Weather to kayak

published: November 27th, 2018

Choosing the right time to go paddling is simple in your home town where you will understand the weather, but when planning a trip away and you want to be there in the best season it involves doing some research. It is pretty easy to get temperature and rainfall data for the time of year, or river levels if that’s what you need, but for coastal kayaking wind strength and direction is just as important. For kayaking, a 10 knot wind is OK but 20 knots is about the limit of what most of us can paddle against for any distance. Waves caused by a 20 knot wind can be big enough to upset a kayak.

Plan for it if you are looking for a perfect calm evening of beachside fun…

For this exercise I will use Esperance, a great little town that apart from being a place to go kayaking, is on the coast and therefore subject to sea breezes. The sun heats the planet and during the day, particularly during the hotter months, the land heats more than the sea and the hot land heats the air above it. As hot air rises colder air from over the ocean is sucked in to replace it, resulting in the sea breeze. It follows that the hotter the weather the stronger the sea breeze, and the earlier in the day it arrives the stronger it will get.

Sketch map of Esperance coast.

Sea breezes are a prominent feature of the Western Australian coastline because we have a lot of land to heat up and there are no mountains to interfere. The ‘breeze’ acts to modify prevailing winds so it is not as simple as the wind being directly onshore or offshore.

This plot of actual wind speed and direction is from www.seabreeze.com.au clearly shows a switch in wind direction after sunrise, with the weak north wind easily overcome by a cold southerly wind off the ocean.

Seabreeze is a good resource if you want to know what to expect for the next few days, but for historical data we need more.

If you are in Australia, 40 years of wind strength and direction data is presented on the BOM website as wind roses and I encourage you to visit that website for this as well as all the other invaluable information available. From http://www.bom.gov.au/index.php select ‘Climate and past data’ then ‘Weather and Climate data’ from the drop down menu on the left. Select ‘monthly statistics’ and then enter the location you are interested in. Wind roses appear as a PDF under the line, towards the bottom, ‘wind speed vs direction plot’.

…or millpond seaside conditions…

The wind rose below shows 9am wind averages for Esperance gathered and plotted by BOM from over 40 years of data.

The circles are the percentage of time and the line colour and thickness show the wind strength for the particular direction. Note that wind is described by where it is coming from, not where it is going.

The above plot shows the year average most common 9am wind is from the north, and not particularly strong. You might think that on a week’s holiday you’d certainly get some kayaking weather.

However, if you look at the 3pm Feb wind rose it tells an entirely different story.

http://www.bom.gov.au/clim_data/cdio/tables/pdf/windrose/IDCJCM0021.009789.3pmFeb.pdf

The wind is frequently above 20knots and nearly always from south or south east. This might be good for a well equipped sea kayaker to sail from Cape Le Grand to Esperance town, but for others a February afternoon of kayaking might be best avoided. And if you are planning to paddle the Cape Le Grand/Sandy Hook/Woody Island/Esperance as a multi day trip you know you are going to need a tent good for strong winds. (This trip is outlined on page 10 of the Canoe and Kayak Guide to Western Australia.)

The 9am averages, as expected due to sea breeze effect, are slightly better for off the beach kayaking in front of Esperance town, but notice that calm winds are experienced only 3% of the time. That is maybe 45mins a day. You might want to think about a different location for your beachside kayak holiday, or plan to be doing something else each afternoon. Luckily there is a very good museum in Esperance.

… because what is fun for some is risky for others.

Most of us know temperature and rain forecasts and averages, and can readily decide if to pack a raincoat or a warm coat, but understanding the information in these wind roses can take a little time. Spend some time looking at these, compare morning and afternoon, month by month and at various locations. Note that on the BOM website not all locations present wind roses and you may have to look for a nearby data point.

From knowing if it is worth loading the kayak for your next school holiday trip with the kids to planning a two week expedition, understanding what wind to expect is invaluable to a kayaker.