Bag Temp Question

[upandover]

I'm planning on starting a thru hike starting May 15 (northbound). I currently have a 40 degree EE quilt. Is that good? I assumed it would be but just came across some info that suggested its not warm enough?

If not warm enough what should I do to remedy situation. I'm thinking either get a liner or bring a puffy jacket I could wear while sleeping. But a puffy jacket seems like overkill for that time of year.

Thanks.

[Mockernut]

A puffy is never overkill, I would say it's mandatory. You'll be OK, maybe, if you sleep warm but the Smokies and high elevations will still have cold nights. I have a pile of sleeping bags but none rated over 25 degrees. I would rather sleep with the bag zipped open than ever be cold. I took a guy into the Slickrock wilderness in the fall last year, night temps in the 40s. He took a 40 degree bag and froze. We had to quit a day early. Test it now if you're not sure.

[upandover]

I did use the bag for a month last year from mid PA to Benington, VA. Started May 15 and ended June 15. If the quilt worked for that time and place will it work for what I have planned for coming May? I mean, I'm sort of assuming its going to be hot as hell.

[upandover]

* Benington, VT

[jeffmeh]

I don't think a 40F rating will be adequate when you get up into NH and ME. There are plenty of nights in the Whites in the summer where it wouldn't be adequate. Of course you might be able to make it work with layers, but I would go with a warmer solution.

[Mockernut]

I've had nights in the 30s and 40s in June in the Smokies...one time in July.

[HankIV]

It’s pretty subjective. Best bet would be to try out now in your back yard at temps you might experience. Use the sleep system (quilt, pad, clothes) you would use, and shelter.

[Daybreak]

The issue for the southern AT is elevation. Temperatures drop about 5.4 degrees F per 1000 ft. The trail elevation in the north half of PA never exceeds 1600'. The first shelter above 1600' is Riga Shelter (mile 1510) and above 2000' is at Mt Wilcox (mile 1541) just before Upper Upper Goose Pond Cabin in northern MA. These elevations are from the WhiteBlaze Shelter list. Springer Mountain Shelter sits at 3730' while the rest vary between 3000' and 4900' until you get to the Smokies (except two). The shelters in the Smokies range from 1175' (Fontana Hilton) to 5900'. Clingman's Dome (mile 201) is the highest point on the trail at 6643'. Roan High Knob shelter (mile 379), north of the Smokies is the highest shelter on the trail at 6285'.

Listed below are the mean low, 25 percentile, and 10 percentile temps (F) in Gatlinburg (1039') for May 1, June 1, and July 1 and estimated temps adjusted for altitude. Some seem on the low but its give general picture.

Mean Low temp by elevation based on Gatlinburg
	temp (F)
elev ft	1-May	1-Jun	1-Jul
1039	49	58	64
2000	43.8	52.8	58.8
3000	38.4	47.4	53.4
4000	33.0	42.0	48.0
5000	27.6	36.6	42.6
6000	22.2	31.2	37.2
25% of day temps will be at or below this temp.
	temp (F)
elev ft	1-May	1-Jun	1-Jul
1039	44.0	54.0	62.0
2000	38.8	48.8	56.8
3000	33.4	43.4	51.4
4000	28.0	38.0	46.0
5000	22.6	32.6	40.6
6000	17.2	27.2	35.2
10% of days temp will be at or below these values
	temp (F)
elev ft	1-May	1-Jun	1-Jul
1039	38.0	49.0	57.0
2000	32.8	43.8	51.8
3000	27.4	38.4	46.4
4000	22.0	33.0	41.0
5000	16.6	27.6	35.6
6000	11.2	22.2	30.2

Gatlinburg temp map. Note that the variation in temperature narrows as you head toward summer and from another graph

https://weatherspark.com/s/16309/1/A...es-Temperature

Elevation profile (Postholer.com) from about MD/PA line (mile 1070) to Hwy 9 (Bennington mile 1612) and for the trail
Attachment 50251
Attachment 50252

Finally be aware that it is 1.2 to 1.4 times more likely to rain in Gatlinburg than Allentown. Think cold rain. Damp bag.

[Daybreak]

Beware the two postholer attachments have different scales. I didn't catch the scale change. Basically the OP hike started the low area of the trail.

