I think the main thing you need to think about is being prepared: for cold and wet.  Heavy duty or extra sleeping bag; good raingear, good food; particularly into October.

starwatchr

part of the Q?  any.
max leaf color?  3rd week Sept-1st wk Oct  +/- few days
weather?   all of the above
temps?  daytimes 40-70's   nightimes teens-30's
moose behavior?  not a concern
water levels?  usually lower, creeks may depend on fall precip

end Sept-1st week Oct is the "prime" time IMO

Our group has been going into the Q or BWCA for about 11-12 yrs now.  Usually we have gone the 10 days that cross over the end of May and beginning of June.

As I will be welcoming a new paddler into the world around that time this year, we have a very good excuse to wait until the fall this year (waiting will be the hardest part).

The typical  weather will not be a big driver in the planning of when, we just need to get a feel for what to expect relative to the "when".

• Leaf colors max
  temps
  water levels (are creeks OK then)
  more likely to be windy (avoid a lot of the bigger lakes)
  is moose behavior a concern, etc.
  typically rainy, snowy, sunny, all of the above?

So, gang, when and what part of Quetico would you suggest?

Cheers,

FYI, we like to come in from the north, as we "Paddle the Dream".