At this time of year, in early March, there is a lot of dead grass and heather left over from last year which can dry very quickly.
People who live, work or visit rural areas are being urged to exercise caution over the next few days.
The extreme warning – released in conjunction with the Scottish Wildfire Forum (SWF) – remains in place until Wednesday, 9 March. This covers West, North and North-East Scotland.
Deputy Assistant Chief Officer Bruce Farquharson, the SFRS Wildfire Lead, said: "Wildfires have the potential to burn for days and damage vast areas of land, wildlife and nearby communities.
"They can also impact negatively on the environment with the release of greenhouse gas emissions into the atmosphere.
"It is crucial that people act responsibly and always follow the Scottish Outdoor Access Code. Please think twice before using anything involving a naked flame."