How cold does it have to be to snow?

Snow in Windsor. (PA)
The early morning snow on the Long Walk at Windsor Castle, Berkshire, as parts of the UK wake up to snow. (PA)

The UK experienced its coldest night of the year so far on Tuesday night, with snow falling in the south and more on the way for much of the UK through the rest of the week.

Temperatures at Kinbrace in the Highlands dropped to this year’s record low of minus 15.2C overnight – while many Britons woke up to a sea of white.

The Met Office have said in most places the snowfall will continue until Friday, with a yellow warning for snow covering all of the UK north of Birmingham spanning from 3am on Thursday until 6pm on Friday.

A yellow warning for snow and ice also covers London and the south from midnight on Wednesday until 9am on Thursday.

With more snow predicted, what causes it and what is the ideal temperature for it to settle?

The ideal range for snow in the UK is between 0-2C. (PA)
The ideal range for snow in the UK is between 0-2C. (PA)

How does snow form?

Snow forms in clouds that are around freezing temperature.

Tiny ice crystals in the air stick together to become snowflakes, and if they become heavy enough they fall to the ground.

The iconic hexagonal shapes of snowflakes reflect the shape of the H2O molecules arranged themselves into while in the freezing cloud. They keep this shape when they freeze.

How cold does it have to be to snow?

For the snow to fall from the cloud to the ground it needs to be above 0C, with almost snow occurring in the UK between 0-2C.

If snow settles or not depends on the ground it settles on. (PA)
If snow settles or not depends on the ground it lands on. (PA)

If it is above 2C then the snowflakes will melt and turn into sleet.

For snow to settle it needs the ground to be within the 0-2C range, otherwise it will melt.

Are there different types of snow?

Yes, primarily there are two types 'wet' and 'dry'.

If you've ever tried to squish a snowball together but the snow remained dust in your hand, that was because you were handling dry snow.

Snowflakes change in nature depending on the air they fall through as they leave the cloud.

If the snow fell through dry cool air then it will be more powdery and will not stick together, this usually happens when the temperature is very close to freezing.

If it fell through wet air slightly above freezing then the snowflake will begin to melt around the edges and become sticky, ideal for making snowballs,