I have a solo trip planned for mid September 2019. I have a 20 degree and a 35 degree bag. Both mummy style. The 35 degree bag is 2 lbs lighter (and nicer) and packs much smaller. I have yet to test the 35 degree bag in cooler temps so I am hoping for input. Obviously I will check the weather before I go so I can adjust last minute. I will have warm clothes I dont mind sleeping in either so Im thinking I could get away with the lighter bag assuming avg lows in the 40s? Just looking for others experience on this. Thanks in advance!

Take the 20 degree bag!

It got down to 25 degrees one night last year the last week of Sept.

Take the warmer bag. It's not the average temp, but the low temp you have to worry about. It may very well get into the 20's.

Do you have a warm pad? You could of course sleep in your clothes too.

Since you haven't slept in the 35 bag, are they both EN tested bags for comparison?

20

Absolutely the 20. Could be a long cold trip otherwise.

Boonie asked the most important question. If you have a well insulated pad (Think Exped 9) you could risk the lighter better bag. If you're sleeping on a standard pad (insulated or uninsulated) I wouldn't risk it. Its always possible to boost the warmth of your bag by wearing extra clothes or wadding them on top of you in the bag- keeping the cold out from underneath is almost impossible without a decent bag or a well insulated pad. Ratings are arbitrary at best (even the EN ratings). Let the two bags lay out on your bed side by side for an hour or two and note the difference in their loft. That will tell you more than just about anything else. Roughly the same thickness roughly the same capability regardless of the claims of the manufacturer.

This is a hard call being that you give very little specific info. When in September exactly are you going? How long is your trip? What is the quality of the 35' bag vs the 20'? I ask about dates of trip because, lets just take last year for an example. Up to and including Sept 16th It was hot for September up north. On Sept 16 it was in the low 80's. On Sept. 17th it didn't hit 60'. And as the month went on it got cooler, the sun rarely appeared and it rained almost, if not every day. Except it snowed 3 times on the 28th. Of course this year will be totally different, probably, but the weather can change overnight is my point. So my question is are you going like Sept 10-13, or are you going Sept 12-22. If you are going for no more than say 3-4 days you could base your choice on the forecast. Anything longer than that and I would be hesitant to do so.

I have taken a 30' bag on all my September trips, 10 of them, and have never been cold at night in Sept but I also bring a small Fleece blanket that fits in my sleeping bag stuff sack. I am a hot sleeper too. You should also consider if you are cold or hot sleeper in your decision. And your bag is an untested 35' bag.

If it were me I would go with the 20' bag vs the untested 35' bag and not knowing what the weather will be like in 1.5 months. 2 lbs isn't that much to insure you get a good night sleep no matter what mother nature throws at you. In my mind I want to do whatever I can to not have to end my trip early. You have plenty of time to decide though.

I like to er on the side of too warm. You can always vent or unzip completely and use as a quilt. Mid September weather could throw anything at you.

Take a new and lighter 20 degree bag or quilt! My 10 degree quilt weighs 24 ounces in XLong & Wide. So toasty when cold.

But as others have pointed out...an appropriate pad is really critical.

walllee: "Take the 20 degree bag! "

I pretty much agree. A 20° bag means you will not die at 20°. You will not be comfortable. Take sleeping bag liner and if it is warmer than expected, just sleep in the liner. If colder then sleep in both.

minnmike: " ...lets just take last year for an example. Up to and including Sept 16th It was hot for September up north. On Sept 16 it was in the low 80's...
"

And I quote "Mike, when does it get cold around here?"
Mike: "Tomorrow!"

Prescient, n'cest pas?

I agree with everyone that your pad is equally important as your bag, many people don't realize this.

I'll be the voice of dissent. If the forecast isn't looking too cool take the 35. With the 2# weight savings you could bring a nice puffy jacket or layers you might not otherwise take and stay toasty if its a reasonably rated/well built bag. Then again I was on the Sioux Hustler Trail last September when it was sleeting/snowing and I wasn't upset I brought my 20 degree bag (my only bag at the time-but have since picked up a 30 degree quilt):)

You could also consider White Wolf's recent post about the record low of 37 . . .

What would be a record low on the dates of your trip? ;)

I would take the 20.

I always take my poncho liner (aka woobie) and if warm use that on top of bag. If cold, I have another layer.

Keep an eye on the weather up to you leave, but the 35 should be appropriate especially if you pack clothes just for sleeping, like long sleeve shirt, wool socks and light stocking cap. Stuff that should already be on your list.

