Like most of northwestern Europe, the climate in the United Kingdom is defined as a temperate oceanic climate, consisting of four distinct seasons of fairly equal length - spring, summer, autumn and winter. As this island country is surrounded by seas, it has a varied climate which is hard to predict, meaning that the weather often changes from day to day. It can be sunny one day and rainy the next. In general, the UK has warm summers and cool winters.

There are several important factors that affect the weather in this part of Europe. The summer, which is cooler than in other European countries, is mainly influenced by the northern latitude and close proximity to the Atlantic Ocean. These conditions don't allow summers to be so hot. The winter is influenced by the Gulf Stream. It is warming the waters around the land, making the weather hotter than the average in this part of the world.

Regarding the regional climate differences in the United Kingdom, they can be easily separated in to 4 main groups:

- north west - cool summers, mild winters, heavy rain all year
- north east - cool summers, cold winters, steady rain all year
- south east - warm summers, mild winters, light rain all year, especially summer
- south west - warm summers, mild winters, heavy rain all year, especially winter

These weather differences depend on the latitude of the region and the surrounding waters. The latitude highly affects the climate, making it hotter in the south and colder in the north. The western region faces the Celtic Sea and the Irish Sea, the eastern region looks towards the Northern Sea, the northern region is surrounded by the North Atlantic Ocean, and the south is bordered by the English Channel.

Northern Ireland and the west of Scotland are the most exposed to the maritime polar air mass which brings cool moist air; the east of Scotland and north-east England are more exposed to the continental polar air mass which brings cold dry air; the south and south-east of England are more exposed to the continental tropical air mass which brings warm dry air; and Wales and the south-west of England are the most exposed to the maritime tropical air mass which brings warm moist air.

With this temperate maritime climate, the United Kingdom has temperatures not much lower than 0ºC in winter and not much higher than 32ºC in summer. Average yearly temperatures at low altitude vary from 7°C in Shetland, in northern Scotland, to 11°C on the south-west coast of England. The coldest place is Ben Nevis where the average temperature is less than 0°C. The coldest months are January and February and the warmest are July and August. In general, in Scotland and Northern Ireland, the summer is about 3°C cooler than in England and Wales.

Rainfall

The rainfall in the United Kingdom depends on the season, but in general, it's one of the wettest countries in Europe, having a seasonal amount of rain in northern regions larger than the annual amount in some Mediterranean countries. It is fairly well distributed throughout the year. The driest period of the year is late winter/early spring, especially in February and March. The period with the most rainfall is autumn/winter, from October to January. The wettest region in England is the Lake District, with an average of 330 centimeters of precipitation each year. The western and northern parts of England receive about 102 centimeters of rain, while the east coast has the smallest amount with an average of 51 centimeters.

Humidity

Even though the rainfall in U.K. is high, the humidity in this country is not as high as might be expected. This is mostly because there are no extremely hot summer temperatures. The average annual humidity goes from 70% in southern England, which is the lowest, to 92% in the central and northern parts of the UK.

Clothing

As the country with the most unpredictable day to day weather, there is no general clothing norm for different seasons. The top recommendation for anyone visiting Great Britain would definitely be layering. The smartest way to cope with this uncertain weather is to prepare both short-sleeved and long-sleeved T-shirts, jumpers and a coat. This way, you can easily put them together in different ways and take them off, if needed. Raincoats and umbrellas are useful items to carry in this rainy country.

Environmental risks in the UK

The United Kingdom has no serious weather or environmental risks. This part of the globe is not known for hurricanes, tsunamis or earthquakes like in eastern Asia or North America. There are no active volcanoes in United Kingdom either. In general, Europe doesn't have any huge environmental risks. The only country that has some active volcanoes is Iceland, which is situated in the middle of two tectonic plates.