coldest month of the year averages -75C in some inhabited areas
The sublimation point of CO2 ice is -78°C. This implies that some of your settlements get dry ice snow, which will have interesting effects on your atmosphere. Assuming your settlements aren't in the coldest bits of your world (polar or mountainous ice caps) you're going to have some odd atmospheric effects, and probably layers of buried dry ice in ice caps. Melting of ice caps might trigger really exciting rapid global warming effects.
edit it also occurs to be that if enough CO2 precipitates out in the winter, then the later winter/early spring thaw might result in pools of deadly gas forming. CO2 is heavier than air after all, and on a calm day it may not mix quickly enough with the rest of the atmosphere. Living in a basement in such circumstances is probably hazardous. See also: Lake Nyos disaster.
That aside, you have to worry about ice formation on the roofs and sides of your buildings, and issues with cold embrittlement of tools and structural metals (note that steel becomes brittle at -73).
Some of these cities are built in hilly/mountainous regions so if expansion did occur it would have to be along the relatively narrow valleys
Be careful about construction in mountainous regions with big temperature swings. Lots of fun rockfalls and ice falls and avalanches to look forward to.
According to the wikipedia article on permafrost,
Permafrost is soil, rock or sediment that is frozen for more than two consecutive years. In areas not covered by ice, it exists beneath a layer of soil, rock or sediment, which freezes and thaws annually and is called the "active layer". In practice, this means that permafrost occurs at an mean annual temperature of −2 °C (28.4 °F) or below. Active layer thickness varies with the season, but is 0.3 to 4 meters thick
Your hilly areas, and valleys, are very likely to have a permafrost layer unless the winters are very short or the summers are lethally hot. Permafrost has a major impact on construction, because temperature fluctations in the upper layer cause ground to significantly soften in summer and then refreeze in winter with ice expansion capable of damaging foundations. Here's a building in Longyearben on Svalbard up above the arctic circle:
Note that it is built on legs. Amongst other things, this helps prevent the heat of the building contributing to melt underneath it which could destabilize the foundations. In such conditions, no-one will be building sky scrapers!
(the linked settlements from the wikipedia article such as Yakutsk are probably relevant to your interests, as they are permafrost towns with record low temperatures approaching your average low temperatures)
That limits tall building construction to places where massive stable bedrock is accessible from the surface, avoiding the instability of the regular ground. Such construction is likely to be very expensive and require hefty bits of machinery to accomplish. This might well mean that the places where you could most commonly (and cheaply) build large settlements, nice wide open plains, are the places where you're least likely to find very tall buildings!
Assuming you still want your expensive cities on rock, "sky scrapers" seem likely to be much lower and broader and maybe even have sloping sides to mitigate excessive structural loading by ice and snow and to reduce the problem of ice breaking off the upper levels and falling onto things below around the building. Construction of tall buildings in hostile environments is challenging at the best of times, but maintenance of them is going to be worse... dealing with exterior damage on a very tall building in the winter is likely to be impossible!
Remember also that modern day super-tall sky scrapers are largely commercial buildings, with residential tower blocks being rather shorter, and both only really exist where land prices are high and minimizing the footprint of your building makes sound financial sense. Given how challenging the construction and maintenance is likely to be, and how unpleasant the winters will be, I can't help thinking that the skyscrapers will be further south in places where there isn't permafrost to deal with and the winters are less severe.
Additionally, you might consider that digging down below the permafrost level (where possible) might be a more sensible place to build. Ground temperatures are likely to be much warmer than surface temperatures, and there's substantially less risk from the weather. Underground cities might make a lot more sense than super-tall above ground ones, under the circumstances. (edit: at least in places where you don't get significant CO2 snow, at leas.t)