I have been inside a sauna and I believe the health benefits are dubious at best. Snowfall, the latest expansion for Cities: Skylines [official site], disagrees with me. It reckons that saunas are both recreational and restorative, a mix of a clinic and a park. Build one and your citizens will send a flood of smiles bursting out of your city like souls ascending to heaven. I don’t understand why this is. When I sat in a sauna EVERYTHING WAS HOT and the AIR ITSELF WAS HOT and don’t even get me started on the door or the floor or what it was like to even move an inch.

However, this concludes the design disagreements that I have with Snowfall, which I think is a rather lovely and charming addition to Skylines. Let me explain why.

First of all, winter has been turned up to eleven. It’s not so much that winter is coming, more that winter is here right now and it’s left the freezer wide open, made itself a dry martini and is sitting in your favourite armchair, ready to party, shedding snowflakes like dandruff. Snowfall comes with three permanently frozen new maps to play, places where the temperature happily hangs around -20 celsius even during the day. It took me a few minutes before I noticed the subtle new temperature gauge, slipped into the bottom of the UI, quietly hinting that my city needed more electricity and heating.

Heating? Ah yes, it turns out that keeping warm while the flurries fall requires a lot of energy and is a serious drain on your resources, at least until you find a way to pump heat directly into people’s homes. “You can do that?” I hear you ask, incredulous. Why yes indeed, with the new patented HeatPipes, to which your normal underground piping can be upgraded, exactly the way you’d upgrade your roads. Heat requires its own particular flavour of infrastructure and throbs out of the new Boiler Station and Geothermal Plant, with dense downtown areas naturally ending up warmer than rural homesteads where, no kidding, old people can slip on the ice and hurt themselves.

Of course, as mayor, burgomeister, prefect or equivalent, it’s your job to keep your citizens as safe as possible, which includes clearing your streets. These can clog fast when the snow falls and, while ardent motorists can still use all their Baltic brute to push their way through, a depot deploying plows is a good idea. Combine these with a snow dump, which is essentially a gigantic landfill for snowman biomass, and traffic can continue moving at appreciable speeds. If you want to be really helpful about it, you could even lend a hand with city ordinances that promote studded tyres, much as you’ve already made it law for buildings to be thoroughly insulated. Wait, you have done that, haven’t you?

Naturally, all of these things are more fixed considerations in chilly climates than they are in those with variable weather, something that makes Scandinavian settlements a little more challenging to run. Either way, they’re relatively subtle additions that certainly have an impact, but won’t ruin your cities or drastically affect your other priorities. In my complete cluelessness, I was able to fairly effectively run a city on a winter map without proper heating or road clearance for many hours before I realised how unhappy the inhabitants were. How unhappy and cold.

If you’re not quite so interested in legislating your polar people, you can still bring all the fun of Finland to them via a host of new, winter-themed entertainments that suit their tundra. For citizens who just can’t get enough of the cold, there are ice parks, ski slopes, alpine lodges and so much more for them to visit, enjoy and take bescarfed, hot-chocolate-sipping selfies in. There are ski slopes to be raised, Father Christmas waiting to be unlocked and curling rinks to be vigorously, vigorously, *vigorously* rubbed. To balance out the existential horror of the frigid blackness, Snowfall brings Skylines its biggest dosing of fun yet, to the point that I think this might be a little unbalanced. There’s maybe a bit too much fun in here and I would’ve liked more substance and variation. As I said before, winter has come. In a very unsubtle fashion.

And then there’s the trams. If you know Colossal Order, you know they probably did these with one collective hand tied behind their collective back. If you don’t mind squeezing out some of your traffic (and who but the craziest mayor doesn’t?), then you can rake tramlines down one lane of most of your roads, dropping stops like they were yesterday’s fashion and giving your commuters merry, chiming chariots.

Like buses, tram routes can be precisely defined, dragged and dropped, even micromanaged, though they still do a perfectly good job if you prefer a broad and hands-off approach. Just remember to connect the tram lines to a depot somewhere, so the serpentine things can ooze out like a snake from a pipe, before sliding off to swallow some willing passengers.

I’m not yet sure how effective they are versus the other and more established modes of transport, which I’ll need more time to tell, but I already feel like they’re better than buses. Naturally, they’re costlier as they require you to modify roads, but I think the tradeoff is worth it.

If I seem glib and gleeful here, that’s the mood that Snowfall has put me in. It’s appropriately light, pretty and fluffy. It doesn’t represent any sort of dramatic paradigm shift for Skylines, but it adds a light dusting of additional considerations, should you want to handle a winter wonderland. Of course, not every mod piece of custom content that you’ve meticulously selected is necessarily going to function with this new expansion and I should add that I switched them all off before I started on this new, dry run. The biggest drawback to Snowfall, much like After Dark, is that it will probably find a way to clash with one or two of your favourite custom additions. But if you’re a modder, I guess you already live life on the edge.

Otherwise, it’s a charming and worthwhile expansion for what is already an excellent city-builder. I have nothing but warmth for it in my heart.

Oh, and there’s also a curious new theme creator, free to everyone, which allows you to tinker with the world themes, environmental effects and so forth. If you really want, you can make a world where the moon is really big. Hashtag bigmoon. Do it.

Cities Skylines Snowfall is out today for Windows, Mac and Linux. Skylines was one of our favourite games last year, even though our succession diary ended horribly.