The variation of temperature and relative humidity throughout the world is discussed. Environments occurring at location where museums are most likely to exist are included as well as the extremes in environments that might be encountered while paintings are in transit. The internal environments of trucks, trains, aircraft, and ships are examined with a discussion of the factors that affect the temperature and relative humidity of those environments. This paper also includes a section on environmentally controlled transport and the degrees to which protection is provided. The results of monitoring actual painting transport is reported.