GHCN HCN data shows that 1921 was the hottest January-October in US history. CO2 was 307 PPM at the time.
http://news.google.com/newspapers
20 Jul 1921 – DROUGHT IN BRITAIN. Unparalleled Heat Wave. LOND…
01 Nov 1921 – Record Heat Wave
06 Jun 1921 – FLOOD AND FIRE. COLORADO DISASTER. 1200 REPORTED…
http://trove.nla.gov.au/ndp/del/article/22613114?
