Most of the country has been enjoying sunshine and warmth recently, with temperatures reaching a balmy 26C.
But conditions are set to change on Wednesday as a front of low pressure comes in, bringing increasing cloud, widespread showers and a risk of thunder and lightning in some places.
Forecasters say clouds will start gathering across the east from the early hours, but the worst of the rain will hit western and southern parts.
Thunder and lightning storms could also break out along with the heaviest rain.
Only the north of Scotland looks likely to escape the wet.
“Many parts of Scotland have been enjoying warm conditions over the past few days,” said Met Office spokesman Grahame Madge.
“That’s likely to change. We’ll see temperatures coming down.
“What we have is a shift in the weather pattern.
“At the moment high pressure is dominating but that is pulling away and will allow a low-pressure system that’s sitting out to the west of Scotland to take over.
“So from Wednesday into Thursday we’ll have a much fresher feel.”
The dreich conditions look set to continue throughout the week and into Saturday and Sunday.
Mr Madge said downpours will never be too far away, but there could be sunny spells too.
He added: “That low pressure will bring in weather fronts this weekend. Some of those will contain rain, heavy at times, but it’s not a complete washout.
“Although it will remain quite breezy throughout, there will be clearer periods and gaps in between those showers and we may get prolonged periods of brightness.
High temperatures affecting rails forced emergency speed restrictions to be put in place between Stirling and Dunblane, delaying or cancelling at least 15 ScotRail trains.