Week by week weather conditions over the coming 46 days

Our extended-range forecasts provide an overview of potential weather conditions up to 46 days ahead, focussing mainly on average conditions week by week and how different they are from a long-term (model-based) climatology. For example, charts show if the average conditions over a week are predicted to be colder or warmer than normal for that time of year.

The extended-range forecasts are produced daily and have a horizontal resolution of around 36 km.

Find out more about how the extended-range forecast is produced.

Predictability in the extended range

The state of the oceans and the top part of the Earth's land masses can vary relatively slowly, providing a potential source of predictability in the extended range through their interaction with the atmosphere. Variations in the stratosphere may also play a role. In addition, the extended time range is  short enough that the atmosphere still has some memory of its initial conditions.