With all the recent interest in cold and snow I thought it might be interesting to revisit the three coldest years that North-Central and Eastern Europe experienced in the 20th century, which occurred one after the other in 1940, 1941 and 1942. The graph below shows the 20th century temperature records for three widely-separated cities in the affected region – Helsinki, Kiev and Vienna. The three successive cold years show up as an anomalous feature on all of them. I briefly toyed with the idea that these cold years might have been caused by the war (blackouts, curfews, fuel rationing etc = lower UHI impact) but it didn’t fit. Then with the graph below the cause became apparent. The jumbo-sized 1940-41 El Niño was the culprit. If the 1940-41 El Niño really did cause the abnormally cold 1941-42 Russian winter it may well have altered the outcome of the Second World War.