The Mohe authority announced that temperatures fell to minus 41.1 degrees Celsius on Tuesday, minus 42.1 on Wednesday and minus 43.5 Thursday, the South China Morning Post reported.
A cold front approached the northern city on Monday, causing temperatures to drop by between 12 and 20 degrees Celsius.
Authorities were subsequently forced to issue the city's first-ever red warning for cold weather. The Heilongjiang Meteorological Bureau also issued an orange warning for cold weather for the whole state.
Visibility was reduced to less than 100 meters, but the hostile conditions did not dampen the spirits of some brave tourists, who ventured outside to witness the meteorological phenomenon.
Videos emerged on social media of people throwing water into the freezing air, causing it to turn to ice immediately.
Ice fog only occurs in the world's coldest regions, as water droplets suspended in air can remain in liquid form down to temperatures as low as minus 40 degrees Celsius.
It forms under specific conditions when high humidity is combined with temperatures no higher than minus 30 degrees Celsius, allowing for ice crystals to form in the air.
Mohe is the northernmost city in China and average temperatures remain below freezing for on average seven months of the year.
It is a phenomenon regularly witnessed in the Arctic and Antarctic, but can also form at extreme northerly and southerly latitudes, in regions including Alaska and northern Russia.
Mohe is located in the Heilongjiang Province bordering Russia, and is the northernmost city in the country.
The city is often referred to as "China's Arctic town," and is one of the few locations in China to have a subarctic climate.
Winter in the city beings in early to mid-October and lasts until late April, and average temperatures stay below freezing for roughly seven months of the year.