FAQ
Your poster
What's on a poster?
Every high and low water of 2027 for your beach or harbour, with the big spring tides picked out, sunrise and sunset, and every full and new moon. Your place is drawn like an engraved sea chart in the poster's own colours, and you choose the title, the words and the style.
Can I have my own beach?
Very likely. Search for it in design your own and we will show you its tides straight away. Most of the open coast works, often for the beach itself. If we can't make tides for a spot yet, we suggest the nearest places we can, usually a beach or harbour a mile or two away.
Can I use the poster to go sailing?
No. Our posters and calendars are not for navigation. They are for planning walks, swims, surfs and days at the beach. For navigation use official tide tables and charts, and check conditions on the day.
Your order
What sizes are there, and how much?
A3 £25 · 50 × 70 cm £45 · framed £99. A 50 × 70 cm poster can also come with a wooden hanger, or framed in oak or black (£99). Nauti-cal calendars are A3, £27. Your own words are always included, and delivery is free.
What paper do you print on?
heavyweight matte fine-art paper, printed in the UK.
How long will it take?
Each poster is made to order. We print in 2 to 4 working days, then it travels free by tracked delivery. See delivery and returns. Last orders for Christmas: Sunday 6 December (later orders are welcome, but we can't promise them for Christmas).
Do you deliver outside Great Britain?
Not yet. We deliver to Great Britain (England, Scotland and Wales) only for now, which excludes Northern Ireland, the Channel Islands and the Isle of Man.
Can I change my design after ordering?
Email us at hello@springsandneaps.co.uk as soon as you can. If it has not gone to print we will happily change it.
Can I return a poster?
Because each design is made to your choices, posters and calendars can't be returned for a change of mind. If anything arrives damaged or wrong, we will put it right. See delivery and returns.
About the tides
How accurate are the times and heights?
Close enough to plan your swims and surfs by: at most places the times are typically within a few minutes and the heights within a few centimetres. The detail is below for anyone who wants it.
We only sell tides we have tested. Our standard is that high water is within 15 minutes and heights are within 25 cm for 95% of tides, and the designer shows the expected accuracy for every place before you buy, for example "typical accuracy here: about 3 minutes and 4 cm".
To test ourselves, we took about 210 tide gauges from the Environment Agency, SEPA in Scotland and the regional coastal monitoring programmes, picked out the 95 or so we can trust, and predicted each one as if that gauge did not exist, using only the others. Then we compared the prediction with the gauge's own tide for a whole year. At the national tide gauges, 10 to 145 km from the gauges we predicted them from, the typical error was under 5 minutes and 5 cm. Next to a gauge it is a minute or two and a few centimetres.
The test also shows how quickly the error grows with distance on each stretch of coast: slowly along Cornwall, Pembrokeshire or the North East, fast in the Solent. A place on the open coast is only offered if its expected error, with a safety margin, is still inside the standard. When we checked that rule on the gauges themselves, 9 in 10 of the places it would offer really did meet the standard.
Weather moves real tides: strong wind and high or low air pressure can raise or lower the sea by 10 to 30 cm, and shift times by several minutes. No printed prediction can know the weather a year ahead, so our numbers, like official tide tables, are for the tide itself.
Why can't I have beach-level tides for my spot?
Because our tests say they wouldn't be good enough there yet. That happens in four kinds of place: far up an estuary (Truro, Wadebridge or Lymington, say), where the tide arrives late, is cut short and can leave the mud dry for hours; inside a harbour or river mouth (Padstow harbour or Salcombe), where the tide can differ from the open coast just outside, unless there is a tide gauge right there; stretches with unusual tides, such as the double high waters of the Solent and Dorset coast; and coasts a long way from any tide gauge we can test against, which includes parts of western Scotland for now. We would rather say no than print tides we can't stand behind. When we can't make tides for a spot, the designer suggests the nearest places we can, with their expected accuracy: often a beach a mile or two away on the open coast. We add gauges and re-test as we go, so try again later.
Where do the predictions come from?
From open data. The Environment Agency, SEPA and the regional coastal monitoring programmes publish the readings of tide gauges around the coast; we keep a long record of them and fit a tide model to each gauge. For a beach between gauges we use the three gauges whose tides are most like your beach's, according to the FES2022 global tide model, and work out from FES2022 how the tide changes from each of them to your beach. The slow seasonal rise and fall of the sea (about 10 cm higher in autumn and winter) comes from the gauges with several years of records. Full credits are on the credits page.
What are the heights measured from?
Posters made from one of the national tide gauges (Newlyn, Plymouth or St Mary's, for example) use chart datum, the level used on nautical charts and in tide tables. Beach posters and harbour gauges use Lowest Astronomical Tide (LAT): the lowest level the tide is predicted to reach in the 18.6-year cycle of the Moon's orbit. Either way, heights are almost always positive: a low water of 0.3 m is a very low tide. Each poster says which level it uses.
We use LAT for beaches because it can be worked out properly for any spot. Chart datum is set port by port: at UK ports it sits at, or up to about half a metre below, LAT. In our tests, carrying chart datum from the nearest gauge to a beach was out by 15 to 19 cm in a typical case, while LAT worked out for the beach matched the gauges' own to about 6 cm. So heights on a beach poster can differ from the nearest port's tide table, typically by 10 to 20 cm, while the times agree.
Will my poster show exactly the tides I previewed?
Yes. When you design a poster or calendar we fix its tides there and then: the tide model, the gauges it came from and every high and low water of the year. Your preview and the printed poster are both made from that same set, so they can't differ, and we keep it in case you ever want a reprint. We refit our tide models every week as new gauge readings come in, but that only changes designs made afterwards.
Are the times in GMT or BST?
Both, as you would read a clock: times are GMT in winter and British Summer Time from the last Sunday of March to the last Sunday of October. Each poster states the exact dates for its year, and each calendar month says which applies.
Why do some places have two high waters close together?
Parts of the Solent and Dorset coast have a double high water (or a long stand), so the "time of high water" is less sharp there. Our tests show that predicting it between gauges isn't reliable yet, so for now we only offer these places right next to a tide gauge, such as Southsea next to the Portsmouth gauge, or Weymouth from its own harbour gauge.