Flooding could hit parts of Tayside, while other areas of the country will be bathed in sunshine and enjoying temperatures up to 17C.
The Met Office has issued an amber “be prepared” warning for the Highlands and Islands with persistent rain expected to last into Sunday afternoon.
It has led to flood warnings in the Tayside, Argyll and Bute, and the Highlands where rivers are expected to swell.
But while the rain falls, large parts of the north east will have clear skies and temperatures reaching 17C, warmer than Istanbul and Corfu this weekend.
The average temperature in Scotland last month was 2.9C and the expected increase today is due to a weather band crossing the Atlantic from the Caribbean, forecasters said.
The highest temperature recorded in the UK so far this year was 16.5C at Exeter Airport on January 9.
Met Office meteorologist Nicki Willis said: “There’s a mild airflow pushing over the UK bringing persistent rain to western high ground in Scotland but to the east of that we can expect a warm breeze leading to temperatures of 17C or so.
“With heavy rain expected in the western Highlands there is a warning in force right through to Sunday with a risk of some river flooding. Temperatures generally will be well above freezing overnight with some strong winds along the western coast keeping temperatures up as well.
“On Saturday, the best of the temperatures will be in central and eastern England and parts of Aberdeenshire where it will certainly reach the mid teens and possibly higher.”
Police in the Highlands have warned motorists to take care while travelling over the weekend and the Scottish Government will monitor the situation.
Environment Minister Aileen McLeod said: “The forecast is for heavy and prolonged rainfall across parts of the north and west. The wet weather, combined with snow melt caused by very warm temperatures, is expected to cause river levels to rise, particularly in Lochaber and around the Great Glen as well as the Beauly, Conon, Ness and Upper Spey.
“Members of the public should be alert to the risk of flooding in these areas and the potential for disruption.”
Transport Minister Derek Mackay warned about possible disruption, particularly between Fort William and Inverness.
He said: “Our operating companies will be doing all they can to mitigate the effects of the storms by clearing drains and gullies but the extreme conditions mean that there is a chance of flooding on some routes.
“Drivers should check conditions before they travel and leave some extra time for their journeys. Live information on conditions is available on the Traffic Scotland Twitter feed, smartphone App, internet radio and website.”