We have an extended discussion of how to use ASCAT wind data in our new text
Modern Marine Weather, 3rd ed.

With internet connections you can obtain these data in graphic format direct from

Royal Netherlands Meteorological Institute (KNMI)


Ocean Surface Winds Team (OSWT).

Available online




A and B
12.5-km ASCAT*


A and B
25-km ASCAT
A and B
25-km ASCAT**
A and B
50-km ASCAT
25-km WindSAT ***
25-km WindSAT

* This 12.5-km coastal data is enhanced for more detail near shore than is usual in satellite winds.

** The source marked in yellow is the day to day working source for many applications, primarily because of the very convenient file naming structure used by OSWT.

*** WindSAT is a US Navy product, independent of ASCAT

Other ASCAT related resources

ASCAT Manual from EUMET

Video: Introduction to ASCAT

How to get ASCAT graphic data via Saildocs

Predicting the times of ASCAT (Metop) passes

How to make an auto-updating overlay of ASCAT data in Google Earth.

Get ASCAT data in GRIB format directly from NCEP

These GRIB data can also be downloaded directly from within the few programs that are capable of viewing the data... as of Aug, 2018 we know of these:

LuckGrib (Mac or iOS) video: ASCAT in LuckGrib

Ocens (PC or iOS)  video: ASCAT in Ocens GribExplorer

Expedition (PC)    video: ASCAT in Expedition

(The above commercial products are the most convenient way to obtain and view ASCAT data in GRIB format, but the GRIB data can be viewed in the public program Panoply, but it takes a bit of patience, as shown in this video.)

Ascending pass above; descending pass below. (Satellite tracks curve west as the earth rotates to the east below the polar orbit.)

The valid universal times (UTC, same as GMT) of these maps are listed in small purple numbers at the bottom of the figures. These samples are from a set of passes that span the time period T1 to T2, where T2 = 0414 Sept. 26, 2012, and T1 is 22 hr earlier, which would be T1 = 0614 Sept. 25, 2012. The pass times for these samples (0704, 0845 and 1931, 2111) would therefore all be for Sept. 25.

The 22-hr data sets are updated every hour, so the 2111 pass is the most recent, being (0414 Sept. 26 - 2111 Sept. 25) about 7h 03m old.

Be aware of the file sizes when downloading the wind maps by satellite phone.

Please check out our free email service we offer for email delivery of near-live ship reports in your vicinity ( Ship reports and ASCAT are the truth meters we need to evaluate all forecasts.