The thermal climate in Moscow was studied for 1990. Air temperatures near the surface were analysed for a number of locations representing different land‒use types. The urban–rural temperature differences ranged mainly between 1° and 3°C, with an absolute maximum of 9·8°C. In summer, the heat island intensity exceeded 3°C on 29 per cent of all early morning observations, confirming the widely held view that anticyclonic conditions generate strong heat islands. Temperature variations within the city were small, with a notable exception of the urban park; in winter, the lee periphery of the city was often warmer than the urban centre. Vertical temperature profiles in the lowest 500—14m were studied using data obtained at the Ostankino TV tower at seven levels. Although the daytime profiles throughout the year and the nocturnal profiles in winter confirmed observations elsewhere, the nocturnal summer profiles were unlike those registered in other urban areas with an unexpectedly high frequency of strong ground‒based inversions. In July and August, ground‒based inversions were registered on 57 per cent of all nocturnal observations. This phenomenon can be explained by the ‘open’ street geometry that is typical of Moscow and a reduced (in comparison with winter) input of artificial heat. ©1997 Royal Meteorological Society. INt.J.Climatol., Vol. 17, 1451-1465 (No. of Figures:8 No. of Tables: 5 No. of