Suffering under the worst heat wave in more than six decades, Argentina has issued health warnings to nine southern and central provinces, the National Meteorological Service, said Saturday.

This is the eighth heatwave to hit the country in this Southern Hemisphere summer, with temperatures close to 40 Celsius (104 Fahrenheit).

Over the past decade, Argentina has never seen more than four or five such heat waves per season, the SMN said.

The three months from November through January were the warmest such period since 1961 -- about 1.7 C higher than normal, the weather service said.

While occasional heat waves are normal, climate change has made them "more persistent and more intense" on every continent, even in Argentina's mountainous Patagonia region, meteorologist Enzo Campetella told AFP.

Buenos Aires residents awoke Saturday to temperatures of 36 C with a predicted high of 38 C, which would be the highest in February in 61 years.

The SMN issued an "orange alert" Saturday for the provinces of Corrientes, Misiones, San Luis, Mendoza, La Pampa and Buenos Aires, as well as a "yellow alert" for Cordoba, Entre Rios and San Juan.

In Patagonia, temperatures hit 42 C on Thursday along the coast of Rio Negro province, but shifting winds brought welcome cooling.

The La Nina cycle of the El Nino weather phenomenon brought historically high temperatures throughout Argentina last year, leading to crop losses estimated at some $10 billion, according to the Rosario Grain Exchange.