Cool Seaplane Pilot Weather Tools

If you could stand on the east coast of the eastern most island in the Philippines and face the Pacific Ocean you would feel the warm moist trade winds blowing gently on your face. On a computer generated wind map the wind lines meander westward across the ocean, like millions of wildebeest migrating across the Serengeti, where they funnel into a natural barricade – the Philippine Islands.

Pacific Trade Winds-03

These are the north easterly trade winds that would, unaffected by any land mass or pressure systems, flow westward all year round. These winds are, however, affected by either the summer season heating of the Asiatic landmass or the winter season cooling of the China/Siberia landmass. During what Filipinos call the “Habagat” the trade winds are affected by the South West monsoon and associated warm moist air and during the “Amihan” the trade winds are affected by the North East monsoon and associated cool dry air. This really gets mixed up when either are affected by typhoons which develop from extreme low pressure systems associated with the warm moist air along the Intertropical Convergence Zone. Although Typhoons can happen in either season the typhoon season generally corresponds with the Habagat monsoon. Most typhoons, like bowling balls rolling down the ICZ bowling lane, move in the same direction as the Amihan monsoon from east to west. Confusing? In reality the seasonal changes are much simpler to understand and there are a number of apps that help out.

On Oct 24th somewhere between 4 pm and 5 pm the winds in Boracay switched from South West to North East. During the recent typhoon the winds had switched across the island several times but this time the locals knew it was here to stay. Following an ancient ritual that most likely started with local fishermen, the paragliding boats, bubble helmet dive rafts, dive bancas and sail boats moved to the protected lee-wind western side of the island while the kite surfers, mostly counter culture trustafarians, moved to the eastern side of the island to catch the onshore breezes. If you had been there the day before you would think the north and south poles had reversed.


It took another 3 days for the winds to pick up momentum to where we could recognize the brisk signature North East trade winds. The Amihan monsoon had arrived. How did they know to all at once and all in one day make the seasonal move? I am sure they all felt it in their bones but at the same time the switch was perfectly predicted on an app.


When my father flew in Northern Canada during the 1950’s they were lucky to have some of the world’s best navigational maps for their day. But these were often dead wrong like finding two rivers where the map says there was one. Weather reports, if they were able to get any, were wholly unreliable. Bush pilots learned to read the sky: Mare’s Tails, Sun Dogs, Mackerel Skies and Red Sky at Night, in conjunction with a barometer, told you more about what was coming than any government issued weather reports.

Sun Dogs in Manitoba

Sun Dogs in Manitoba

As seaplane pilots who’s flights often take us far from airports or flight service stations I believe we still need to be able to interpret the changing weather around us. I am from the old school so I learned to do all that but what about the new recruits raised on smart phones and apps? Luckily cell phone coverage is expanding rapidly so getting weather updates is easier. But with a busy schedule and while handling the seaplane on swells in open waters and on beaches with surging rollers we don’t often have time to check our smart phones. It’s quicker to look toward the sky, read the winds and check the trending barometer.

If you have to ask “How do you get the barometric pressure reading when you are out of touch of the airport?” then you are not a sailor or seaplane pilot. You simply set your altimeter to sea level before each takeoff and check to see which way the pressure is trending.

In Europe and North America the weather apps are amazing and concise showing weather conditions on moving maps direct from Doppler radar. Weather in real time. But I will show you what android apps we are using in the Philippines and what is available in many other counties.

NOAA  or National Oceanic and Atmospheric Administration is the good old USofA government helping us all out around the world. The best free app that gives NOAA weather and tides that I can find is Weather from NOAA free.  For an overview go to Satellites Color – Western Pacific. I don’t really use this one a lot but it is useful when typhoon watching.

Not to be confused with NOAA the Philippines government operates Project NOAH (Nationwide Operational Assessment of Hazards) which was set up to serve timely warnings about typhoons, tsunamis, earthquakes, flash floods and volcanic eruptions. For pilots NOAH is best for showing live views of areas of heavy rain and ongoing storms throughout most of the country using the Doppler radar stations in Aparri, Subic, Manila, Virac, and Cebu. When you can’t see over the horizon this is the next best thing.

Project NOAH

A great app more specific to seaplane pilots is one that shows and predicts the tides. My favorite is DGS Tides. which is only available as an android app. The best part is that it runs completely off-line and helps find the closest station using your devices GPS. It is simple to use and accurate.

dgstides_graph dgstides_map

Even more amazing is the apps that show and predict surface winds, waves and swell heights and direction. I have three that I use that are available either on your PC or through an android app. Windyty is hands down my favorite not just because it has so much to offer;

Windyty Wind

But because it shows the wind in a way that transcends science to become living art. Wind and or waves in action are fractal non-repetitive patterns at their most beautiful like large flocks of starlings soaring in flight or balls of herring darting in unison in the sea.

Windyty Map

A great feature is the ability to click on the exact spot you wish to see the actual wind and waves predictions and the ability to forecast for weeks in advance. I can predict if I have to land on the NW or SE side of Boracay Island simply by clicking on the Windyty map and selecting my date and time of arrival.

The PC version of Windyty is authentic but the app is offered by a third party. The app version is called Windity – No Oficial for the obvious reasons I doubt if it is sanctioned by the original author. But it still works if you can find it.  If you don’t want to use the app, however, the site works well in your smart phone browser.

A more official wind and wave projection app for kite surfers is called Wind Finder. It works fine but it does not give me the swells and I have to manually search for the locations I want to check out. That does not work if the name for the area I have is different for the name that their data base uses. Also I find the wind maps too crude and generic. The wind maps for Windyty are exact enough to be used without the text predictions. What you see is what you get.


Another web site that gives a very accurately depicted wind maps is called Westpacwx. Again I love the graphical depiction of the wind on this site. It is poetry in motion.


There is no android app for this PC version but then I mostly use the wind prediction sites for just that; predicting what the wind will be like the next afternoon or the next week. I can do this from home of the office. You can also click on the map to get specific details for each location which is a great feature.

Using the wind, wave and swell prediction abilities is a learning curve. You could not just look it up and know what the conditions will be like at each seaplane landing location. Wind, waves and swells are also affected by the local conditions; lee wind effect from mountains and large islands such as Mindoro Island has on the waters around Apo reef, the venturi effect on the wind between two islands such as between Luzon and Mindoro have on Puerto Galera or wind changes from localized thunderstorms in northern Palawan.

The Manila Harbour, for another example, is a wind tunnel. When the apps show the SW wind blowing from the ocean into the harbour at 8 kts you should know it will be 16 kts at the deepest end of the harbour. The harbour mouth creates a natural venturi effect and in the afternoon the heating over the city and the hills behind the city will create an anabatic inflow speeding up the natural occurring trade winds. This is a very local effect that the apps cannot predict but you, as a seaplane pilot, need to know. Any wind over 8 kts on a long fetch can create large difficult waves but 15 kt winds can create swells up to 2 meters high. Not safe for landing at any speed.

Throw in a typhoon and 18 kts and stronger winds can produce 3 meters swells that will break over the Manila seawall. At this point the harbour is not a safe harbour.

Manila South Harbour-55

Manila South Harbour during the SW monsoon.

Now that the winds have changed to the North East during the Amihan Monsoon we rarely get waves larger than 1-2 feet allowing us to once again operate safely into the Manila South Harbour.  Welcome home.

C208B EX Amphibian Seaplane

C208B EX Amphibian Seaplane

C208B EX Amphibian Seaplane landing in the Manila South Harbour Philippines.

About John S Goulet

Air Transport Pilot, consultant, writer, blogger and photographer with 45 years in Professional Aviation.
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