British and French authorities have issued health warnings related to hot weather this weekend as northern Europe bakes under an early summer heat wave.

Temperatures are forecast to peak at 34 degrees Celsius in parts of eastern England on Saturday following a week of unusually warm weather, according to the Met Office, Britain's national weather agency. That's about 12 degrees C higher than normal for this time of year.

It's expected to be even hotter in France, where forecasters said temperatures are likely to reach 38 C in western and southern parts of the country.

The UK Health Security Agency and the Met Office issued an amber heat health alert covering all of England through Monday morning due to increased health risks for people over 65 and those with heart and lung problems.

“Heat can result in serious health outcomes across the population, especially for older adults or those with pre-existing health conditions,” Dr Agostinho Sousa, UKHSA's head of extreme event health protection, said in a statement. “It is therefore important to check on friends, family and neighbours who are more vulnerable and to take sensible precautions while enjoying the sun.”

France's national weather agency, Meteo France, issued a similar warning for western and central parts of the country, cautioning that high temperatures put “everyone at risk, even healthy people.”

The impact of the weather could be seen earlier this week at the Paris Air Show, where aviation enthusiasts took shelter under the wing of a Boeing 777 as temperatures hovered in the low 30s C

British forecasters said Saturday is expected to be the hottest day of the heat wave, with temperatures falling slightly on Sunday before dropping back into a more normal range next week.

Aviation enthusiasts attending the Paris Air Show at Le Bourget airport north of the capital earlier this week sought shade under the wing of a Boeing 777 as temperatures hovered in the low 30s C.

In the Netherlands, organizers of Amsterdam's 750th birthday party have set up additional water stations and reduced ticket numbers in anticipation of Saturday's high temperatures. Officials said they were worried the heat would be magnified by the asphalt surface of the ring road where the event will take place.

Elsewhere in the Netherlands, events from marathons to concerts have been cancelled. The Philzuid symphony orchestra scrapped several outdoor performances in the southern city of Eindhoven out of concerns the high temperatures could damage their instruments.

Such warnings are becoming increasingly common across Europe as global warming boosts temperatures.

Met Office scientists this week published research showing that climate change is increasing the likelihood of extreme high temperatures in the UK. The chance of temperatures exceeding 40 degrees Celsius is now more than 20 times higher than it was in the 1960s, the researchers said.