Catching the lowest low and highest high for coastal photography
Coastal photography lives or dies on light and water level. The light part is golden hour, sunrise and sunset, and you don't need a tide chart to plan that — a sun calendar is enough. The water-level part is where the tide chart becomes essential. The same headland looks like three different headlands at low water, mid-tide, and high water. Some shots only exist for two hours a month, when the lowest of the spring lows happens to fall at sunrise or sunset. Tide planning, for a photographer, is half the work of finding interesting frames in places that have already been photographed by everyone for the last fifty years.
Low-tide shots are about exposure
When the tide pulls back to its monthly minimum, you get foreground: wet sand, kelp lines, exposed rocks, tide pools full of reflected sky, sand patterns the receding water left behind. None of this is visible at average tides. The tidal coefficient on a given day tells you in advance whether the low will be deep enough to expose the things you want — coefficients above 90 are spring tides, coefficients below 50 are neaps, and you'll see almost nothing at low water on a coefficient-30 day. Plan around the coefficient first, then around sunrise.
High-tide shots are about scale
At the top of a spring tide, the ocean comes up to walls and steps and points it doesn't reach the rest of the cycle. Stormy high spring tides look apocalyptic for the same reason — water is at its absolute upper limit on the geometry of the coast. For long-exposure landscape work, a calm-day high spring at sunrise can give you reflective sheets where there's normally rock. Check the predicted height alongside the time: a high spring at 18:30 in summer at a west-facing coast is one of the better photographic windows of the year, and they're rare enough to plan for months in advance.
Why harmonic prediction is the right tool
The tide tables on this site come from harmonic prediction at a real gauge for the place. That means you can plan a shoot for a date six months away with confidence — within a few minutes for the time, within a few centimetres for the height, under normal weather. Storm surge during a low pressure system can shift the actual water levels above prediction by 20 to 30 centimetres or more, which on a calm photographic day rarely matters but on a heavy-weather one absolutely does. The prediction is the astronomical baseline. The weather is the variable on top of it.
The narrow window of overlap
The single most photogenic moment on most coastlines is when a spring low at the bottom of the lunar cycle lands on top of a sunrise or sunset that's also at the seasonal optimum. In northern temperate latitudes, that means September and March equinox windows at sunrise are when you catch the longest sequence of low-tide-plus-golden-hour days in a year. In southern temperate, March and September flip. Tropical coasts are flatter — the ranges are smaller and the overlap less dramatic — but the same principle holds. Look at the seven-day table for the place you want to shoot, find lows under 0.3 metres above MLLW falling within 90 minutes of sun rise or set, and book accordingly.
What changes between visits
If you photograph a coastline over a few years, the rocks and the cliffs are still there but the sand and the kelp move. After a winter of storms, beaches get scoured down to bedrock that hasn't seen daylight in decades. After a calm summer, sand piles back in and covers shapes that were sharp the year before. The tide didn't change — the substrate did. Knowing that, the same low-tide spring window can look completely different on two visits five years apart. Bring a camera each time anyway. Frames you shot before are gone, and frames you didn't see last time are usually waiting.