Although UK weather is unpredictable, it is rarely extreme. In summer, the average temperature ranges from 9–18 degrees Celsius (48–64 degrees Fahrenheit). On occasion, it can reach around 30 degrees Celsius (86 degrees Fahrenheit) in a heatwave.
In winter the average is between 2 and 7 degrees Celsius (36–45 degrees Fahrenheit), but temperatures often drop to just below 0 degrees Celsius (36 degrees Fahrenheit). Thankfully, most houses, buildings, trains and buses have good heating systems.
In general there is little difference between the regions of the UK, but you will experience more snow, rain and wind the further north you go and/or in mountainous areas.