Surf Forecasts:
Cat Bay (Shelly Beach) surf forecast from 29 Jul 2026:
- Best quality surf: Friday 31 Jul, 4AM (local time) - 5ft (1.6m), 12s period, SW swell with cross-offshore winds.
- Most powerful swell: Wednesday 29 Jul, 4PM (local time) - 13ft (4.0m), 16s period, SW swell with 7,127 kJ wave energy.
- Next surfable swell (1★+): Friday 31 Jul, 4AM (local time) - 5ft (1.6m), 12s period with SW swell.
Best Forecast Surf Conditions for Cat Bay (Shelly Beach) this week:
The surf forecast for Cat Bay (Shelly Beach) over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Friday (Jul 31) at 4AM. The primary swell is predicted to be 1.6m and 12s period with a secondary swell of 0.1m and 23s. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Cat Bay (Shelly Beach) in the next 16 days are 4.0m 16s and forecast to arrive on Wednesday (Jul 29) at 4PM. Winds are predicted to be cross-offshore at the time the swell arrives.
| Wave Type | Time (AEST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 4AM (Fri 31st Jul) | 5ft (1.6m) 12s |
| Best Surf | 4AM (Fri 31st Jul) | 5ft (1.6m) 12s |
| Most Powerful | 4PM (Wed 29th Jul) | 13ft (4.0m) 16s |
Table - best surf conditions forecast for Cat Bay (Shelly Beach) over the next 16 days.
The Lowdown
Alright, Rusty here again. Let’s break it down in feet and miles per hour.
It’s pretty bleak for a while down at Cat Bay. We’ve got a massive, powerful SW groundswell pushing in, but the wind is just brutal. From Wednesday the 29th right through the end of July, it’s strong cross-offshore winds tearing up any chance of a decent wave. The energy is huge, with the combined swell energy hitting a massive 10,886 on Wednesday morning, but it’s all wind-chop. Thursday and Friday the swell drops to around 4.6ft from the SW, but the wind is still onshore or cross. Even that glassy Sunday morning on the 4th of August with 7.2ft SW swell is ruined by a fresh cross-shore breeze. Honestly, the first eight days are a write-off for paddle surfing. If you’re into kiting, those strong winds and 6ft+ swell from the 3rd to the 5th might look good, but for us, it’s a no.
Then, the 6th of August. Thursday afternoon. That’s the one. It’s not huge, but it’s clean, with a 4.9ft SW swell, a 15-second period, and the wind goes glassy. The energy is moderate (990) and it’s the first time everything lines up. The water temp is around 56.3°, which is about average for the year at Cat Bay (Shelly Beach). This is your best bet for a peaceful, clean session. The crowd can be often here, but on a Thursday with conditions like this, you might snag it.
Friday the 7th of August afternoon is another beauty. Glassy again, with a 4.6ft SW swell and a very long 15-second period. That kind of long period groundswell from the SW is perfect for a sheltered spot like this, giving you long, clean lines. The energy is 1,053 (moderate). This is the standout for the whole forecast. Don’t miss it.
After that, the weekend of the 8th and 9th gets messy with onshore wind and building swell up to 11.5ft, which is expert territory. Then, the following week looks wild. The 11th of August shows a 14.8ft WSW swell with a 20-second period and a colossal energy of 26,109, but with strong cross-shore winds. The 12th also has a 18ft monster with a 16-second period, but again, messy. Too big and too windy. So, your two windows are the 6th and the 7th of August. Get in there.
Short Range ForecastLight rain (total 9mm), mostly falling on Wed morning. Very mild (max 12°C on Wed morning, min 10°C on Fri night). Winds decreasing (strong winds from the SW on Wed morning, calm by Thu night). | Days 4-6 Weather SummaryLight rain (total 5mm), mostly falling on Mon afternoon. Very mild (max 14°C on Sat afternoon, min 9°C on Sat morning). Winds increasing (light winds from the N on Sat morning, strong winds from the WSW by Mon afternoon). | ||||||||||||||||||||
Wednesday 29 | Thursday 30 | Friday 31 | Saturday 1 | Sunday 2 | Monday 3 | Tuesday 4 | |||||||||||||||
AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | |
Swell Height Map |  |  |  |  |  |  |  | ||||||||||||||
Wave Height (m) Direction Period (s) | SW 16 | SW 16 | SW 14 | SW 13 | SW 13 | SW 12 | SW 12 | SW 12 | SW 12 | SW 12 | SW 17 | SW 17 | SW 16 | SW 16 | SW 15 | SW 14 | WSW 14 | SW 13 | SW 12 | SW 11 | SW 11 |
Wave Graph  | |||||||||||||||||||||