[gpburdelljr]

The issue for the southern AT is elevation. Temperatures drop about 5.4 degrees F per 1000 ft. The trail elevation in the north half of PA never exceeds 1600'. The first shelter above 1600' is Riga Shelter (mile 1510) and above 2000' is at Mt Wilcox (mile 1541) just before Upper Upper Goose Pond Cabin in northern MA. These elevations are from the WhiteBlaze Shelter list. Springer Mountain Shelter sits at 3730' while the rest vary between 3000' and 4900' until you get to the Smokies (except two). The shelters in the Smokies range from 1175' (Fontana Hilton) to 5900'. Clingman's Dome (mile 201) is the highest point on the trail at 6643'. Roan High Knob shelter (mile 379), north of the Smokies is the highest shelter on the trail at 6285'.

Listed below are the mean low, 25 percentile, and 10 percentile temps (F) in Gatlinburg (1039') for May 1, June 1, and July 1 and estimated temps adjusted for altitude. Some seem on the low but its give general picture.

Mean Low temp by elevation based on Gatlinburg
	temp (F)
elev ft	1-May	1-Jun	1-Jul
1039	49	58	64
2000	43.8	52.8	58.8
3000	38.4	47.4	53.4
4000	33.0	42.0	48.0
5000	27.6	36.6	42.6
6000	22.2	31.2	37.2
25% of day temps will be at or below this temp.
	temp (F)
elev ft	1-May	1-Jun	1-Jul
1039	44.0	54.0	62.0
2000	38.8	48.8	56.8
3000	33.4	43.4	51.4
4000	28.0	38.0	46.0
5000	22.6	32.6	40.6
6000	17.2	27.2	35.2
10% of days temp will be at or below these values
	temp (F)
elev ft	1-May	1-Jun	1-Jul
1039	38.0	49.0	57.0
2000	32.8	43.8	51.8
3000	27.4	38.4	46.4
4000	22.0	33.0	41.0
5000	16.6	27.6	35.6
6000	11.2	22.2	30.2

Gatlinburg temp map. Note that the variation in temperature narrows as you head toward summer and from another graph

https://weatherspark.com/s/16309/1/A...es-Temperature

Elevation profile (Postholer.com) from about MD/PA line (mile 1070) to Hwy 9 (Bennington mile 1612) and for the trail
Attachment 50251
Attachment 50252

Finally be aware that it is 1.2 to 1.4 times more likely to rain in Gatlinburg than Allentown. Think cold rain. Damp bag.

in aviation the rule of thumb for a standard lapse rate is 3.5° F drop for every 1000 foot gain in altitude, up to 36,000 feet.

https://www.ctsys.com/standard-lapse...355%20%C2%B0C.

[Daybreak]

Google bit me again. The quick answer was 5.4. I think the 3.5 is better and appropriate. Also changed elevation to the airport.

Mean Low temp by elevation based on Gatlinburg (3.5 F drop/1000') temp (F) elev ft 1-May 1-Jun 1-Jul 1014 49 58 64 2000 45.5 54.5 60.5 3000 42.0 51.0 57.0 4000 38.5 47.5 53.5 5000 35.0 44.0 50.0 6000 31.5 40.5 46.5 25% of day temps will be at or below this temp. temp (F) elev ft 1-May 1-Jun 1-Jul 1014 44.0 54.0 62.0 2000 40.5 50.5 58.5 3000 37.0 47.0 55.0 4000 33.5 43.5 51.5 5000 30.0 40.0 48.0 6000 26.5 36.5 44.5 10% of days temp will be at or below these values temp (F) elev ft 1-May 1-Jun 1-Jul 1014 38.0 49.0 57.0 2000 34.5 45.5 53.5 3000 31.0 42.0 50.0 4000 27.5 38.5 46.5 5000 24.0 35.0 43.0 6000 20.5 31.5 39.5

I did a deeper dive. That site implied that 5.4 F/1000' works for clear days and 3.3 F/1000' for cloudy/raining days but I could not confirm this. I now discount them since their conversion to metric were wrong.

Clingman's data is not in the database. However, Asheville is and there is data comparing Asheville with Mount Mitchell showing the mean average difference by month. In any case it is all averaged data so there are large variations day to day particularly at ground level.

One can also use postholer.com, zoom in on SMNP, click the appropriate box to get mean low temperatures shown as a colored overlay.

