About the average global temperature maps

Analyses available

Global average temperature maps are available for annual and seasonal temperature. Long-term averages have been calculated over the standard 30-year period 1961-1990. A 30-year period is used as it acts to largely smooth out the year-to-year variations of climate.

Interpreting the analyses

The average temperature maps can be used in conjunction with the temperature trend maps to provide an indication of how a trend compares to the long-term average. For example, what might seem like a large trend in a particular region might not be all that significant if the average temperature is high.

Data used

The average maps are based on the Climatic Research Unit HadCRUT3v global gridded (5x5 degree resolution) absolute temperature data set for the base period 1961-1990 (see Brohan et al, 2006) developed by the Climatic Research Unit (CRU) at the University of East Anglia, in conjunction with the Hadley Centre of the UK Met Office. This data set replaces the older HadCRUT2v (see Jones et al, 1999) which is no longer being updated.

Please note that any use of these data should be acknowledged to the Bureau of Meteorology and the institutions listed above. Apart from the purposes of study, research, criticism and review, no part of these data may be reproduced, or redistributed for any commercial purposes, or distributed to a third party for such purpose, without written permission from the Director of Meteorology.

Further information

Brohan, P., J.J. Kennedy, I. Haris, S.F.B. Tett and P.D. Jones, 2006. Uncertainty estimates in regional and global observed temperature changes: a new dataset from 1850. J. Geophysical Research 111, D12106, doi:10.1029/2005JD006548

Jones, P.D., New, M., Parker, D.E., Martin, S. and Rigor, I.G., 1999. Surface air temperature and its variations over the last 150 years. Reviews of Geophysics 37, 173-199.