One of the most frequent questions we receive is how to get weather information while out at sea. If you're looking at how exactly to get the weather, here's a blog post on how to get GRIB files to your iPhone, iPad, or Android mobile device.
But what about cost?
Getting GRIB files comes down to two main options.
WeatherNet is a subscription service that sends compressed GRIB files to your email inbox. You configure WeatherNet to send you exactly the GRIB files you're looking for, with whatever complexity you need, and you will receive them in an incredibly compressed, compact form.
WeatherNet has a vast library of weather information - far beyond basic wind and wave GRIBs. Whether you're looking for ice flow information, currents, NOAA updates, satellite imagery and more, WeatherNet has you covered.
WeatherNet is a subscription service. You then need to buy a WeatherNet data card to purchase the individual GRIB files (they get deducted from your prepaid data card until you run out of money on the card. You would then need to reload the data card, much like you reload satellite airtime minutes, for example).
At the time of writing, WeatherNet costs $99 for one year. You can buy the prepaid data cards for either $75 or $250.
There are services out there (Global Marine Networks offers a free GRIB service) that send you GRIB files, for free, over email. The service offered by GMN is done as a public service for mariners the world over and offers no tech support for any of the free GRIB files or weather data obtained through this service.
The GRIB files available for free are wind and wave files for every region on the planet. For many sailors, this is exactly the information they're needing - no need for anything more complex.
Right off the bat, those free GRIB files are looking, well, free.
And WeatherNet GRIB files are paid, on top of the subscription!
But which one really costs more?
Those free GRIB files use valuable satellite airtime to download and, more importantly, they require 2 data connections to download. One connection to send the email request to the service and another data connection to actually receive the GRIB file.
(Here is a blog post looking at satellite phone airtime billing increments and connection costs).
If we assume a typical GRIB file (typical, here, is a bit hard to pin down, since GRIB files can change dramatically depending on where you are and what kind of information you're looking for), we can say that a 3-day wind forecast for an area the size of the Caribbean is about 15kb.
Over an Iridium handheld phone it will take about a minute to download. Let's look at the difference in cost between downloading that GRIB file from the free GRIB service and from WeatherNet. In either case, we assume you're using XGate satellite email service for compression and optimization of weather files and looking at doing this over an Iridium handheld phone (for IsatPhone Pro, you can inflate these numbers as data speeds are slower, connection times longer, and billing increments more).
GRIB File With Free GRIB Service
$0.48 - Initial Connection to Send Email Request
$0.48 - 1 billing increment to send request
$0.48 - Second connection to see if GRIB has arrived
$0.48 - 1 billing increment to check if GRIB has arrived
$1.00 - Airtime to download GRIB File
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Total Iridium: $2.92
(Total IsatPhone Pro: $4.20)
GRIB File Over WeatherNet
$0.48 - Initial Connection to Send Email Request
$0.48 - 1 billing increment to send request
$0.80 - Cost of GRIB download from WeatherNet
$1.00 - Airtime to download GRIB file
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Total Iridium: $2.76
(Total IsatPhone Pro: $3.50)
Downloading GRIB files over email is very delicate work. You have to get the request exactly right for it to go through. This means that there are often added costs in the final cost, because more often that not you end up sending (and checking) if the request went through okay more than once.
WeatherNet is really easy. You draw a square over a map of the world (the area you want to get weather from) and then you check off which GRIB files you want for that area.
If the weather information you are looking for isn't available as one of the easy-to-find buttons, you can access libraries that have weather information for everywhere on the planet. We're talking GRIB files so obscure, so detailed, that it's highly unlikely that you'll find them as part of a free GRIB file download service.
So yes, WeatherNet costs money (remember you also need to factor in the $99 per year subscription fee), but just in terms of ease of use, richness of data, and integration with XGate, it beats free GRIB files by far.
In general, we say that if you are downloading basic weather once a week, or less, you'll probably save more money with a free GRIB service. If you are downloading weather more frequently, and especially if you are downloading complicated weather information like currents, you will probably save more money with WeatherNet (and have a much better user experience).
Have questions about getting weather information over satellite? Feel free to contact us and ask.