Unna

If you did most of your camping in the highlands, I could see someone buying a lightweight Hilleberg and using it year round. There's more than sufficient ventilation for the summer (not that it gets that hot there anyways), and the tent will stand up to the crazy wind they get there. An Unna weighs 2kg on the nose, they're not *that* heavy if you're not talking about an "expedition base camp" type tent

Pretty much all of the Hilleberg red and black label. Nallo and Soulo are classics. Nallo has more space for its weight and the GT has a wonderful vestibule. Soulo is the strongest 1 person and if you want to go overboard with the strength and camp in 70mph regularly then you can get black label version. Tarra if you want insane strength but will be heavy for one person. Unna is another good one, nice space, not as strong as a Nallo or Soulo but hardly weak, but it does like a vestibule (many unclip one corner). Terra Nova Quasar is another very strong tent, 7 crossing points in its geodesic shape so can cope with snow loading unbelievably well. But it is an inner pitch first which in rain isn't ideal. Slingfin make some good 4 season tents, the crossbow for example, contrary to common belief it isn't necessarily an inner pitch first but it is a bit of a hassle to set up the fly and then put the inner inside. But they use internal guylines as well so are stronger than the shape would suggest resulting in a spacious, relatively low weight tent. I personally have the Nordisk Seiland, more or less a Nallo GT. Slightly bigger and with better ventilation but slightly thinner fly fabric. I've had it in pretty high winds, but have seen a wind tunnel test up to 80mph with single poles. Have also used with friends a couple times and works well, lots of space in the vestibule. Tarptent Scarp is another UK classic, very strong for its weight, sorts out the space issues facing the Hilleberg Akto, just slightly bigger but makes a big difference in long nights, and the crossing poles allow it to cope with high snow loading. Also the Arcdome, very similar to the Unna, but has a vestibule, cheaper as well and comes with a 2p version. We'll see over the coming years, but looking at the design it might actually be slightly stronger than an Unna. Nortent does have strong tents, but they are a bit heavy on the marketing. The Vern is a bit well known for having some strength issues when it first came out, though looking at the Varde I can't see those in the same way (but the double door does mean that regardless of which way the wind is blowing one of the storm flaps will be in the wrong orientation). Almost anything by Samaya, but they make Hilleberg look cheap so there is that. They specialise in breathable single wall tents, and are the only manufacturer that is generally agreed to have manufacturing quality above Hilleberg. And lastly, possibly good fit, possibly not, the MLD Trailstar. When lots of people say four season here they just mean they want it strong for wind, in which case this is a large, very lightweight tent capable of performing in over 60mph. But it's design doesn't lend well to snow loading so if you will be doing lots of winter camps where it may snow heavily overnight it won't be a good option. But if all you care about is wind performance then you won't find anything as good for nearly the same weight. Tom Heaney on YouTube has some fantastic reviews of tents, buys all his tents or borrows from friends, no sponsorships. He's also the only YouTuber I have seen that holds the wind speed measure in the right place instead of walking off a few paces towards the ridge which results in higher wind speeds than what the tent faces. He has a wonderful video "the best two-person four season tent" comparing the Tarra, Quasar and Staika. And he personally loves Samaya. Really, there's lots of tents so I'd recommend choosing a type of tent, tunnel, geodesic, dome based on what you most value, be it strength, space, strength per weight. Then after choosing what type, choose the exact tent.

If you’ve got to carry it yourself, a Hilleberg Unna will take you and a dog comfortably. Failing that a Namatj 2 as suggested elsewhere (I swapped to the Unna for a weight saving). BUT when you say 4 season that recommendation is based on real 4 season, say Cairngorms or windy/wet peaks. If it’s just for cold weather, a Durston X-Dome or X-Mid solid would work - way cheaper and way lighter.

Same - I wanted to test the X-Mid’s limits. I now use it from March to September and never anywhere near real tops or in high wind. The Unna on the other hand is pretty bomb proof.

The two obv dome tent contenders (Arc and X) advertise solid inners, but the images show unsealable panels near the top for both. Most of the time this is okay, but when it's super gnarly fine snow dust could cover everything inside. There would be additional heat loss, too. Minimally but still. Actual full solid inners would add no weight to these otherwise fine offerings, but alas. This is an unfortunate design decision, because a true Scandinavian style dome with all the defenses done right is 600-900g more. Mids are good choices, but stake points needs to be extra solid, and overnight snow takes some user participation to not shrink the floorspace uncomfortably. I find UL mid inners to be mostly fiddly, saggy and confining - and sourcing a true solid is near impossible. So for mid use in real winter (year round actually) I skip inners. Then you can dig a footwell by the door and enjoy maximum space. And space is important with all that bulky winter gear and potential inside chores. My winter tents are a Silvertip mid, an Unna dome, and a Kaitum 2 tunnel

I would normally suggest the Hilleberg Soulo, but you are probably too tall for it. The Hilleberg Unna is another solid option, with much more space. It looks like it has no vestibule, but you can unclip the inner in one corner to create one. Sticking with Norwegian tents the Nortent Vern 1 is a good option, or Varde 1 though it is quite heavy. As a bit of a wild card look at the new TFS Saga tent. It hasn’t been released yet, but there are several teaser videos on the TFS YouTube channel. It is aimed at the UK/European market. Suitable for taller European users, high winds and damp conditions. I think it will be available at the end of the year. I’m not sure any of these tents are truly ultralight, but realistically a 4-season tent that can handle high winds is going to be 2kg+. Checkout novice wild camper on YouTube, he is 6’5”, and does a lot of 4 season tent reviews from a British perspective; high winds and wet conditions. https://youtube.com/@novicewildcamper

Hilleberg is solid but damn those prices hurt. If you're not doing serious mountaineering the MSR Hubba series is way more reasonable and still built like a tank

People shit on hilleberg prices till they use a hilleberg in less than ideal weather. I’ll tolerate the price for the long life and ability to handle some nasty weather. Most places in the states below tree line don’t need one though.