Cooling centres like City Hall Park's fountain in lower Manhattan have been kept open to help  beat the heat [AP]

A widespread heatwave is currently affecting much of North America.

Many parts of the USA have seen temperatures surge into the high 30s in recent days and this follows on from one of the hottest Junes on record (records go back over 100 years).

No less than 14 states recorded their top-10 hottest Junes this year.

The National Weather Service issued warnings for 24 states on Wednesday. An estimated 150 million people (almost half the population) are thought to be suffering from the searing heat and the death toll from the heatwave currently stands at 39.

Dallas experienced its 12th straight day of temperatures higher than 38C (that's 100F) on Wednesday.

Oklahoma City has now gone 15 days at or above 38C, while Phoenix has exceeded 34 consecutive days at that level.

A brief break is expected for parts of the Great Lakes, Northeast and mid-Atlantic over the next few days, but there is unlikely to be any relief for the southern states.

The heat even looks set to intensify across the Plains later this week and then expand into the Midwest.

Almost the entire country to the east of the Rockies is expected to see above average temperatures through next week. States such as Texas to Oklahoma could well see highs into the low 40s.

The heat and drought have led to record wildfire activity. The year-to date area burned nationally is at 5.8 million acres - the most on record for the period and almost twice the 10-year average.

On the other side of the Rockies there have been no such problems, in fact, California has just experienced its wettest June on record.

This has been welcome news across those burn areas around the Sierra Nevadas. Even now it remains cool and damp; the temperature in Los Angeles will struggle to reach 23C (around 5 degrees below average) over the next couple of days.

The areas in read are most affected by the severe heat and drought [NOAA]

The heat and drought have led to record wildfire activity. The year-to date area burned nationally is at 5.8 million acres - the most on record for the period and almost twice the 10-year average.

On the other side of the Rockies there have been no such problems, in fact, California has just experienced its wettest June on record. This has been welcome news across those burn areas around the Sierra Nevada.

Even now it remains cool and damp; the temperature in Los Angeles will struggle to reach 23C (around 5 degrees below average) over the next couple of days.