The heatwave has led to forest fires and droughts in parts of Europe popular with British tourists.
The Foreign and Commonwealth Office (FCO) has issued alerts about blazes in Spain, Portugal, France and Greece. Meanwhile, parts of Italy are suffering a drought that could lead to water shortages.
The UK Government is not advising people against travelling to the countries. But it is reminding holidaymakers to take care, precautions and to be prepared for disruption.
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Spain
More than 30 forest fires around Spain have forced the evacuation of thousands of people and blackened 220 square kilometres (85 square miles) of forest and scrub.
Teresa Ribera, Spain’s minister for ecological transition, described her country as “literally under fire” as she attended talks on climate change in Berlin.
She warned of “terrifying prospects still for the days to come” — after more than 10 days of temperatures over 40C (104F), cooling only moderately at night.
At least 748 heat-related deaths have been reported in the heatwave in Spain and neighbouring Portugal, where temperatures reached 47C (117F) earlier this month.
The FCO says: "There is currently a heightened risk of forest fires due to exceptionally high temperatures in Spain. Take care when visiting or driving through woodland areas. Access to some areas such as natural parks and nature reserves may be limited or closed as a result. You should follow the instructions of local authorities and call 112 if you need emergency assistance."
It adds: "Forest fires occur frequently in Spain (including Spanish islands) during the summer months, when temperatures regularly reach over 40ºC. Take care when visiting or driving through woodland areas.
"Causing a forest fire is considered a criminal offence in Spain even if unintentional. Make sure cigarette ends are properly extinguished, don’t light barbecues and don’t leave empty bottles behind. There are strict regulations across much of Spain against lighting outdoor barbecues in forest areas and penalties imposed include heavy fines. Some regions prohibit the use of outdoor barbecues in public picnic areas during the summer months.
"Check on the outbreak of fires with the local civil protection authority and report any you see immediately to the emergency services on 112."
Portugal
Recent cooler weather has helped Portugal tackle wildfires. More than 600 firefighters were deployed to four large blazes earlier this week. However, there is a risk hotter weather could return and lead to more.
Portugal remains in a state of alert, the FCO says, which may mean there are bans on where people can go.
It adds: "Forest fires can occur anywhere in Portugal during the summer months. In recent years, fires have become more frequent due to drought and high temperatures. Forest fires are highly dangerous and unpredictable. The Portuguese authorities may evacuate areas and close roads for safety reasons."
France
More than 31,000 have been evacuated from France's Gironde region since wildfires began on July 12. Road closures are in place and access to forests in Gironde is forbidden
The FCO adds: "Forest fires can occur anywhere in southern France during the summer months but especially along the Mediterranean coast and in Corsica. In recent years, fires have become more frequent due to drought and high temperatures. French Authorities may evacuate areas and close roads for safety reasons. If you’re staying in a high-risk area you should familiarise yourself with the local safety and emergency procedures, be vigilant and follow the advice of local authorities."
Italy
There is a risk of forest fires in Italy. The heatwave has also caused a water shortage.
The FCO says: "Parts of Italy, especially in the north, are currently facing a severe drought and may see water rationing.
It adds: "Forest fires are a risk during the extended summer months. Forest fires are highly dangerous and unpredictable; check with local authorities if you’re considering travelling to affected areas. Take care when visiting or driving through woodland areas and report fires to the emergency services."
Greece
There are wildfires to the north of Greece's capital, Athens. Evacuation orders have been issued for Ntrafi, Dioni, Dasamari, and Anthousa, and instructions to remain on high alert issued for Penteli, Ntaou Pentelis, and Kallitexnoupolia, the FCO says.
The FCO advises: "Forest fires often occur during the summer months across Greece due to the dry/hot weather.
Forest fires are highly dangerous and unpredictable. Take care when visiting or driving through woodland areas. Make sure cigarette ends are properly extinguished and don’t light barbecues."
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