In the end if you are anything like me you probably already made up your mind. You just wanted people to reinforce your decision. The people that didn't have flawed thought processes. I say this with a smile on my face if you don't recognize the humor/truth.

minnmike: " In the end if you are anything like me you probably already made up your mind. You just wanted people to reinforce your decision. The people that didn't have flawed thought processes. I say this with a smile on my face if you don't recognize the humor/truth."

Haha!

I have taken many September trips. I've had it be 25 at night and 80 in the day and you just never know.

I'm with tg, a 35 degree bag may work out well. It should be tried as much as possible ahead of time to confirm it's rating,. even if EN everyone's comfort range can differ.
I use a 35 BA Horsethief rated at non-EN 35 degrees F. I have comfortably used in to the 20 degree range, and have confidence in it. Matted with a 60 inch Exped L5 it is my go to shoulder season bag.

butthead

walllee: "Take the 20 degree bag! "

+1 - subject to last minute weather forecast prior to your trip

another vote for the 20

I tend to be hot when I sleep so I would take the 35, and if I do get cold I just put on a warm hat, while my husband is always cold and would want the 20. A lot depends on your own metabolism.

In September I would go 20 degree without even hesitating.

From a backpacker's perspective: Take the 35* bag. Your bag rating doesn't need to match the lowest expected temp. It should keep you warm even if inside your shelter temps reach a few degrees below your bag rating. Additionally, consider the insulating factor of your primary shelter. Are you cowboy camping or will you likely be sleeping inside a tent? It will be warmer inside your tent than outside ambient temps by several degrees. Finally, if you find there is a night that is extremely chilly, add a long sleeved shirt or toss a jacket over top of yourself, maybe pack a light down vest.

Why carry a 20* bag and extra weight in September? Save the 20* bag for dates nearer to or after the lakes ice over.

From a Solo canoer's perspective: See above.

From a group canoer's perspective: See above.

Enjoy your trip

I don't understand how anyone can tell you which one to take when your trip is some 45 days away. Its not like you have to pack your bags today. You could have nights in the teens or the 50's as far as anyone knows now. 2 days before your trip, you will have a much better idea of the likely low temps. Actual low temps you encounter will vary from the forecast, but not by much.

In addition to what some have mentioned (sleeping pad, your metabolism, etc) I'll add that my tent seems to hold at least 5º and maybe 10º above outside temps.

Thanks for every ones input. My trip is 9/14-9/21. I will be sleeping in a 2 person tent. My pad is an inflatable, no name brand. I will probably just take the 20 to be safe. Considered the 35 and a fleece liner but that starts to offset the weight advantage and packing space advantage. Thanks again.

SlowTroller: "Thanks for every ones input. My trip is 9/14-9/21. I will be sleeping in a 2 person tent. My pad is an inflatable, no name brand. I will probably just take the 20 to be safe. Considered the 35 and a fleece liner but that starts to offset the weight advantage and packing space advantage. Thanks again."

If I were you I would check into whether your pad is insulated. You can lose a ton of heat to the ground even in Summer like conditions. Maybe look into an insulated pad or borrow one if need be. Been there done that!

walllee: "Take the 20 degree bag! "

Lol, yep!

pilot: "

walllee: "Take the 20 degree bag! "

Lol, yep!"

I agree... I was glad on my forty day trip I had a good pad and a 20 degree bag. I had many frosty nights... I came out the 28th. Around the 20th I was windbound on Lac LaCroix and the morning I could take off it was 18 degrees. Even with paddling gloves I blew on my hands a lot. Haha.

I'll be headed in solo same week. What's your EP?

Yes I agree with everyone on the pad. Even with a 20 degree bag if your pad in not insulated you will get cold at night. A sleeping bag does not insulate you from the ground no matter what it's rating is.

minnmike: " Yes I agree with everyone on the pad. Even with a 20 degree bag if your pad in not insulated you will get cold at night. A sleeping bag does not insulate you from the ground no matter what it's rating is."

++1!

my last 3 trips have been mid to late September. Last year was from the 17th thru the 21st. It was chilly windy and rainy most of the week in the gunflint area but my 30 degree bag was very adequate. I did sleep in my long underwear a couple of nights. Never wished I would have brought my warmer bag. It may be more advisable though to prepare for the worst. I used the same bag in Colorado at 12,000 ft. in the snow including my long underwear and was fine. Temps around 30 degrees.

minnmike: " In the end if you are anything like me you probably already made up your mind. You just wanted people to reinforce your decision. The people that didn't have flawed thought processes. I say this with a smile on my face if you don't recognize the humor/truth."

+1 LOL you said what I was thinking..