That low in Perth was accompanied by -8C in Braemar, -7C in Glasgow and -5C in Edinburgh.
Further sub-zero conditions are forecast for tonight, including -6C in Aberdeenshire and -1C in Edinburgh, before the weather turns milder tomorrow and on Friday.
The latest Met Office yellow “be aware” ice warning, which also covers much of England, will be in force from 6pm to 11am tomorrow.
It covers the whole of Scotland apart from eastern Fife, Tayside and Aberdeenshire, and the western edges of the Hebrides.
The agency said: “Another cold night with a risk of ice, either where surfaces remain wet from daytime showers, or where further wintry showers fall onto frozen surfaces during the night and on Thursday morning.
“Showers will be a mix of rain, sleet and snow, with some slight accumulations possible, mainly above 200 metres.”
Yesterday, heavy snow forcing the suspension of runway operations at Glasgow Airport for an hour, with seven flights diverted to Edinburgh, Prestwick and Aberdeen.
The snow also caused significant disruption on the roads, with police receiving reports of more than 125 crashes, many due to the weather.
Both main roads into Oban were impassable for a time, while other blockages included on the A83 at Minard south of Inveraray.
Crashes linked to the weather included on the A82 in Glencoe, while the M74 was among other roads affected.
Eight schools were closed in Argyll and three in the Highlands.
Diverted flights at Glasgow included services from Reykjavik and Amsterdam.
In Oban, a five-mile queue on the A85 tailed back to the Connel bridge.
Volunteers with snow shovels joined police to spread sand on the steep Bealach-an-Righ on the road into the town.
One driver said: “Glencoe was snowy, there was lots of snow there and the glen was shut due to snow and black ice.
“When I got to Appin, the road was quite dodgy and when you came to the Oban road off the Connel bridge, with everyone coming in to work, the road was gridlocked. There was a lorry stuck on the hill coming into Oban and a car was off the road.”
Last night, trunk road maintenance firm BEAR Scotland deployed 35 gritters across the north west, while Scotland TranServ had 32 operating in the south west.
ScotRail passengers were disrupted by a train breaking down at Haymarket in Edinburgh and a points problem at Exhibition Centre in Glasgow.