Urban Heat Island Effect in NYC up to 8°C

from CO2science.org:

...the heat island signal, measured as the difference between the urban core and the surrounding rural surface air temperature readings taken at National Weather Service stations, averages ~4°C on summer nights (Kirkpatrick and Shulman, 1987; Gedzelman et al., 2003; Gaffin et al., 2008)," with the greatest temperature differences typically being sustained "between midnight and 0500 Eastern Standard Time (EST; Gaffin et al., 2008)." And on a day that they studied quite intensively (14 August 2002), they report that at 0600 EST, "the city was several degrees warmer than the suburbs, and up to 8°C warmer than rural areas within 100 km of the city." ...