Kineo Kid,
I did a southbound hike in 2002 from Mt. Katahdin to the NY/Conn. state line starting the last week of August. What I chose to do was go over the Whites from Pinkham Notch to Franconia Notch at the beginning of my hike, precisely to avoid having to go over the above-treeline stretches in October. I then moved north and hiked south from Katahdin. I got back to Pinkham Notch on Oct. 9 and the weather was already cold – the night of Oct. 8 was below freezing and it didn’t get much above 40 degrees along the Moriah/Carter/Wildcat ridge on the 8th or the 9th. It would not have been pleasant above treeline – and this was relatively benign weather. There was no snow visible on Mt. Washington, but there had apparently been several snowstorms already. I ran into rime ice and below-freezing temperatures going over the summit of Moosilauke on Columbus Day but otherwise got through the rest of the Whites without incident
I’m glad I chose to handle it the way I did – it seemed to me that some of the other southbounders I was meeting up with were pretty naive about being able to get over the above-treeline stretches that time of year without extra gear, winter camping experience, increased risk etc. You also have to remember that the Madison Spring and Lake of the Cloud huts close in mid-September, so that makes a Presidential Range traverse that much more technically challenging.
I should say that overall the weather on my hike was great for hiking. Just as long as you’re equipped for cold rainy weather in October, you’ll be fine.
Check out my hike web site at http://users.rcn.com/rickbb for my journal and photos. It’s got temperatures and weather information.
Snowbird
Snowbird