Tide prediction software

Getting the tide right is important for some kinds of diving. At seamounts and other exposed sites, there may only be a narrow window when the dive can be safely attempted. Lagoons and extrances to oceanic atolls can be great dives with lots of fish action on an incoming tide, but a milky mess on the ebb. The timing of some great marine wildilife behavior (such as spawning) is closely linked to tides as well. I've long been looking for a good tide prediction program with a database broad enough to cover some of the sites I dive here in southeast Asia. Now I've found it.

For me, there are four stations around Bali (one at Benoa, near where I live, another at Buleleng in North Bali (not far from Tulamben), two more in the straits between Java and northwest Bali (near Menjangan Island), and two more on western Lombok, making it possible to combine with the Benoa data to get reasonable times for Nusa Penida. For Komodo, there is no station in the park itself or at Labuanbajo, but there is a station on southwest Flores near the southeast corner of the park and another in Sape Bay on Sumbawa opposite the western side of the park (and another for Bima), again making it possible to at least roughly interpolate tides at Komodo sites. There are also tide stations for Kupang, Ende, two in south Sulawesi, Alor, and wonder of wonders, even one site at Saonek for Raja Empat. Quite a few stations for PNG and the Solomons too. For North America, of coure, the coverage is much better.

WXTide32, a free (Windows) program by Mike Hopper, is based on XTide, a UNIX program written by Dave Flater. The program is very easy to install and use. It covers more than 9,500 tide stations worldwide, and can present tidal data in a variety of formats. For North America, there are also 100+ tidal current stations (don't ask me how this part of the program works - I don't know.) The current version of WXTide (4.2) was released in July, supports World Vector Shoreline (WVS) map files, which must be downloaded and installed separately. These are different from the NOAA WVS files, but are also free. The full set of WVS map data files provide zoom factors from 1:43,000,000 to better than 1:250,000, which means you may be able to zoom right in to your favorite dive site.

Few things in life that are really good are free, but this is. (Needless to say, I have no relationship with the author of this program - I'm just delighted to find it.

WXTide32

Note: There is a also a very decent tide prediction program for the Palm Pilot. I use this to time my walks on the beach at the lagoon with my dog. Though it doesn't have quite the database that WXTide does, it may be possible to insert new stations with time offsets and correction factors derived from the WXTide32 database.

Tide Tool for Palms

Enjoy

Frogfish (Robert Delfs)

Very nice program, too shame its doesn't have stations location in the Red Sea where most of my dives are.

btw: you have an error in the link, remove the duplicate http part.

Arnon,

Thanks for the correction on URLs, and I'm sorry the program's database doesn't cover the Red Sea sites you need. I didn't attempted to evaluate the coverage worldwide, just checked for the places I need.

You might want to keep an eye on the program. When the International Hydrographic Office (IHO) disbanded in 1999, ownership of tidal data reverted to individual countries and the blanket approval for non-commercial use previously extended for the UK, Ireland and Scotland was withdrawn, so the predecessor version to the program had no coverage in UK, Ireland or Scotland between 2001-2004. The UK Hydrographic Office wanted the developer to purchase a license, something which he understandably was not willing to do, since the program is distributed free of charge. The current version has data from a different source with 44 stations in UK waters, but that is much less coverage than was available before.

It could be coverage for the Red Sea will be added (or restored) in the future. It's also possible that some stations now covered will not be available in future versions of the program, if other countries follow the example of the UK and eliminate free non-commercial use.

Check also the links page on the WXTide32 site - there are some other programs (some commercial) that may offer the coverage you need, and there are also sites which purportedly will help you design your own tide tables.

As a UK taxpayer I am understandably irritated about the protectionism shown by the Admiralty over issues like this. Considering the safety implications its about time they were brought to heel and made to surrender such info to none profit making or similar organisations! That said, they can be very helpful and do produce extremely good charts!

Hi Paul,

Have you tried EasyTide online ? It'll give you free world-wide tidal linformation for up to 7 days.

JP

7 days is all very well, but I'd rather like to know what the tides are doing next year when I'm at the other end of the country. This info doesn't seem so easy to come by!

As a Dutch taxpayer, I am verry fortunate with our Rijkswaterstaat (Ministry of Transport, Public Works and Water Management). They have a site where I can find the tides all over Holland for the upcomming years verry detailed.

You can even export the graphs and tables to Excel or other programs, intergrate the data with your electronic agenda.

http://www.getij.nl/index.cfm (english)

I have been using an old DOS based programme called "ShowTide" for the past 20 years or so. It is suitable for anywhere in the world as long as you have the tidal harmonic for the location that you are intersted in.

The software was written by Dr John Amson, of Fife in Scotland , and even though it is a DOS programme I find that it still works with Windows XP. It has a graphic display for any 3 days and will show the tides in "real time" if you, so wish, or will even prepare a tide table for any month or year that you are interested in, provided that you have the tidal harmonics for that particular location.

It also will work out the highest and lowest tides during any period that you choose, future or past.

It also gives the rising and setting times for the moon and sun.

Tidal harmonics can be purchased from various sources in printed form, or possibly via the Internet, maybe free. This latter source though, I'm not so sure about.

Technically, from a computer aspect, it is not very "up to date" being a DOS programme, BUT............. as it has so much to offer, I am still prepared to continue to put up with it's short commings.

I have tried other programmes that are around, but none, in my eyes, come up to the standard of this "old fashioned" software.

The programme was NOT FREE when I obtained it many years ago, but Dr Amson was kept intouch with me and sent me many changes and improvements over the years.

If anyone is interested I can give you his e-mail address. I have no commercial interests in this programme