“TV and radio signals can be affected by atmospheric conditions, including high air pressure (which brings fine weather), heavy rain or snow.”
A spokesman for the service told the BBC that the situation was “uncommon but unpredictable”.
“It’s impossible for us to say [how many people have been affected] but it’s clear the disruption has been widespread across England and Wales,” he added.
“The good news is that during the course of the day the issue has lessened as the weather front moves through.”
Weather forecasts suggest the problem will continue for some into the evening, but a weak weather front is set to move in from the north on Thursday morning that should be more favourable for transmissions.