The XyGrib FTP and Email Service for Linux, MacOS and Windows


This page was written for zyGrib which is no longer supported although it will continue to function. An improved service is XyGrib, a fork of zyGrib. XyGrib will be updated from time to time. It will be expanded to be able to decode other GRIB formats. Much of what is written here will apply to XyGrib.

What this page is about

ZyGrib is an excellent GRIB service with an easy-to-use email facility


ZyGrib is freeware developed initially for Linux/Ubuntu users but also available for Windows. It is available under General Public Licence.

Latest versions of the software and versions for Linux, MacOS or Windows can be downloaded from the zyGrib site. The Windows version is zipped

An unzipped Windows version of the software can be downloaded from The Dutch Zilt magazine site. This is a "heavy" download and will not be the latest version.

The download will probably be in Dutch but, using Options (Instellingen) - Language (Taal), there is a choice of English, French, German, Spanish, Italian and Greek. The data are compressed so that file sizes are even smaller than Saildocs.

Those with enquiring - and technical - minds might like to see the ZyGrib description page.

Setting up and using

This is all very intuitive. Areas can be selected by drag and drop or entry into a frame. Map projections can be chosen as well as amount of detail such as rivers, coastline definition, cities, latitude/longitude grid, scale.

zyGrib request panel

The examples shown here are all using zyGrib Ver 6.0.2. At 2 February, 2017, we are up to Ver 7.90.

zyGrib selection panel

Weather elements required, number of days and time step are all entered into a frame as shown below. The selected area can also be amended here. By default, it will use your last selection.

zyGrib forecast from this request

zyGrib forecast

Step on times using the Left/Right arrows - top left of the chart or by using Page Up or Down.

Using zyGrib V7.0 or later, Data can be requested on a 0.25 degree grid or larger. Number of says can be up to 10.


A useful facility with zyGrib is the option to download the CAPE (Convective Available Potential Energy). This frighteningly named parameter is an indicator of strong convection and, therefore, the risk of severe thunderstorms and lightning.

This example shows the Mediterranean with high values, in red, showing great instability. this is a clear warning of vigorous convection and a high thunderstorm and lightning risk.

zyGribCAPEUK  forecast

This is an example in UK home waters. The yellow colours indicate a risk of thunderstorms and lightning but not very great. This is the same weather situation shown above. The much lower risk is a consequence of the lower sea temperatures and lower instability.

Weather sequences (meteograms)

This is a useful facility. Select a point on a zyGrib display by right-clicking. Select Meteotable from the small window that opens.

zyGrib sequence

Installation problems?

Windows users may have experienced problems when unpacking compressed versions of the software but these have now been resolved .

zyGrib by email

To set this up -

  • First register as a zyGrib forum user.
  • Go to the zyGrib email page, enter your zyGrib userbame and password. This generates a user code that is valid for two months.
  • Requests go to with subject gribauto
  • The request syntax is as follows. All the Left hand column bold font text must appear except when not needed.

login: Username

code: user code

area: 45N2W 47N0E

(For example)

resol: 0.5

(or 1 or 2)

days: 5

(Up to 8)

hours: 3

(Multiple of 3)

waves: WW3-MEDIT

(Can be deleted)


(or Skiron Mediterranean meso-scale


(Delete elements not required)_

NOTE: A user code will last for two months but you can renew whenever required.

It may look complicated but is, in fact, easy to use. Simply copy and paste the text in bold font into an email, change numbers and select elements as required.

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