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Climate model outputs are typically arranged in a regular grid format. Each grid is characterised by its spatial bounds (what area it covers) and its resolution (how big each grid square is). UKCP09 probabilistic projections are available at a grid resolution of 25 km.

In detail

The HadRM3 has been used to downscale the global climate simulations to a spatial resolution better suited to impacts and adaptation assessments. This RCM operates at 25 km resolution.

The UKCP09 25 km grid has a rotated pole meaning that the grid orientation appears to be rotated anti-clockwise relative to true north. Each grid square is approximately 25 km x 25 km in size and is either assigned as land or sea. In total there are 434 land grid squares that define the UK and for which probabilistic climate projections are available.

Other UKCP09 data sources have different grid resolutions. The different grids used in UKCP09 are:

  • 25 km grid - The grid used by HadRM3 for UKCP09 probabilistic projections and observed baseline dataset.
  • 5 km - The grid used for the UKCP09 Weather Generator and observed climate dataset.
  • 12 km - The grid used for projections of sea level rise.
  • 12 km - The grid used by POLCOMS for multi-level ocean projections.
  • 12km - The grid used by POLCS3 for projections of changes in storm surge levels

Find out more


  • The UKCP09 25 km grid is displayed in  of the UKCP09 Briefing report.
  • Projections are provided for every 25 km grid square. A single grid square location is one of the elements that can be specified when building a request in the  UKCP09 User Interface .