Yesterday afternoon the Bakerloo Line had 'minor' delays due to signalling problems at Queens Park. This morning (as at 06:30) the problems have moved down the line a bit to Baker Street.
You can check the departure boards for Baker Street here, to gauge whether things have got any better by the time you read this.
What I can say is that it is going to be jolly uncomfortable down there today. Today's weather is forecast to be hot and sunny, a little warmer than yesterday. I know that the British definition of hot is not the same as in some other parts of the world, but nevertheless I can vouch for the fact that the Bakerloo Line was sweltering yesterday. It is likely to be just as bad today.
It is probably a good idea to heed the official advice - carry a bottle of water with you. I'm still tending towards tube avoidance, so walking today will probably raise my temperature just as much as entering the underground furnace.
Be careful out there.