The majority of the trips I have taken to BW have all been the week before or the week after Memorial Day.  I just like to use that "holiday" to stretch out my vacation a bit. For the most part "bugs" have not been a big issue.  It seems that we have been very fortunate to be "in" just before they get bad.

Quite frankly, however, I prefer it to be cooler than hotter.  The prefect weather for me is "50's" at night 60's during the day.  It seems that this time of year generally provides it.  So as the day warms up, some of the little biters might start to hatch, but you loose them at night.  that being said, I have had trips where it snowed and trips where is was miserable hot...sometimes in the same trip. 

Of the tips I have taken during various times of the year...I think that timeframe provides the best chance at good fishing and low bugs.

Hope you have a great time!