Window frames filling with water

[ade11]

Last winter I had an incidence of water coming through a UPVC window frame by actually filling the frame then dripping onto the interior ledge. This window is on a gable end, upstairs, the house is stonebuilt, 1921, and there is a stone lintel above the window. Re-pointing the top of the lintel seemed to cure the problem, but now it has returned, although not as bad. Yesterday, after a night of heavy rain, I opened a different UPVC window, a hinge up type, and water started dripping out of its frame, continuing for some time. This window is also on a gable end, with a ston e lintel. This was inspected and the pointing is sound. There is a minimal cavity in the walls, about an inch, could rain find its way into this ? The gap where tiles meet roof is filled with concrete, which has never seemed very satisfactory, and has needed constant maintenance over the years.
The pictures are - first, the left side of window on the right ( they are windows for two rooms ). This was the initial leak. Second - window on right, water in the frame of the small central window.
Any help much appreciated.

 

[Ivor Windybottom]

It's probably condensation, from the air in the room.

Is there a drainage/ventilation gap at the bottom? There should be a gap between the frame and sill, there shouldn't be any sealant between them.

Alternatively the rain may be getting into the weep vents.

 

[ade11]

There was too much water for condensation, it only occurred during rain and ,so far only with these specific windows. Pointing the lintel the first time it happened seemed to stop the ingress, for a while at least. What and where are 'weep vents' ?

 

[ade11]

I may have answered this myself, having done some reading on UPVC windows. I did not realise the seals could fail long before anything else, looking at the small window I found one corner of the seal lifted by muck jammed under it, which would definitely let water into the frame.