The weird occurrence was in the remote Eveno-Bytantaisky and Zhigansky districts of Russia’s coldest region – Yakutia.
The two districts are larger than England and Wales combined.
The region is so far north that at this time of year it expects virtually 24-hour light – but as one local said: “Day suddenly turned into a dark night”.
Officials have not explained why “the sun was switched off” – and some locals believe it was due to “devilry”.
Others blamed a massive cloud of choking pollution from ranging wildfires in eastern Russia.
“The sun went out around 11am, and didn’t come back until about 2pm,” a resident told The Siberian Times.
“I couldn’t see a thing without switching lights on.
“We took torches to walk outside, but actually no-one wanted to be on the street because the feeling was as if something heavy in the air was pressing on your chest.”
After the sun returned, locals found a thick layer of dust outside.
“Water in lakes went black because of dust,” reported an eye-witness.
The sun was not visible in the two neighbouring districts but no other area of the Yakutia republic reported the cataclysm.
“We wondered if this was an eclipse, but it can’t be something witnessed only by two districts.
“Normally before any eclipse the air temperature drops by 3 or 4 degrees centigrade, and true, that morning was cooler than usual.
“But our area is always quite cold, so we didn’t pay special attention,” said Maria from a village in Zhigansky district.
Neither district has been hit by the wild fires which have destroyed swathes of remote Russian territory this summer.
It is believed the cloud of thick pollution spread from the fires.