Skip to contentBack to top of page

Sub-seasonal weather forecasting project

Project highlights

We've improved weather forecasting to help predict business impact.   

A Piggy Bank

Ofwat project funding

£678,750

A handshake

Collaboration

We worked with eight partners

A clipboard

Project status

Completed in May 2025

Challenge: Adapting to increasingly extreme weather 

We faced challenges of increased frequency and severity of extreme weather events. This challenge highlighted the need for improved forecasting capabilities within the water industry. Traditional weather forecasts typically cover a 10-14 day period. However, longer-range predictions are crucial for effective planning and resource management.

Solution: Sub-seasonal forecasting for enhanced resilience

Our sub-seasonal weather forecasting project helped to:

Enhance understanding of how weather impacts water and wastewater management

Develop a reliable weather impact-based modelling and forecasting system. It will forecast impactful weather events up to 4-6 weeks ahead

Improve resource allocation and operational management in areas vulnerable to severe weather

More and more we are seeing the devastating impact of extreme weather events across the country. To help the water industry meet the challenges due to climate change, it is vital we have the tools to better forecast weather patterns and adapt our infrastructure and resources for the benefit of our customers
Ian Savage
Strategic Control Manager (London), Thames Water

How the project worked

The project was in partnership with the Met Office and other partner UK water companies. We used the Decider tool developed by the Met Office. It's a forecasting system that can be used to predict large-scale weather patterns over the UK.

By linking weather patterns to business impacts, we developed alerting tools. The tools can communicate potential risks. This enables more informed decision-making compared to relying on climatology or seasonal estimates. 

We've built on previously developed sub-seasonal water demand models. This will be tailored for each participating water company. 

In parallel, the project explored wastewater applications for sub-seasonal forecasting. It has developed a model that increases the predictability of alarm volumes. This is in order to improve operational management decision-making for wastewater. 

Timeline and collaboration

The project, funded by £678,750 from Ofwat involved eight partners and was completed in May 2025.

It underscores our proactive approach to managing weather-related challenges. Whilst also ensuring a reliable water and wastewater service for our customers.

Project resources