Birds fly by as the sun rises in Frankfurt, Germany, Monday, June 24, 2019. Germany expects hot temperatures during the next days. (AP Photo/Michael Probst)

PARIS (AP) — The sunset had an orange glow. So did the extreme weather warning for Paris.

Meteorologists placed more than half of France, including around the capital, on alert for high temperatures Monday as a heatwave was expected to spread across continental Europe this week.

National weather agency Meteo France predicted the hot weather could produce temperatures of up to 40 degrees Celsius (104 Ft) across the country just as the summer tourist season shifts into high gear.

The French weather agency set the heat warning level at orange - the second-highest intensity on its four-level categorization system for potentially dangerous conditions requiring public "vigilance."

In Paris, charity organizations patrolled the streets to provide homeless people with water, while local authorities organized air-conditioned public places where people could seek shelter from the heat.

French Education Minister Jean-Michel Blanquer, deciding it was too hot to study, ordered national exams taken by students heading to high school postponed from Thursday and Friday to next week.

International soccer federation FIFA could face implementing heat precautions at the Women's World Cup, which France is hosting. The precautions include holding cooling breaks during matches and postponing games if the heat is too intense.

Women's World Cup matches are scheduled every day this week, except Wednesday and Sunday. Luckily, most were set to be played at night.

France introduced a heat watch warning system after a long, deadly heatwave in August 2003. The highest temperatures in more than half a century eventually were estimated to have caused 15,000 heat-related deaths, many of older people left in city apartments and retirement homes without air conditioning.

French President Emmanuel Macron said Monday that vigilance was the watchword for the week.

"As you know, at times like these, sick people, pregnant women, infants and elderly people are the most vulnerable. So we must be vigilant with them and have prevention measures in place in order to intervene as quickly as possible," Macron said.

French Health Minister Agnes Buzyn said Monday that "everything is ready" in retirement homes, hospitals and transportation systems.

"Yet when people are fragile, even when everything is organized, there's always a higher mortality rate," she warned.

Meteorologists said hot winds from the Sahara Desert brought the scorching weather to Europe. Similar heat is expected in Belgium, Switzerland and Germany.

In Germany, temperatures above 40 degrees C are possible in some places on Wednesday, topping the country's previous June record of 38.2 degrees Celsius (nearly 100.8 degrees Fahrenheit) set in Frankfurt in 1947.

Rescue services urged people to look out for young children, the elderly and those with compromised immune systems who are at particular risk in high temperatures.

Parts of northeastern Germany are also at high risk for forest fires. Authorities in the eastern state of Brandenburg, which circles Berlin, say the risk of forest fires is at the highest level in the coming days.

Scientists say measurements show that heat waves in Europe are becoming more frequent.

Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research said "monthly heat records all over the globe occur five times as often today as they would in a stable climate."

"This increase in heat extremes is just as predicted by climate science as a consequence of global warming caused by the increasing greenhouse gases from burning coal, oil and gas," he added.

Dim Coumou, a scientist at the Free University of Amsterdam, said melting Arctic sea ice is also affecting atmospheric circulation, which in turn makes extreme heat more likely.

"Data analysis shows that the normally eastward travelling summer circulation of the Northern Hemisphere mid-latitudes has slowed down, including the Jet Stream," he said. "This favors the buildup of hot and dry conditions over the continent, sometimes turning a few sunny days into dangerous heat waves."

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Frank Jordans in Berlin contributed to the story.

A woman uses paper as a fan Monday, June 24, 2019 in Lille, northern France. Authorities in the Paris region have issued an alert for intense heat expected in the French capital and across Europe this week. Meteorologists say the heat wave is caused by hot winds coming from the Sahara desert. (AP Photo/Michel Spingler)
A dog sticks his tongue out Monday, June 24, 2019 in Lille, northern France. Authorities in the Paris region have issued an alert for intense heat expected in the French capital and across Europe this week. Meteorologists say the heat wave is caused by hot winds coming from the Sahara desert. (AP Photo/Michel Spingler)
A children plays and cool-off as water sprinkles from a fountain, in Milan, Italy, Monday, June 24, 2019. (AP Photo/Antonio Calanni)
Birds fly by as the sun rises in Frankfurt, Germany, Monday, June 24, 2019. Germany expects hot temperatures during the next days. (AP Photo/Michael Probst)
Sunflowers are pictured against the hot sun in Ravensburg, Germany, June 24, 2019. (Felix Kaestle/dpa via AP)
A woman sunbathes in a park Monday, June 24, 2019, in Lille, northern France.  Authorities in the Paris region have issued an alert for intense heat expected in the French capital and across much of Europe this week, with meteorologists reporting the heat wave is caused by hot winds coming from the Sahara desert. (AP Photo/Michel Spingler)
Poppies and wild flowers surround Whitburn Windmill near Sunderland, England, Sunday June 23, 2019. Recent wind and rain seems to have been swept aside to leave sunny calm weather, and hopes for a good summer still to come.(Owen Humphreys/PA via AP)
A dog sticks his tongue out Monday, June 24, 2019 in Lille, northern France. Authorities in the Paris region have issued an alert for intense heat expected in the French capital and across Europe this week. Meteorologists say the heat wave is caused by hot winds coming from the Sahara desert. (AP Photo/Michel Spingler)
Stand up paddle boarders explore the river Main in Frankfurt, Germany, on a warm and sunny Monday evening, June 24, 2019. (AP Photo/Michael Probst)