Romance has lived too long upon this river; a single-serving web page that tells you how high the tide is at London Bridge: explicitly close up, but also, roughly, at a glance.
The scale runs from zero metres (low tide is typically around 1m deep at London Bridge) to 7.6m (this is around the peak for Spring tides, so if the water fills the screen you know it’s a big one).
The Thames and its related activities are of course the Hello World of real-time data, but I also wanted this to be useful. So Romance… also serves as a weather forecast, warning you if you need to wrap up or take a brolly when you go out.
The weight of the clouds on the water corresponds to the chance of rain (or, fingers crossed, snow). It’s quite subtle, and it may need to be beefed up, but if it’s on your wall, or in your hand, you may, over time, develop the ability to sense the weather.
Update 8/5/11: Originally, the site was powered by the BBC's predicted tide tables. In early 2011, the BBC changed the way they reported this data, breaking the site. As of May 2011, the site now uses directly observed Port of London Authority data from the tide gauge at Tower Pier. As a result, the data is more accurate, but does not include rising and falling information.