Finns and Saudis might well be the last survivors if the world's temperature went in either extreme points. Both nations have ultimate endurance for cold/heat.
Here is a temperature table I created to illustrate how the Saudis and Finns would deal with such extremes:
+1063 C Gold starts melting. Saudi women take off their abayas.
+600 C Crude oil reaches boiling point. Saudis are happy they no longer need oil refineries.
Saudi camels complain of the burnt taste of the grass.
The swimming pools in Saudi-Arabia now have warm water in them.
The only other surviving humans are Yemeni bedouins who covered themselves in mud and hid in the mountains.
+70 C The Saudis have changed to summer abayas and thobes.
The rest of the world has immigrated to Antarctica.
The Saudi camels ask to get shaved for the summer.
+60 C Saudis lower their car windows for a fresh breeze.
Saudi camels are enjoying the crisp air.
+45 C Saudis feel comfortable and have turned the heaters off. The weather is nice and cool for spring, time to plant some flowers and go camping in the desert.
The Spaniards all flock to the Alps.
+35 C The remaining survivors of the heat wave in Finland die.
The Saudis change into their winter thobes and abayas.
Saudi camels complain of the draft in the desert.
+25 C A heat wave warning is issued in Finland. Finns start to die from the heat stroke. Clothing has been shed off and Finns are naked.
Saudi camels start growing their winter coats. Saudis turn their heaters on.
+20 C The Finnish people are starting to get uncomfortable. They have shed all their clothing down to bathing suits to cope with the heat.
Saudis no longer venture out of their heated homes where they sit in their farwas (furs). The camels complain of frost on the grass.
The Finns are sunbathing.
The Saudis start lighting bonfires inside their living rooms in order to survive the cold.
Finnish cows are shaved and fed grass popsicles to cope with the heat.
The Finns are planting flowers in their gardens.
Saudis start dying of cold weather.
The French are eating frozen baguettes.
The Finns are still driving their motorcycles in shorts.
The Italians are all migrating to Sardinia.
Saudis become an extinct race.
Water freezes. The rivers in Finland flow a little bit slower than normal. Finnish cows are let out to the meadows.
Swedes turn on their heaters.
The Finns are having the last barbecue parties of the season.
The English farmers are finally putting their heaters on.
The Finns are putting on long sleeved sweaters.
Eskimos move to their winter igloos.
Finnish cows are enjoying the fresh air.
The Finns are getting ready for fall and are putting jackets on. Finnish babies are enjoying sleeping outside in their strollers.
The Greeks die of cold after having to eat frozen feta cheese.
The Finns start drying their clothes inside. Finnish cows are taken into the barn for winter.
The Swedes have all moved into their fake saunas and are drinking Absolute vodka to warm up.
The Finns are standing in line at the sausage stands. Finnish children are enjoying playing in the snow.
Russians have all fled to Egypt.
The Finnish army is postponing their survival camp until the weather is cold enough. Finns turn on the seat-warmers in their cars.
The Swedish fake saunas no longer function.
The Finnish army leaves to winter camp.
The polar bears start evacuating Antarctis. The Finns get frustrated because they can no longer cool their alcohol outside.
The Finnish cows complain about cold hands when they are getting milked. The few other surviving humans are Russians who accidentally drank liquid nitrogen mistaking it for vodka.
Every movement in the atomical level stops.
The Finns are putting on wintercoats and cursing the cold weather.
Hell freezes over. Team Finland wins the football World Cup.