Grand Teton Route Conditions Mid September

I'm planning on climbing the Grand Teton mid September this year.  I understand weather conditions are highly variable especially around this time.  If the route is in good condition (no snow or ice) and the temperature is not too frigid, I would like to do the Complete Exum.  However, I'm trying to get a sense of the other route conditions if we are to arrive after the first snowfall or any freezing rain.  It seems that the Upper Exum would be the route in the best shape since it is mostly in the sun as opposed to the OS which is mostly shaded.  Does anyone have any information as to how the Lower Exum or Petzoldt Ridge handles snow and/or ice, or what conditions one would expect these to be in mid September?

What conditions would one expect in mid-September? 

"Weather conditions are highly variable". I think you answered your own question  . Steep sun-exposed routes are more likely to clean up quickly, as you pointed out. Frigid temperatures? Bet on those if you define anything under 32°F as frigid (very balmy for many locals). I will add that easier to manage snow often falls on the upper mountain by mid-September and ice is more likely below 12,500', but "weather conditions are highly variable".

The big question is why wait till mid-September if you want to avoid ice and snow? That's a little like trying to avoid rain by going to Hawaii during the rainy season. Thousands of places to climb and you have already done the Lower Exum. Expand those horizons. My 2 cents. Either way, good luck with the weather.

Thanks for the input Teton Climber.  As you pointed out, I already climbed the Lower Exum but did not summit.  I'm not necessarily trying to avoid snow and ice, just trying to find the route that would give us the best opportunity to summit in mid September if conditions aren't optimal.  I guess I just want to summit after failing to do so once before I look to do a different mountain.  As far as why September, my climbing partner is climbing Denali in the spring and wants to wait until late summer/fall to take off again from work.

It depends is the obvious answer.  I just checked the dates on some old photos and an anecdotal data point in your favor is that in 2018 I guided the complete exum on September 7 a week or two after it snowed feet at the lower saddle.  My memory is that we had great (dry) conditions for the entire route.  It could be totally fine, but it could also easily be totally not fine.