Hmmmm,

I don't see consulting charts as the solution...rather just another
data point. I choose to fly where most days the density altitude at
launch is somewhere between 10k'-12k'(Salida, Buena Vista, Leadville,
Telluride). I have never considered constructing a graph....not that
it might not help. I try to launch by 11am, downhill if possible, no
water if behind a Cub, plenty of water if behind a 260Pawnee, no mid
afternoon launches into strong thermal conditions. I like at least
7500' of runway. Pawnees are not great climbers at 70 knots, and I
have done my share of fence inspection tours grinding around low. I
accept the risk/reward by refusing to fly with water if I have any
doubts...and just a couple of degrees of temperature can make a huge
difference IMVHO.

Having flown in these conditions for the last 9 years, piloting and
fuel load affect the safety of the launch as much as POH climb
prediction. Ever towed behind a pilot who had not set the fuel
mixture correctly? Or did not stay down in ground effect to
accelerate? Or with a big guy at the stick who just topped off the
tanks?

I would be curious what the predicted climb rate for the Cessna
150/180 based at Telluride would be on a hot day...not sure I really
would want to know