We are debating about what sleeping bags to take for a June 9 departure from Jamestown for the transam. What kind of temps can we expect and where?

We all own 55 degree REI bags that work great for Summer camping. They work pretty well down to 40 if you pile all of your clothes on top of yourself in the bag. It is a real joy to carry only the tiny bags if it is warm enough. We all own some kind of warmer bag as well.

Would a pile liner add more weight than makes sense? Silk?

If there is just a chance of freezing a couple days out of the whole trip maybe an impromptu vapor barrier from trash bags bought locally? Or just get a room if it is colder only a few days?

How cold do we need to plan for and on which sections. It would be nice to have the minimum required for a given section and maybe have something warmer shipped if the place it would be needed was predictable enough. Or do we need to bike the bullet and carry a 30 degree bag?

Pete

I would say that, for most of the country, a very light bag will do nicely...especially for a June start. The place where you'll likely have problems will be in Colorado. West of Pueblo you start into real mountains where the summer temperatures can dip below freezing, depending on cold fronts. Wyoming and Montana are going to have similar temperatures, although not as extreme.

My suggestion would be to carry the 55 degree bag and look for a liner when you get to Pueblo. You could rent a car in Pueblo and drive up to Colorado Springs (about 45 mile north to the REI), if you can't find anything in Pueblo. That way you don't have to huck something of limited use for 2000 miles.

So that the whole trip wouldn't be wasted, you could also go visit Pike's Peak (hint: it's that mountain you see to your right and you've been seeing it since about Eads ). Worth the side trip. If you don't want to drive to the top, there's a cog railway in Manitou Springs that's worth the money too.

A summer bag will probably be ok, but I always like to have the option of sleeping in colder weather than I expect....ie be prepared, so ou have a few options.

1) supplement your existing summer bag with an adventure medical bivy bag

https://www.amazon.com/Thermo-Lite-Bi.../dp/B000NK4L66

This really helps cut out cold winds....its far better than a cotton or silk liner and weighs about the same, its also useful in an emergency.

2) You could just buy one of the new light weight 3 season bags from someone like Western Mountaineering

https://www.westernmountaineering.com...2&ContentId=16

of course that is quite expensive.

3) you could also just wear some insulating clothes. If you don't have a thermolite vest or jacket think about getting one as they are good for chilly nights in camp and can be worn inside your bag on cold nights.

My personal sleeping system is a combo of a Prolite 3 sleeping mat and a jacks r better summer quilt as I don't like being confined. This combo is good to 45F. If it dips below 45F I put the mat and the quilt inside the adventure medical bivy. This gets me down to 32F. If it gets colder I'll strap the quilt around the mat to seal in more body heat and put on my thermolite jacket.

Prolite mat = 20 oz
Quilt = 15 oz
Bivy = 6 oz
Montbel Thremolite jacket = 11 oz

I should think that, up until you get to the Rockies, you can survive a cold snap by either:

1. Putting all your clothes on, including rain gear (vapor barrier) and crawling into your sleeping bag.

2. Getting a motel room for the night.

Chances are once you get past the Appalachians, you'll be looking for cool breezes more than warm bags.

When you get to Pueblo, you certainly could get whatever you need to get through the mountains. Afterward, you can mail home whatever you don't need.

I think this is exactly right, and you won't have any problem finding a fleece liner in Pueblo. Or buy one now and have someone mail it to you there. With a June start you will be fighting some hot nights, try a coolmax or silk liner as your sleeping bag for those nights, it's actually cooler that sleeping without anything, wicks away moisture.

To give you some idea of the temperature differences, in June and July, the average high and low in Dodge City, KS is 90F and 60F, respectively. For Pueblo, it's about the same. For Breckenridge, CO, it's 70F and 39F, respectively (135 miles away). For Steamboat, it's 76 F and 45. You'll probably find similar temps all the way to Missoula.

One thing to remember is that from Pueblo to Breckenridge, you have to cross South Park. South Park is a hole compared to the mountains around it, and the temperature can fall even further. About the only other place you'll need a warm bag is when you get to Astoria. That's one cold place!

Its a long ride, you can always buy a warmer bag once you hit the mountains, you may find a fleece is a cheap way to add warmth once you hit the mountains in the west. Have a good trip. We are having the same dilema this year, starting in Montreal, where I think it will be hot and humid, then going east and north till we end in NFL. where I suspect it will be damp and cold. I think we will go with the cheap fleece and if necessary get some bags from the REI or MEC and shipped general delivery.

Another option is that if your warmer sleeping bags do not have the side baffles, you could just shake the down to the bottom on warmer nights and to the top on cooler nights. This has worked very well for me (using a 20 degree bag) even in the nights where the temps are in the 80s (all down is on bottom). As to whether you will be cold, it is definately possible. I got snowed on July 4th in Yellowstone (low was 27 I think), yet a few riding days later I hit 92 degrees east of the divide in Dubois, WY. But the memories !

I'm leaving on the same route from virginia around May 19th. I'm bringing a Marmot Pounder - 1 lb synthetic 40 degree bag along with a SeatoSummit Reactor liner which can add about 8- 15 degrees to your bags warmth weighs 9 oz and keeps your sleeping bag much cleaner, it also doubles as an extremely warm weather bag on its own.. I'm also bringing my Mountain Hardware Phantom Jacket a 14oz 800 fill down jacket that fits inside a nalgene bottle. all of that stuff is just under 3 lbs and should be enough to light me on fire if it gets really rough in the mountains.
edit*-Forgot the Prolite 4 thermarest sleeping pad.

What's your schedule looking like, maybe our groups will bump into one another?