 kJ | 10886 | 7127 | 3438 | 1619 | 1210 | 786 | 565 | 435 | 435 | 349 | 1837 | 2442 | 1899 | 1281 | 940 | 928 | 1748 | 3145 | 1280 | 866 | 422 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | cross-off | cross-off | cross | cross-on | on | cross | on | cross-on | on | cross-on | on | on | cross-on | cross-on | cross | cross | cross | cross | cross-off |
High Tide | 11:49AM1.99m | 11:02PM1.78m | 12:40PM2.07m | 00:06AM1.81m | 1:23PM2.15m | 1:03AM1.87m | 2:01PM2.23m | 1:54AM1.94m | 2:35PM2.28m | 2:41AM2.02m | 3:07PM2.31m | 3:24AM2.10m | 3:38PM2.33m | ||||||||
Low Tide | 5:43PM1.17m | 5:42AM0.52m | 6:42PM1.07m | 6:34AM0.50m | 7:30PM0.94m | 7:21AM0.48m | 8:11PM0.80m | 8:05AM0.47m | 8:48PM0.66m | 8:45AM0.49m | 9:23PM0.53m | 9:24AM0.52m | 9:57PM0.40m | ||||||||
 |  |  | |  |  |  | |  | | | | | |  | | | | | |  | |
 | 7:24 | — | — | 7:22 | — | — | 7:22 | — | — | 7:20 | — | — | 7:20 | — | — | 7:20 | — | — | 7:18 | — | — |
 | — | 5:27 | — | — | 5:28 | — | — | 5:29 | — | — | 5:30 | — | — | 5:30 | — | — | 5:30 | — | — | 5:31 | — |
mm | 2 | 2 | 3 | 1 | — | 1 | — | — | — | — | — | — | — | — | — | — | 1 | 4 | 1 | — | — |
Temp °C | 12 | 12 | 11 | 12 | 12 | 12 | 11 | 12 | 12 | 12 | 14 | 13 | 12 | 14 | 12 | 11 | 11 | 11 | 11 | 11 | 12 |
Feels °C | 1 | 2 | 3 | 6 | 6 | 7 | 9 | 10 | 10 | 7 | 9 | 9 | 4 | 6 | 4 | 2 | 1 | 1 | 4 | 4 | 8 |
Swell 1 Height (m) Direction Period (s) | — | SSW 16 | SSW 15 | SW 13 | SW 13 | SW 12 | SW 12 | SW 12 | SW 12 | SW 12 | SW 17 | SW 17 | SW 16 | SW 16 | SW 15 | SW 14 | WSW 15 | — | SW 12 | SW 11 | SW 11 |
| kJ | — | 138 | 42 | 1619 | 1210 | 786 | 565 | 435 | 435 | 349 | 1837 | 2442 | 1899 | 1281 | 940 | 928 | 568 | — | 1280 | 866 | 422 |
Swell 2 Height (m) Direction Period (s) | — | — | — | S 9 | — | SW 24 | WSW 21 | SW 20 | SW 19 | SW 18 | SSW 17 | SSW 17 | SSW 16 | SSW 15 | SSW 15 | WSW 5 | — | — | S 16 | SW 21 | SW 20 |
| kJ | — | — | — | 194 | — | 22 | 45 | 61 | 131 | 300 | 168 | 313 | 147 | 135 | 71 | 20 | — | — | 5 | 71 | 315 |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | — | S 21 | S 20 | S 19 | SSW 17 | SE 13 | — | — | — | — | — | — | — | — | S 16 | SW 15 |
| kJ | — | — | — | — | — | — | 9 | 8 | 7 | 58 | 6 | — | — | — | — | — | — | — | — | 5 | 33 |
Wind waves Height (m) Direction Period (s) | SW 16 | SW 16 | SW 14 | — | SW 13 | — | — | — | — | — | — | NNW 4 | NNW 3 | N 3 | NNW 3 | WNW 4 | WSW 14 | SW 13 | — | — | — |
| kJ | 10886 | 7127 | 3438 | — | 732 | — | — | — | — | — | — | 7 | 9 | 5 | 6 | 29 | 1748 | 3145 | — | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 313 | 304 | 68 | 60 | 9 | 4 | 2 | 0 | 2 | 9 | 2 | 9 | 23 | 75 | 68 | 83 | 453 | 72 | 72 | 69 | 9 |
Best forecast wave conditions in Phillip Island | |||||||||||||||||||||
Best forecast wave conditions in Australia | |||||||||||||||||||||
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Information about the Cat Bay (Shelly Beach) Surf forecast
The above surf forecast table for Cat Bay (Shelly Beach) provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Cat Bay (Shelly Beach) can be found by selecting the local surf guide option on the grey menu. Our Cat Bay (Shelly Beach) surf forecast is unique since it includes wave energy (power) that defines the real feel of the surf rather than just the height or the period. If you surf the same spot (Cat Bay (Shelly Beach)) regularly then make a mental note of the wave energy from the surf forecast table each time you go. Very soon you may start to choose your surf days based on the wave energy alone combined with our forecast of favourable offshore wind conditions. Our star ratings will help here and of course you will also find the usual wave height and period predictions on our surf forecasts as well as a full break down of the swell components under our advanced users option (to reveal that, click the little Einstein character under the tide times).
Further information to help with frequently asked questions about our surf forecast for Cat Bay (Shelly Beach) may be found under the help tab on the top menu and also by moving your mouse over the question marks on the surf forecast table itself. Please always bear in mind that the forecast is for near-shore open water and local factors at each surf break influence the actual breaking wave height, such as the beach / reef profile, water depths offshore and shelter.
Cat Bay is 34 km (21 miles) from Mornington. If you plan a holiday in Phillip Island, look for hotels and other accommodation in Mornington. Mornington has rooms for a wide range of budgets as well as car hire and transport links.
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