[Daybreak]

Two articles on Mid-May starts. One froze in the south, the other in the north.

https://thetrek.co/appalachian-trail...bo-in-mid-may/
https://thetrek.co/appalachian-trail...thru-hike-may/

[HankIV]

I beefed up my 30F quilt for the Damascus to Springer chunk of my SOBO in Oct. by adding a second set of base layers and thicker sleep socks. Figured that gave me more flexibility than swapping for a heavier quilt or bag. Worked well for adapting to both warmer and colder nights.

[upandover]

The issue for the southern AT is elevation. Temperatures drop about 5.4 degrees F per 1000 ft. The trail elevation in the north half of PA never exceeds 1600'. The first shelter above 1600' is Riga Shelter (mile 1510) and above 2000' is at Mt Wilcox (mile 1541) just before Upper Upper Goose Pond Cabin in northern MA. These elevations are from the WhiteBlaze Shelter list. Springer Mountain Shelter sits at 3730' while the rest vary between 3000' and 4900' until you get to the Smokies (except two). The shelters in the Smokies range from 1175' (Fontana Hilton) to 5900'. Clingman's Dome (mile 201) is the highest point on the trail at 6643'. Roan High Knob shelter (mile 379), north of the Smokies is the highest shelter on the trail at 6285'.

Thanks Daybreak. This is the explanation I needed.

[Daybreak]

Those cold rainy days are the worst. I like having a synthetic hoody. May not be as warm as tight 2nd thermal layer but its easy and quick to get on and off. I like a puffy but always have a hoody. I don't worry so much about it getting damp. In wet conditions it's great for staying warm in an emergency, and in camp. If needed, it can dry in the sun or in the sleeping bag. Independent of the bag I carry, always wear some type of layer next to my body.

Beware it can be cool in VT and cold from the Whites on. Most earlier thrus use the 20F they started with. Even in summer months, you can get freezing nights and cold windy 30's rain.

Another way of estimating temps and weather is by monitoring the weather forecasts at various shelters and comparing temps at various altitudes and latitudes.

https://www.atweather.org/
https://www.atforecast.app/

[upandover]

Thanks for advice Daybreak. Do you (or anyone else) have an opinion on liner + sleeping bag?

I'm thinking this liner:
https://www.amazon.com/dp/B003BIT004...hruhiker.co-20

They claim it can add 25f of warmth. So I'm thinking that plus my 40f quilt should be good right?

[Time Zone]

Thanks for advice Daybreak. Do you (or anyone else) have an opinion on liner + sleeping bag?

I'm thinking this liner:
https://www.amazon.com/dp/B003BIT004...hruhiker.co-20

They claim it can add 25f of warmth. So I'm thinking that plus my 40f quilt should be good right?

IIRC, someone over at backpackinglight.com forums did some testing that indicated the additional warmth wasn't even half that much. I think the conventional wisdom is that the weight of the liner is better spent on additional insulation in the main bag. You can always vent it, if it gets too warm. Similar argument for nesting quilts ... you're carrying shell weight twice over, that's better allocated to more fill in one quilt, perhaps total weight would actually be less. But IDK ... YMMV ... perhaps double shells block more wind than a single shell with more insulation. Anyway, you should look around various forums ... this is just my impression, that most commenters on it that I've read seem to feel it's not nearly as effective as marketed, and the weight and bulk is better allocated another way.

A different case could be made for thin liners - keeping your bag cleaner, for instance.

[Kittyslayer]

Thanks for advice Daybreak. Do you (or anyone else) have an opinion on liner + sleeping bag?

I'm thinking this liner:
https://www.amazon.com/dp/B003BIT004...hruhiker.co-20

They claim it can add 25f of warmth. So I'm thinking that plus my 40f quilt should be good right?

You better do some back yard testing this winter. I doubt you will see an extra 25 degree from a liner.

Don’t forget the R value of your pad(s).

[HankIV]

I got fixated on the beginning of your trip too, like the rest. I think even beefing up layers, you’ll want something warmer north of Hanover. I would guess with other good sleep system elements you’d be okay with your quilt from Damascus to Hanover. Liners are okay, but add back in some of the confinement you are trying to get away from by having a quilt in the first place. An extra base layer will weigh about the same, can be used elsewhere and IMHO will be warmer.

And as Kittyslayer says, get a good pad.

[upandover]

this is just my impression, that most commenters on it that I've read seem to feel it's not nearly as effective as marketed, and the weight and bulk is better allocated another way.

This is what my gut tells me as well.