Yasuda Rivermouth Surf Forecast and Surf Report

G’day, Rusty here. Lookin’ at the 16-day surf picture for Yasuda Rivermouth, and I gotta be straight with you right off the bat—this is a tricky stretch. The spot is a reef and river setup that rarely breaks, so it’s not a place you can just rock up and expect waves. We’ve got a long gap of weak, messy surf for the first week and a half, with a few better windows later on, but they come with their own warnings. The water temp is sitting at 85°F, which is about a touch warmer than what’s normal for this time of year, so you’ll be fine in boardshorts.

For the first several days, from Wednesday 26th August right through to Monday 31st August, the swell is small and weak. Swell heights hover around 3ft to 6ft, but with periods mostly short—7 to 12 seconds—and combined energy readings are low to moderate (between 113 and 1248). The wind is mostly onshore, so the waves are gonna be crumbly and messy. The 26th has a 6ft swell from the SSW, but with marginal conditions and a low score, it’s not worth paddling out. Nothing really stands out here; it’s a flat spell.

Then we hit a couple of days—Tuesday 1st and Wednesday 2nd September—where the swell jumps up. On Tuesday morning, we’re looking at 8ft from the SSE (12 seconds), and by the afternoon it’s 10ft from the same direction. Wednesday morning pushes to 12ft SSE, then 13ft in the afternoon. But here’s the catch: the wind is cross-offshore on Tuesday (clean for the experienced), but by Wednesday it turns into a strong cross-shore with messy cross-chop, and the combined energy readings are huge (4117 to 5575). The swell is way too big for beginners—over 8ft—and with the short period (10–11 seconds), it’s gonna be a washing machine. This is expert-only stuff, and the quality is poor. I’d say this is more interesting for kite surfing than paddle surfing, especially on Wednesday.

Thursday 3rd and Friday 4th September stay big but messy. Swell heights are 10ft to 12ft, but the wind is cross-onshore, making it choppy and rough. Energy readings are still high (2366 to 3908), but the conditions are poor to marginal. Not a good look.

Saturday 5th September sees the swell drop back to 7ft in the morning and 5ft in the afternoon, but the wind is cross-shore, and the period is short (8–9 seconds). The afternoon is particularly poor. Sunday 6th is similar, with 5ft and onshore wind.

Now, the standout period comes on Monday 7th and Tuesday 8th September. Monday morning is glassy—zero wind—with a 7ft swell from the SSE (10 seconds). The combined energy is 819, which is moderate, and the conditions are described as “glassy.” This is a proper window for clean waves, but the period is moderate, so the breaks might be a bit soft. The morning is the best bet. Then Tuesday 8th morning is glassy again, with a 10ft swell from the SE (11 seconds), and energy jumps to 2213. This is excellent for experienced surfers, but at 10ft, it’s too big for beginners. The long period (11 seconds) means it’ll have some punch, but being a river/reef, it might hold up better than a beach break.

Wednesday 9th September morning is also glassy, with a 8ft swell from the SSW (12 seconds) and energy at 2019. That’s another good one for experienced crew. Thursday 10th September morning has a massive 12ft swell from the S (15 seconds) with energy at 5586, but the wind is onshore, so it’s not clean. That’s a powerful, very long-period groundswell, but you’ll be fighting the wind.

Overall, the best on offer is the glassy mornings of Monday 7th and Tuesday 8th September. Monday is more manageable size-wise (7ft) and clean, while Tuesday is bigger but still clean. For experienced surfers only on Tuesday. The rest of the period is either too small, too messy, or too big with bad wind. With this spot rarely breaking, a blank run isn’t unusual, but we’ve got a couple of windows to keep an eye on.

Rusty, signing off.

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