Seasonal Normal Review Update

Our Demand Estimation Team provides an update on the ongoing work as part of the Seasonal Normal Review.

Published on 24 Oct 2019

Our Demand Estimation Team is pleased to be able to provide our customers with an update on the progress of the Seasonal Normal Review. Their update contains a helpful introduction into the Seasonal Normal Review and Composite Weather Variable, updates on the key industry milestone achieved in October and a look ahead towards next steps.

Seasonal Normal Review - October Update

Last updated on 24 Oct 2019

What is the Seasonal Normal Review, and why is it important?

The ability to estimate gas consumption is critical to a range of calculations across the gas industry. These may be at a daily level such as Non-Daily Metered (NDM) allocation, or at an annual level such as Annual Quantity (AQ) calculations. They can even be at a theoretical level, for example when trying to estimate the peak consumption of gas during extreme cold weather events as part of Supply Offtake Quantity (SOQ) calculations.

Every day consumption goes up or down and there will be many reasons why, some of which are complex and some are more predictable. Unsurprisingly gas consumption has a very strong correlation with weather and consequently, many years ago, the industry created its own unique weather data item which is designed to explain this key relationship - the Composite Weather Variable (CWV).

The Composite Weather Variable (CWV), which represents actual weather, and the Seasonal Normal Composite Weather Variable (SNCWV), which represents the industry’s view of ‘normal’ weather, help us estimate gas consumption throughout the year.

To ensure these data items continue to provide the industry with an accurate reflection of gas consumption across the year, our Demand Estimation Team is overseeing the ‘Seasonal Normal Review’, a deliverable focussed on the suitability of the CWV and SNCWV to represent latest gas consumption behaviours and levels.

Read our update and find out more

You can read the full update here, and you can also find more information on the work of our Demand Estimation Team, including frequently asked questions on key topics, on the Demand Estimation page of our website.

If you have any questions or comments on the Seasonal Normal Review, please contact us at