UKH

Going to be hut-tripping in the Alps and just going to use my phone for the camera (and making calls). 

Any reccomendations for a waterproof case that can be used with gloves/cold fingers, and/or one that has a battery pack attached, or is it worth looking at getting something like a solar Power Monkey?

I've never had much good experience with solar chargers, i'd sugest a separate battery pack and they come in anything from about half a charge to 10 full charges so you can select the ideal for your trip.

I've used diving phone pouches like this (https://www.decathlon.co.uk/watertight-phone-pouch-l-id_8362014.html?iv_=__...) and they are great at waterproofness but they are slow to react to finger touches and the camera loses clarity too.

I just sent an expensive solar charger back as it simply didn't work as advertised.  Yes in bright sunshine it charged the phone very slowly but if there was any cloud it did't even help my phone hold the charge it already had, it continued to discharge.

Al

I don't have much experience with solar chargers.

If you want just a power pack anker gets my vote. Like others I've tried the solar panels and never found them any good 

Cheap solar power banks are usually just a power bank with a fancy cover.

If it's for one short trip, I'd just get a large enough power bank.

For longer trips a separate solar panel and bank is good.

I borrowed a 9W Goal Zero from my brother for a a couple of months living on the beach in Mallorca and that was fine for keeping the phone and a cheap single charge bank topped up on sunny days, but the problem is that when the panel voltage drops the phone or power bank will stop accepting charge.

I believe Goal Zero's own power banks are designed to allow trickle charge at low voltage, so as long as you charge the phone off thetbank instead of direct you get a lot more out of cloudy days/partial shade.

I noticed they have a cracking offer on the goal zero on go outdoors, but I have no idea if they have sorted their shit out yet so I'd be wary of online payment...

Powertraveller Sport 25 will give you nearly 3 full iPhone charges and no need to take a solar panel, though they have one to match it. Its a light and rugged battery pack that I use on day walks and wold camps.  If you are not using the phone for Nav, then just turn off the GPS the wifi, the bluetooth and data connections and you will be good to go for days.  You can even turn the phone off and just turn it on once or twice a day. 

I found these review about solar charges: https://www.bestadvisers.co.uk/solar-chargers

And as I understood it can't be a case

It's just a device which not always waterproof

I know that in Apple shops you can find waterproof cases for Iphone. Haven't any ideas about other models.

Forget about solar chargers. The only ones that work are those 21+ Watts big folding ones, and even these need to be used stationary, without intermittent clouds or shading. The small "solar" panels you get on some battery packs like the monkey are a joke, these would not charge even a calculator (all the charge comes from the battery pack). Just a get a decent 10-20Ah power bank for topping up the phone in the hut and leave your phone in flight mode.