took almost five hours to get back.

I was sure we were going to die out there when I started back. At some point we got far enough that I figured we would live, but lose the boat. A little further along I figured we would make it back, but probably lose the trolling motor, seats, and electronics. Once past McCord's I knew we would be okay and we were.

It was hard on the throttle to stand it up on end as the wave approached, throttle back at the top to not flip backwards, on the throttle coming down to not stuff the nose into the next wave at the bottom, rinse, repeat for hours.

They restricted us to the Bay the second day.

My experience was prior to the Northeast harbor. Basically there was a little ramp and boat lift there and nothing from there to the Bay.

A guy in our club actually tried to use the boat lift tgat dsy and their power went out. A wave swamped it right on the lift.