Answers are grounded in this paper and cite their sources.
Meteorological stations located in an urban environment in North America warmed between 1941 and 1980, compared to the countryside, at an average rate of about 0.12°C per decade. Secular trends of surface air temperature computed predominately from such station data are likely to have a serious warm bias.
No takes yet. Share an insight, caveat, or question.
Kukla et al. (1986) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: