Although the UK is barely the size of Florida, its weather can be more varied on one day than the weather over the entire United States. This is due to its geographical location, just off the north west coast of mainland Europe and being completely surrounded by the various branches of the Atlantic Ocean. The weather in the UK can be influenced from any direction at any time, though the weather can be generally placed into four categories:
- Tropical Maritime, wind SSW-W (the prevailing influence on UK weather stemming from the North Atlantic Drift, an extension of the Gulf Stream; weather is mild to hot and can be wet.)
- Polar Maritime, wind W-NNW (this weather comes from Northern Canada and Greenland. Usually brings cold, wet and often windy weather, snow is a distinct possibility in winter and spring, though it tends to only fall in upland northern regions)
- Polar, wind NNW-NE (direct from the Arctic, almost always occurs in winter, this influence will bring some snowfall across most of the country; accumulations are highest in Scotland and North-East England)
- Continental, NE-SSW (a mixed bag really, in summer, this is a pleasant airflow and brings hot, dry weather. In winter, it is very cold and dry, although the eastern coast will see snow flurries)
Winter (late November to mid March) - temperatures range from -15C in the north to 10C in the south west, though with windchill, it can feel colder. Indoor shopping malls and entertainment centres are the order of the season, though in dry spells, outdoor Christmas markets and a crisp walk through a forest are experiences you'll not want to miss. Typical winter clothing should keep you right: woolly hats, warm overcoats and gloves.
It is ill-advised to fell walk or mountain climb in this season as temperatures drop sharply at higher altitudes and daylight is at a premium. Storms, with torrential rain, the occasional blizzard and winds up to 70mph (110kmh) occur most every winter, usually in January. Be prepared for the nation coming to a halt when there is snow; many trains don't run, cars have no winter tyres and slide all over the place, schools close!
Spring (late March to late May) - Often wet and mild, but in between the rain showers, things can get warmer. Typical temperatures range from 5C to 20C. Harsh winter "kick-backs" can occur as can blasts of warmer weather from the Sahara but overall, no real extremes of weather happen. May tends to be the most settled month of the year, a good time to visit too, with nature in full swing and the tourist season still a couple of months off.
Summer (early June to mid September) - For the most part, Summer is warm, quite dry and the best time to visit the UK if you're after reliable weather and an outdoor holiday. Temperatures stay above 15C by day (usually dipping no lower than 10C by night) over the entire UK and can exceed 35C in a heatwave. If the humidity index rises sharply, it is almost a sure sign of an imminent summer thunderstorm, which can be fairly spectacular; 100mm of rain can fall in 30 minutes or less. July 2006 was the hottest month ever recorded in the UK, with the average temperature, both day and night, being 17.8C, way above the 14C average. Schools finish for summer mid July in England and at the end of June in Scotland. All universities finish mid June.
To avoid the crowds and still get warm weather, early to mid June is your best bet. Daylight hours are long too; owing to the latitude, places from Manchester northwards get no darker than twilight for 6 weeks either side of the solstice (21st June). Up in the Shetland Islands, situated at 60 degrees North, there is no proper darkness between mid-May and early August and they play golf at midnight at midsummer.
Autumn (late September to mid November) - A changeable season, but it's the UK at its most picturesque. The colours of the leaves are on par with those seen in New England and are only enhanced with an "Indian Summer". Weather from the south west is generally not great news at this time of year as it brings remnants of hurricanes from the south-east USA and Caribbean, winds of 60mph (100kmh) and heavy rain being the situation. October 1987 saw a Category 3 hurricane hit the south of the UK, with sustained winds of 105mph. Extensive damage occurred and 18 deaths were reported. Be prepared for many trains to be delayed due to leaves on the tracks [it's not a joke]
There you have it! The UK's weather in a nutshell! Basically, every season has its highs and lows, April to early October is the best period to visit. If, however, you want some exciting weather, any other time of the year is good too.
Check the BBC's website for in-depth 5 day forecasts for any UK destination.