How accurate are we?

We have an open and transparent policy on how we verify the accuracy of our forecasts.

Forecast verification

Verification is needed to measure how we are doing against the Key Performance Targets (KPT) for forecast accuracy, as set by government. These KPTs are part of our ongoing long-term commitment to improving the accuracy of our forecasts to the public. We will do this by reaching accuracy targets set for:

• Probability of precipation forecast, for the next day and the day after, for 139 places within the UK (Met Office observing sites).
• Temperature forecasts, for the next day and the day after, are assessed at the same sites as the probability of precipitation forecasts.
• The forecasting skill of our computer models

The following graphs show how we are doing against the Key Performance Targets.

UK computer model forecast accuracy

Global computer model forecast accuracy

UK temperature

UK rainfall

How we are doing

This table shows the Key Performance Targets for 2009/10

Measure	Target for 2009/10	Value at September 2009	Achieved/ not achieved
UK Index	117.0	118.3	To be assessed on 31 March 2010
Global Index	138.1	136.9
UK Temperature Index	0.666	0.666
UK Precipitation Index	0.267	0.255

How we did last year

This table shows how we did against the Key Performance Targets for 2008/9

Measure	Target for 2008/9	Value at March 2009	Achieved/ not achieved
11 cities maximum temperature	86.2%	86.8%	Achieved
11 cities minimum temperature	84.4%	84.9%	Achieved
11 cities probability of precipitation	0.438	0.421	Not achieved
Numerical Weather Prediction Index	125.8	125.8	Achieved