In the capital Riyadh, the temperature dipped close to zero and the streets were deserted Tuesday and Wednesday nights.
In Tarif, on the border with Jordan, the temperature hit minus 5 degrees Celsius, according to the weather services.
It dropped to minus three in Hail further southeast, and minus 2 in Arar on the border with Iraq.
The kingdom is known for its extreme heat, particularly during summer.
“The country is experiencing its most intense cold snap since 2016,” stated Hassan Abdallah, from the Wasm meteorological centre, on Thursday.
In neighboring Iraq, where summers are also scorching, Baghdad residents woke up Tuesday to find the city carpeted in white from only its second snowfall in a century.
The last recorded snowfall in the city was in 2008.