The area of Pedrógão Grande in central Portugal experienced the worst forest fire the country has ever experienced last week, killing at least 64 people and injuring many more. The blazes broke out on the afternoon of Saturday 17 June and spread rapidly, trapping people in their cars.

Some 350 soldiers and 1,600 firefighters battled the blaze, which is thought to have started from a dry thunderstorm triggered by the very hot, humid conditions of the days leading up to it as temperatures exceeded 40°C.

Not only was the ground dry but the rain falling from the large cumulonimbus clouds evaporated before reaching the ground. Lightning strikes ignited the fire and strong gusts of wind acted as a fan to enhance and spread it.

In contrast, there has been very heavy rain in New Zealand, flooding roads and trapping people in various settlements. Parts of the North Island had more than 70mm of rain in less than 12 hours. The area of low pressure responsible for bringing this spell of adverse winter weather continued to move southwards over the weekend, bringing plenty of rain to the South Island too.

Putting the recent UK hot spell in the shade, the south-western US has been experiencing severe heatwave conditions with 47C recorded in Las Vegas on 20 June – just one of the temperature records broken in the region.

This is due to a huge ridge of high pressure, associated with sinking air, trapping the heat being advected from the south. Excessive heat warnings have remained in place over the weekend, with seven fatalities being linked to the scorching weather.