Good to see a post from you!
The Korean peninsula has very pronounced seasons. Summers there are very hot and humid while the winter season is cold and dry. This is because of the monsoon effect in the summer and the reverse monsoon effect in the winter.
The interior of the Eurasian continent becomes very hot during the summer, which creates a persistent thermal low pressure zone in it, which draws in warm and humid air from the Pacific. During the winter the reverse happens and the cold dry winds from the north prevail.
Interestingly, the average nightly minimum in Seoul in January is -6 C, which is almost as cold as in Helsinki. The daily maximum in January in Seoul is a +2 C while that of Helsinki is -1 C. Seoul is much warmer in the warmest month (August) with the average daily max/min being 30/22 C whereas in Helsinki they're are 22/15 C in July, the warmest month. Helsinki is MUCH drier in the summer: 65% in July. The interior of Southern Finland is somewhat drier than that.
I live in Lahti about 60 km to the north of the Gulf of Finland. The region that has the most similar climate of all on any continent outside Europe is north-central Alberta, Canada. Somewhere between Edmonton and For McMurray is the locality that matches the climate over here almost as perfectly as possible on Earth.
The Rockies convert the latent heat in the moist air from the ocean brought by the prevailing westerlies into higher temperature while reducing the moisture and thus taking the edge off from the frigid northerly winds that sweep the North American plains unimpeded in the winter. The Scandinavian mountains do the same to the moist air masses from the Atlantic. Finland is similarly exposed to southerly winds bringing in very warm air masses during the summer.
Eastern Canada has more pronounced seasons. Northern Ontario and Quebec have warmer summers and colder, snowier winters. Even Saskatchewan has colder winters than Alberta. I think Winnipeg in Manitoba had the coldest winters of all the large metropolises of Canada. It's right in the center and does not benefit from the warming effect of any large body of water thanks to the prevailing wind direction.
I've lived in both Seoul and Toronto long enough to get a feeling of the weather.
Seoul's winters are very dry and enough snowfall for any activity is rare. I miss Canadian winters sometimes. They are a lot more fun.
In Korea, most of the rain comes July and August. This year we had one 24 hour period of 150mm in July and another of 300mm in August (A 120 year record). The latter overwhelmed storm drainage and flooded low-lying parts of the city. I wasn't near any of the areas that got flooded, except the rivers and streams where that is normal.
Southern Ontario is interesting because of the lake effect. The great lakes have a unique impact on the weather.
I recall that there wasn't any natural snow anywhere at the Winter Olympics in South Korea in 2018.
300 mm of rain in 24 hours is a huge amount. Average annual precipitation where I live is 637.7 mm.
The lake effect not only moderates the temperature extremes but it can result in massive snow dumps when cold air freezes the water vapor emerging from the lakes. It's more likely to happen on the eastern shores of the large lakes but any locality near the shores is susceptible. Keweenaw Peninsula in Upper Michigan is the snowiest place in the Great Lakes region.
If it winds from the east-southeast, Helsinki may experience what is called the St. Petersburg snow machine early in the winter. After the Gulf of Finland freezes over that does not happen.
An acquaintance of mine lives in Missisauga. He wrote in his blog that he experienced +27 C and -10 C within a single week in one March about 20 years ago.
I definitely experienced some weird days when I lived in the Toronto area. I recall wearing t-shirts outside some days in February and like a week later it was -20C again. The western part of Canada gets something called the Chinook Wind which also creates a weird local weather effect.
I've never seen the frozen ocean before, other than maybe looking out an airplane window. Ontario does have a railroad going up to the ocean, ending at a small town called Moosonee, but I don't know anyone that's ever been up that far. I'm not even sure you can drive up there except during winter and running out of gas would be fatal.
The Chinook wind is called the Föhn effect in Europe. That's what makes Alberta warmer than the more easterly continental provinces.
Although the Föhn effect caused by the Scandinavian mountains is somewhat attenuated when it reaches Finland, it may still cause notable warm spells in the western and the northwestern parts of the country in particular.
Moosonee is at the southern tip of James Bay, which is a southern extension of Hudson Bay.
There could be a winter road to Moosonee from the south. Google Maps shows a road between Moosonee and some more northerly localities along the shore.
I've watched Ice Road Truckers. It's a fascinating show. Those people have to deal with some pretty extreme conditions.
Trying to drive up there would be ill-advised indeed. You could bring enough fuel with you but your car could break down or the road might be impassable or too dangerous to drive on.