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Pointers to GRIB viewers to help you choose. However, it is largely a matter of personal likes and dislikes.

Viewers for GRIB files

WMO (World Meteorological Organisation) developed GRIB code as a means to store and exchange computer output in a compressed form. This was so that they could then be displayed on any chart whatever the scale or projection.

Those providing GRIB data to sailors have developed many viewers. Some are free, some are charged for. Some are intended for use with a particular commercial service. Others will wors with GRIB data from any source.

These are a few that I have used. Their principal merits are simplicity and ease of use. I have looked at viewers supplied “free” by various commercial firms but have found them over complicated.

Remember that whatever viewer you use, the data all come from numerical weather models. For sailing purpose, particularly cruising, the US GFS will not be bettered overall. Unless you want to pay for a service that can be obtain at no cost, then these viewers, especially the first two will meet your needs.

GRIB files usually have the extension .grb, Some are compressed further and have extensions .grb.bz2.




The first GRIB viewer developed by SailDocs for users of SailMail, the user funded HF radio service. There have been few changes; it is basic, easy to use with crude topography and no frills. For details, send a blank email to info@saildocs.com.



My preferred viewer. PC, MacOS and Linux versions Many data options. Choose the presentation to meet your needs. Intended for use with the free zyGrib but will read both .grb and .grb.bz2 from other sources. Software from zyGrib or a rather large download from the Dutch magazine Zilt.



An easy to use viewer from Theyr.com for PC. Mac OS and Linux also available. Only works with .grb and NOT ,grb,bz2.



The MaxSea viewer is another simple viewer with few frills. There are problems in getting a key. Start from Zilt, the Dutch Online Magazine Site and be careful to follow the instructions in their guide.

Other viewers are available to buy but I see no reason to do so. Most viewers have the facility to let you read the actual forecast speed. That helps distinguish between a 15 knot wind vector which could be anything between 12.5 and 17.5 knots. Most will let you step on one chart at a time or give you a movie. Most will let you look at the weather at one location.

The various chart-plotters have their tailor made versions which will be similar to those that I have listed above.

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