Raindrops hit a surface
Rain mixed with dust from the Sahara can give it a red, blood-like colour iStock

After Tuesday saw temperatures reach a scorching high of 33.5 degrees in certain parts of the UK, Wednesday is set to feature thunderstorms and the terrifyingly named, blood rain, according to the Met Office. Severe thunderstorms have already been seen breaking out in the north of the country while temperatures stay high in the south.

The blood rain weather phenomena is expected to hit the north, midlands and south west of England on Wednesday. But what is the ominous sounding 'blood rain'?

According to the Met Office, blood rain is rain that has such high concentrations of red dust mixed in the drops that it has a red appearance. Though, the weather service also note that blood rain is not a scientific term and as such there is not a set definition.

The red dust that causes blood rain in the UK usually comes from the Sahara, showing how vast the systems that affect our weather really are. The Met Office says that proper blood coloured rain is very rare in the UK and mostly dusty rain will look normal, simply leaving a dust film after it has fallen.

The Met Office said on Tuesday that the recent temperatures are part of a mixed weather pattern that will result in the "violent" thunderstorms that are hitting the UK: "The very high temperatures of the last couple of days are going to combine with Atlantic weather systems to set off some violent ‪#‎thunderstorms ‬across the north of the UK tonight and tomorrow. Watch out for some spectacular lightning and hail as well as heavy rain."