SUL in Cold vs. Warm Weather

John, I don’t have an answer, but a previous poster from staff suggested one extra layer per 20’F temperature change from your warm weather basis. So maybe predict +1 KG per 20’F of clothing ‘readiness’.

This brings up a bigger point, which is that Base Pack Weight BPW usually includes the pack, gear, and “three season” clothing carried (not worn). That last item can vary considerably based on location. I would like to ‘normalize’ these variations by defining ‘Core Pack Weight’ CPW; which would be the pack and gear with no clothing. Thus we could compare CPWs more objectively and without regard to individual metabolic rates.

CPW plus all clothing would still equal Total Base Weight; just as BPW plus clothing worn always equals TBW.
Comments? Core Pack Weights anyone?

>However, assuming cold weather range is 15 F to 45 F, snowy, rainy, dry…and warm weather range is 35 F to 70 F say rainy, dry etc.

Yep, that sounds like Wyoming summer. (“Any day of the year…”) Or as Mark Twain remarked, “The coldest winter I ever spent was a summer in Montana.” There’s a fair chance you’d see most of the above on a 2-week alpine trek. Thus, my trekking gear, even in mid-summer, is 3-season and therefore no change in Base Pack Weight.

> How much does your Base Pack Weight change and what would you add or subtract from your gear list.

To answer your hypothetical question, the only thing I would change is my sleeping gear: switch from my hammock with JacksRBetter Nest down quilt on top and Hennessy Hammock SuperShelter underpad/undercover beneath for your warm weather, to Ray-Way Deluxe 1-Person Quilt with Extra Layer PG3D as top quilt and use the JacksRBetter Nest as an under-quilt for your cold weather. The difference in weight is about one pound. I guess I’d also bring a heavier pair of mittens.

Brett, your CPW measurement sounds like an interesting idea. It would also help normalize the difference in base weights between bigger and smaller hikers. Coming from someone who is 6’3″, that extra fabric in clothing can add up. Now it won’t account for needing a size Long bag, but I guess you can’t account for everything…