The mercury could rise to 21C in parts of western Scotland this week - ten degrees above the October average.
But Met Office spokeswoman Nicola Maxey warned that the fine weather will be "short lived" as gales of up to 80mph are expected on Friday.
Heavy rain is currently sweeping across the west of the country and a yellow "be aware" warning has been issued until midnight tomorrow.
Ms Maxey said: "There is certainly going to be a lot of continuous rain."
The Met Office website warns there is a small chance that homes and businesses could be flooded, that communities could be cut off by flooded roads, and that trains and buses could be cancelled.
However, the east of Scotland is expected to stay mainly dry.
Once the rain clears, temperatures are expected to soar across the country with parts of the south and west likely to be the warmest.
Ms Maxey said that 19C-20C is likely in Glasgow on Wednesday and Thurday, with 21C possible in spots where the sun is out for longer.
She explained: "There is a cold front pushing slowly northwards, so as we go through today and tomorrow the heaviest rain will slowly start moving further north. Warm air is being pulled up behind that from the continent."
Residents of Edinburgh and Perth will likely see temperatures in the high teens on Wednesday and Thursday, while it is expected to be slightly milder in Dundee and Aberdeen.
The Met Office website predicts a high of 17C in Inverness on Wednesday.
Ms Maxey said the highest October temperature ever recorded in Scotland was 27.4C in Tillypronie in Aberdeenshire on October 3rd, 1908.
The average daytime temperature for October in Scotland is 11C.
But this week's Indian Summer will be cut short after the Met Office issued a yellow warning for wind, due to hit the west of Scotland on Friday.
Ms Maxey said: "There is another low pressure system crossing the Atlantic which is bringing blustery conditions. The exact timing of that system is still a bit uncertain so this will be refined as the week goes on.
"You are looking at 50-60mph gusts quite widely and up to 70-80mph in more exposed parts. So there will be blustery conditions with some more rain."
The wind warning, which covers all of the west of Scotland and Northern Ireland, is currently in place from between 5am and 9pm on Friday - but this is subject to change.
The Met Office website warns of a "small chance of injuries and danger to life" from flying debris, as well as possible disruption to rail, air and ferry services.
Power cuts are also a slight possibility and motorists on coastal routes are urged to be aware of large waves.