Average period of surf, but there'll be waves

Ben Matson picture
Ben Matson (thermalben)

Sydney Hunter Illawarra Surf Forecast by Ben Matson (issued Friday 17th Dec)

Forecast Summary (tl;dr)

  • Freshening NE winds and deteriorating conditions on Sat; chance for a brief window of light winds early and easing SE swells from today
  • Solid NE swell on Sunday but generally window affected (chance for a brief window of light winds early)
  • Easing NE swell Mon with S'ly winds developing
  • Small flukey S'ly swells Tues/Wed, looking a little better/bigger Thurs/Fri
  • Couple of interesting options for the long term/Xmas period


Two south-east swells have provided OK waves over the last few days, with peaky 2ft surf early Thursday building to 2-3ft in the afternoon, and reaching 3ft+ today with the arrival the second swell. Thursday was bumpy under a moderate S’ly breeze that freshened through the day but this morning offered clean conditions with light morning offshores ahead of afternoon NE sea breezes. The only exception was the Hunter which saw persistent S/SE winds this morning in the wake of yesterday’s airstream.

This weekend (Dec 18 - 19)

Freshening N/NE winds will deteriorate surface conditions through Saturday. There’s a chance for early light N/NW winds in a few spots but it won’t last long. 

Today’s SE swell will be easing in size, so aim for exposed northern ends where you may see some leftover 2ft+ sets. The NE windswell should build to 2-3ft by the end of the day but quality won’t be high.

The models have stalled and weakened a small trough that was expected to encroach the region into Sunday morning. Some locations could see a short-lived window of light variable winds around dawn, however the N/NE breeze is expected to rapidly restrengthen through the morning and it’ll become gusty into the afternoon. 

The good news is that this will build surf size a little higher, with 3-4ft sets at exposed beaches through the day (perhaps a little undersized early). Look for some protection inside a northern corner if you can, and keep your expectations low.

Next week (Dec 20 onwards)

A more dominant trough will push into Southern NSW early Monday, with a chance for early light winds - mainly north from Sydney - ahead of a gusty southerly change. With Sunday’s northerlies expected to persist for much of the night, the NE windswell should maintain size early Monday morning with 3ft, perhaps 3-4ft sets at NE facing swell magnets however it’ll trend steadily down through the day, to 2-3ft by lunchtime and perhaps a little smaller by late in the day. 

We’ll see a concurrent increase in small local S’ly windswell too, though without any major size (2ft+ south facing beaches by lunchtime).In fact, most of the south swell we see on Monday will be mid-range energy from W/SW gales exiting eastern Bass Strait overnight Sunday. 

The rest of the week looks active, but generally on the periphery of our swell windows. 

A vigorous frontal passage south of Tasmania from Sunday through Wednesday will generally be poorly aimed within our swell window, so wave heights will be very small from this region through Tuesday and Wednesday - perhaps some 1-2ft sets at south facing beaches, with rare 2-3ft sets at reliable south swell magnets like the Hunter. 

The tail end of this progression should slingshot a final front through a better sector of our south swell window (late Wednesday) and this is expected to set up a better pulse of south swell around Thursday and Friday. We’ll have more confidence on that in Monday’s update.

Elsewhere, and a tropical low east of Vanuatu this weekend is expected to slip south and should start to enter our swell window around Monday. By this time, it may show a small, but reasonably well aimed E/NE fetch within our far NE swell window. The short fetch length concerns me, but the latest model guidance does show a good pathway (to the SW) so I’ll be keeping a close eye on this for NE swell potential mid-next week. Probably won’t be much though, unless we see a major upgrade and some useful high pressure building to the south, to help draw out the fetch length.

Lastly, lingering troughiness across the western Tasman Sea mid-late next week looks to be one of several favourable ingredients (a few others not yet showing) for swell potential leading into Xmas Eve, Xmas Day and Boxing Day. And there may be a cyclone brewing in and around the Coral Sea later next week too. 

It’s still early days, but I’d quietly pencil in the possibility for some festive surfing opportunties around this time, despite the models not really being on board just yet.

See you Monday!


Craig's picture
Craig's picture
Craig Sunday, 19 Dec 2021 at 5:31pm

Hectic storm this afternoon on the beaches. I was out surfing in it and while windy, it was a fairly normal blow, then abate as it passed. Unfortunately it looks like there was a tornado up through Dee Why and Narrabeen that's caused loss of life and property. Thoughts to those who've been caught up in it :(

Montygoesbananas's picture
Montygoesbananas's picture
Montygoesbananas Sunday, 19 Dec 2021 at 7:59pm

Was caught out in the water at north curly, pretty hectic there for about 10 mins the glass off after was amazing after full horizontal rain and swell moments earlier. Very sad about the fatality sounds like one of the trees at narrabeen was hit by lightning and came down.