Pacific Area S/V Hoku Pa'a

Weather Charts and Weather Fax

We use weather information en-route to help fine-tune our course.  Generally we want to avoid areas of excessively high or low winds, developing storms, or direct head winds. Even though at 6 knots (about 11 km/h) we can't outrun bad weather when it's chasing us, we can head to where it might be less nasty.

We receive this weather information via HF shortwave radio. There are voice broadcasts, such as station WWVH (from Hawaii on 5, 10, 15, 20 MHz at 48 minutes past each hour), and there are weather maps. Weather maps (also called weather faxes) are transmitted by coast stations such as KVM (Hawaii), and we receive them by tuning the shortwave receiver to the right frequency at the start time, and attach the headphone output to our laptop's microphone input. Software on the laptop ( decodes the fax data and shows us the picture. It takes a lot longer to download than a regular fax, about 20 minutes, and depending on the radio reception the quality can be quite variable, but they are handy.

A second way of receiving weather faxes is via email. A satellite phone or HF radio modem (which we have) connects to an email provider on shore, which sends the weather fax as an attachment. The email option has the advantage of being faster, but more expensive.

A typical weather fax can be seen here. Some resolution in the original file has been lost while making it a reasonable size for the web site (the original is more than 300kB) but you get the idea.

If you are interested in this topic, the symbols on the weather fax and the various available products are explained at   This website also posts the same weather faxes that we receive over the radio.  You can also go to as another source of weather information.

Address S/V Hoku Pa'a
1000 DeCosta Pl.
Victoria, BC
Canada  V9A 6Y3
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This page last updated 7 Jun 2020