There is no question that humans have and continue to alter the climate in and around cities. What has been more difficult to disentangle is the extent to which these changes confound regional and global assessment of climate variations and changes. Claims and counter-claims regarding the impact of urbanization abound, especially as related to the land surface temperature record. The extent to which these claims are consistent or inconsistent with ancillary information can be evaluated. Although much more limited in number, other analyses suggest that urban areas can modify precipitation events, also affecting our ability to interpret large-scale changes. Methods to evaluate precipitation-related inferences have not been fully developed, but will be explored.