Ocean heat wave a sign of worsening climate change, study says, page-12

is there any actual evidence of recorded temperatures in say i dont know pick 12 or so random cities in the world
say for example

New York
Los Angeles
Rio
Sydney
Cape Town
Shanghai
Singapore
New Delhi
Moscow
Rome
Lagos
Madrid (or pick your own)

for say a 100 year period from early 1900's to current day?

this i would be interested in.

when people put some maps of the world and cover it in red splodges and say "these areas" had the hottest year on record, its like really?

how do you actually know?