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The term 'seasonal' refers to one of the averaging periods for which climate changes projections are provided in UKCP09. Each season represents a 3-month period.

In detail

The term 'seasonal climate' is used to describe conditions either averaged (e.g. for temperature) or totalled (e.g. for rainfall) across a seasonal (3 month) period.

Climatological convention dictates the months that fall into a particular season. These are Northern hemisphere definitions only:

  • Winter: December, January and February (DJF)
  • Spring: March, April and May (MAM)
  • Summer: June, July and August (JJA)
  • Autumn (Fall): September, October and November (SON)

Find out more


  • Graphs of recent observed changes in seasonal climate are provided in Chapter 2 of the UKCP09 Observed Trends report.
  • Projected future changes in seasonal climate are provided in the UKCP09 Briefing Report for mean daily maximum temperature and for changes in precipitation (the average total precipitation in summer and winter). Further details on projected changes in seasonal climate are given in the UKCP09 Climate change projections report.
  • Some key findings associated with seasonal changes are reported for the UK as a whole and for UKCP09 administrative regions.
  • Results are also available as maps for the UK as a whole and for UKCP09 administrative regions.
  • Customised graphical outputs relating to projections of changes in seasonal climate conditions can be obtained using the UKCP09 User Interface.