Radio 4 are trying a new format of weather forecast. Previously, I’d always found it hard to take in the information whilst listening to the forecast on my way to work, but never really thought about why this was.

Apparently, a listener complained that it was hard to absorb, and this triggered the team thinking. One experiment was to read the national forecast in the style of the shipping forecast, one area at a time. This devastatingly simple idea cuts straight to the core of the problem with the old-style forecast: attention span.

The information being presented is essentially two-dimensional: spatial (which is a single dimension, as the regions are effectively a list) and temporal (the time of the forecast). Being an audio broadcast, the data flow of the delivered forecast is one-dimensional (time), so a route must be planned through the 2D data set to stream it to the listener.

With the old format of presentation, the listener is taken on a journey through time-of-day in discrete blocks (morning, afternoon, evening etc.), with the major weather phenomena described, usually in some sort of regional order. The time “axis” is only traversed once. We can represent this as below, with the delivery of the forecast following the red path. I’ve taken the part of a Middle-dwelling listener, with the bits I care about highlighted in green:

If we unwrap the ground covered by the red path, we get a sequence of information showing where the listener does and doesn’t care about the data. I’ll call this a care-now map, as that definitely won’t get confused with any other type of diagram. Here’s the old-format care-now map:

Suddenly, it’s clear why I find the weather forecast so hard to take in! It’s asking for many little snippets of my attention — by the time I’ve realized and started listening, they’ve moved on to the next region.

The new format, however, is much more logical. The listener is taken through the forecast time span multiple times, once per region, with regions combined as appropriate if the same weather conditions apply. Here’s the path taken through the data: it’s orthogonal to the old way:

…and the care-now map:

Much better. I can ignore the bits I don’t care about, and listen to the bit I do want to hear in one continuous section. Well done to whoever came up with this idea, and I look forward to this new format extending to all radio weather forecasts.