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Time period

A period of 30 years over which climate averages are calculated.

In detail

UKCP09 uses 30-year time periods for both the baseline climate and for all future climate projections. The projections are reported for seven overlapping 30-year time periods. Each future time period is named based on the decade upon which it is centred.

UKCP09 time periods:

  • 1961 to 1990 – the baseline period 
  • 2010 to 2039 – the 2020s;
  • 2020 to 2049 – the 2030s;
  • 2030 to 2059 – the 2040s;
  • 2040 to 2069 – the 2050s;
  • 2050 to 2079 – the 2060s;
  • 2060 to 2089 – the 2070s;
  • 2070 to 2099 – the 2080s
  • This is shown graphically in Figure 1.3 of the UKCP09 Climate change projections report.


  • More details about the baseline climate of the UK, including regional differences, are given in the UKCP09 Observed trends report.

  • The implications of user choices are discussed in Chapter 4.4 of the UKCP09 Climate change projections report.

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