Hill and Mountain Weather Advice

Some basics to understanding our mountain weather

Have you ever wondered why America and Russia (on the same lines of latitude as us here in the UK) seem to have massively colder winters and massively hotter summers than us? Here’s why …

Consider placing 1Kg of soil and the same mass of water into an oven. You turn the heat right up. Which of these will reach boiling point first and which will cool fastest?

The answer is that the soil will heat up fastest and then will cool quickest. Knowing this helps us to understand some basics around the UK weather. America and Russia are big land masses which quickly gain heat in the summer and lose it fast in the winter.

The UK on the other hand is a small island (of soil) surrounded by a whole load of water. We have the Atlantic Ocean on our western shore and then not so far away, Europe to the east. The Atlantic takes all summer to heat up and then takes all winter to cool down again.

This in turn means that during the summer months the sea around us is slowly warming up. Then by around autumn, it will be at its peak temperature before it slowly loses heat through the winter months. Most of our weather comes from the south-west and also from the warm water called the Gulf Stream (which originates in the Gulf of Mexico). Similarly, during the summer, the ground quickly warms up, and then as the weather gets cooler the ground begins to haemorrhage heat too.

The effect of all this is that during winter we have warm seas around us making our temperatures higher relative to say the USA and Russia. In turn we have less snow and less harsh winter conditions. During the summer months that same water which has chilled during the winter months now acts as a cooling influence allowing our summers to be cooler than say the USA and Russia.

More on the Gulf Stream … Sometimes factors skew the normal path of the Gulf Stream so that it bends further to the south during the winter months and so misses the UK altogether. When this occurs it gets cold really fast and we can expect a good dump of snow!

Where the weather comes from tells us lots …

Ok so knowing the above gives us a brief idea of what to expect if we know where the weather is coming from …  We know that to the north of the UK is the Arctic and to the south is Africa. So, if we have weather coming from the north we expect it to be cold and dry. From the south, warm and dry. If it comes from the west it will be wet. From the north-west, cold and wet and so on. If it’s summer and the weather comes from the east it will be hot and dry, and in the winter cold and dry.

As a rock climber I also use this information to help guide me and to get the best from a day on the crag on wet-weather days. I know that as the winds from the west push the air upwards over the hills and mountains that the air will no longer hold any moisture and it will fall as rain. This is because as the moist air is pushed uphill and as the air pressure decreases, clouds will form and the rain is released.

Hence, I know that often when it’s raining in the Peak District, that it could well be dry further to the east, closer to Sheffield. Similarly I know that if it is raining in the mountains of Snowdonia it could well be dry at Tremadog on the coast – since these crags lie much lower down and the rain is yet to be released.