So here it is: 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.
In their way [the docks] are as romantic as the river they serve is unlike all the other commercial streams of the world. The cosiness of the St. Katherine’s Dock, the old-world air of the London Docks, remain impressed upon the memory. The docks down the river, abreast of Woolwich, are imposing by their proportions and the vast scale of the ugliness that forms their surroundings—ugliness so picturesque as to become a delight to the eye. When one talks of the Thames docks, “beauty” is a vain word, but romance has lived too long upon this river not to have thrown a mantle of glamour upon its banks.
—Joseph Conrad, The Mirror of the Sea
Massive thanks to Tom Taylor for above-and-beyond technical assistance, particularly with fiendish Tide-related trigonometric functions, and to Tom Armitage for poking me in the right design direction.
P.S. If the domain is a bit of a mouthful, thamestide.com will also work, for now.