Testing TOBS by station removal is a little tricky because morning stations tend to be in warmer parts of the country, so diverging regional trends affect the result. But one state had a 50/50 mix of morning/afternoon stations in July 1936.
There are 26 HCN stations in Missouri and 13 of them took readings either at morning or night during July, 1936. These 13 stations would tend to be biased cold in the 1930’s according to TOBS theory.
I compared the cold stations vs. all stations, and there is essentially no difference. TOBS is 99% BS.
Based largely on their phony TOBS adjustment, NCDC turns a cooling trend in Missouri into a warming trend.
Here is the list of morning/night stations from July, 1936
APPLETON CITY MO USC00230204 CLINTON MO USC00231711 FARMINGTON MO USC00232809 JEFFERSON CITY WTP MO USC00234271 LAMAR 2W MO USC00234705 LEBANON 2W MO USC00234825 LEES SUMMIT REED WR MO USC00234850 LEXINGTON 3E MO USC00234904 MEXICO MO USC00235541 MOBERLY MO USC00235671 MTN GROVE 2 N MO USC00235834 SPICKARD 7 W MO USC00237963 UNIONVILLE MO USC00238523