My dad and I are driving a friend’s 5th-wheel trailer from Missouri to Anchorage and flying home. I’d like to leave in early September; what kind of weather are we likely to hit?
Are you sure you can even make this drive? I remember a while ago looking into driving to Alaska and to reach Anchorage (or maybe it was Nome) you had to take a ferry.
I don’t remember now, but I do remember the idea died pretty quickly between my friend and I after we realized there was no direct route. We were in No. Calif. at the time, and this was a number of years ago.
I’m off to mapquest. Please ignore my post! 
I’m back! Apparently, you can do it. Holy Jeebus, that’s a long drive. I hope you and your dad like each other.
I did the ALCAN in late October, and hit snow and ice a few places. At least now the road is paved all the way. Early September ought to be fine. You’ll hit some rainy places, but overall it ought to be clear and cool.
It’s impossible to predict the weather in the northern sections of the highway, although September should be okay. August is generally the wettest month, but that could extend into September. We’ve been having a fairly cool summer this year, despite predictions of ‘warmer than usual’. You’ll be driving in the fall colors, which will be beautiful. Order yourself a copy of The Milepost right away. This is a comprehensive guide of not only the Alcan (which ends in Fairbanks - or Delta Junction, depending on who you talk to), but also all Alaska highways, including the Glen Highway (which takes you from Tok Junction to Anchorage). You could probably pick up an older version on ebay, cheap. I highly recommend spending one of your nights at Kluane Lake campground. This is located north of Haines Junction in the Yukon Territory and is a beautiful spot.
I’ve run into snow that early in the mountains, but it’s not likely.
The Alaska highway runs through my home town in northern Alberta. It’s kind of funny because there are street signs to the effect of “City Centre - turn right, Alaska - go straight.”
(Alaska is over 2000 km away.)
I know this isn’t relevant, other than demonstrating the existance of the highway, but maybe you will find it amusing.
As I understand it, the majority of “mainland” Alaska urban areas are accessible by road from the Lower 48 and Canada via the Alcan Highway. Chefguy outlines the main route to Anchorage.
There are, however, some areas that have local roads which do not have connections to the rest of the highway grid. Nome is the obvious example; there are several roads connecting nearby outlying settlements to Nome, but none of them connect through to Fairbanks, Anchorage, or any of the other substantial communities. It’s my understanding that there are quite a few similar places in the Panhandle, a couple of which connect into B.C. but most of which don’t have thru connections to the North American highway grid. Someone who’s actually familiar with that area, though, would have to address this.
Only three towns in Southeast connect to any sort of road system: Hyder, Haines and Skagway. All others, including the capital, Juneau, can only be reached via ferry or air. There are no major coastal Native communities that can be reached via road, unless you include Klukwan (a Tlingit village near Haines). This includes Nome, Kotzebue, Bethel and Barrow.
The Donner party left Mosouri in August.
Just sayin’, ya know.
Tris
I’ll second Chefguy’s suggestion of The Milepost. Coordinate it with radio weather broadcasts and ample provisions and you should have a pleasant trip. I drove from Dallas to Anchorage in March with no problems and back in late December to early January. Even with snow covered roads, if you’ve got 4 wheel drive you’re probably okay (and this was back before it was all paved.)
I’m thinkin’ I remember Anchorage getting first snows in early October or so. Chef, is that right?
Well, I like on the Alaska Highway, though on the southernmost section of it in Northern B.C, still about 1500 miles short of Anchorage. Mid-september is a pretty nice time of year for driving up here. All the trees are turning pretty colours, and usually the frost isn’t really bad yet on the roads. It’s a bit of a bad time for wildlife though, the deer and moose seem to be all over the roads, so you want to keep your eyes open, and try to avoid a lost of driving around dusk.
Keep in mind though that the weather can be fairly unpredictable. Make sure you’ve got blankets and other emergency gear when you’re travelling. You shouldn’t need snow chains yet, but I would still plan on having them. Snow that sticks around usually falls somewhere in october, though a freak fall that melts the same day can happen anywhere from september onwards, and will fall heavier in the mountains.
Can’t tell you anything past the border, the furthest up I’ve even been is Skagway, which is pretty close to the border. I was pretty young when we made that drive, so all I really recall is that the country up there though is pretty amazing, and bring lots and lots of bug repellant.
You’re from GP, right? 
Technically, the it’s not the Alaska Highway untill you get to Dawson Creek, which is in B.C. I’ve seen that sign, and that pointing out highway 43, which connects to the Alaska Highway.
On preview, I’ll pretty much echo what Chefguy says, other than the colder summer than normal. In my part of the country, it’s been way hotter than normal. Of course, that doesn’t mean much, since the weather can and does change on a moments notice.
Anchorage always had snow on the ground for Halloween. It would start flurrying a few weeks before, but Trick or Treating was always done on snowy streets.
You bet! 
Cool.
Yeah, somewhere around early to mid October is about right.