Unusually hot weather is gripping parts of the United Kingdom this week, prompting heatwave alerts from authorities until Thursday. The UK Met Office's has issued a level three amber alert for heatwave conditions in central England until mid-week, and southern parts of the country until Thursday morning. This alert level is one step below a National Emergency and comes into force when two days in the low thirties bookend a night in the mid-to-high teens. In a climate zone like Australia's it can be difficult to accept that a string of days in the low thirties constitutes a heatwave. To understand why this may be inconceivable, one only needs to look at some of the recent heatwaves in Australia. A prolonged spell of heat last summer saw Moree and Mungindi register more than 50 consecutive days at or above 35 degrees, both breaking the previous record for New South Wales. Mungindi endured 15 days in a row above 40 degrees during this oppressive run of heat and ended up with 41 days over 40 degrees in the first two months of 2017. Other impressive temperatures seen earlier this year included a top of 48.2 degrees at Tarcoola in South Australia on February 9th (a new late-summer record) and an overnight minimum of 34.2 degrees at White cliffs in New South Wales on February 11th (state's highest minimum ever recorded). Richmond, a suburb of Sydney, reached a sweltering 47 degrees on February 11th, setting a new monthly record for the Sydney Basin. Looking further back and higher up the scale, the highest temperature ever recorded in Australia was 50.7 degrees at Oodnadatta, on January 2nd 1960. However, despite the long list of extreme temperatures in our sunburnt country's past, this week's weather in the UK is still a heatwave. While the definition of a 'heatwave' differs throughout the world, the term is used in Australia and the UK to describe an extended period of hot weather relative to the expected conditions at that time of year that is likely to affect people's health and wellbeing. A southerly change is expected to sweep through England by Friday, bringing an end to the heatwave. London is forecast to reach tops of 21 degrees from Friday into the weekend. While this may seem mild for an early summer's day in Australia, it's right on average for this time of year in London. The current world record for the highest temperature is 56.7 degrees, which occurred at Furnace Creek in California, USA on July 10th 1913.