Surf Forecasts:
Cat Bay (Shelly Beach) surf forecast from 12 Sep 2026:
- Best quality surf: Thursday 17 Sep, 1PM (local time) - 6.5ft (2.0m), 14s period, SW swell with cross-offshore winds.
- Most powerful swell: Tuesday 15 Sep, 7PM (local time) - 11ft (3.5m), 14s period, SW swell with 4,766 kJ wave energy.
- Next surfable swell (1★+): Thursday 17 Sep, 1PM (local time) - 6.5ft (2.0m), 14s 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 Thursday (Sep 17) at 1PM. The primary swell is predicted to be 2.0m and 14s period. 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 3.5m 14s and forecast to arrive on Tuesday (Sep 15) at 7PM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.0m 5s period and expected on Tuesday (Sep 15) at 1AM.
| Wave Type | Time (AEST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 1PM (Thu 17th Sep) | 6.5ft (2.0m) 14s |
| Best Surf | 1PM (Thu 17th Sep) | 6.5ft (2.0m) 14s |
| Most Powerful | 7PM (Tue 15th Sep) | 11ft (3.5m) 14s |
Table - best surf conditions forecast for Cat Bay (Shelly Beach) over the next 16 days.
The Lowdown
G’day, Rusty here. Let’s look at Cat Bay (Shelly Beach) over the next 16 days. It’s a long-range forecast, so strap in—there’s some proper waiting involved.
First week is mostly a bust. Sunday the 13th starts with a 5 ft SW swell and combined energy of 1103 (moderate to strong), but a 30 km/h N wind has it messy. Sunday afternoon stays junk with 5 ft and the same wind. Monday the 14th is cross-onshore and choppy with 3 ft. Tuesday the 15th jumps to 8 ft SW swell (2004 energy) but a strong 40 km/h WSW cross-breeze ruins it. Tuesday afternoon cleans up with 12 ft SW swell (3809 energy) and cross-offshore wind, but at that size it’s expert-only.
Wednesday the 16th has 10 ft SW swell (6584 energy) and clean cross-offshore winds, but the wave comment says “marginal surf forecast or questionable tide conditions”—3/10 score. Thursday the 17th morning stays clean with 7 ft SW swell (1973 energy), still marginal. By afternoon, 6 ft SW swell (1262 energy) and 15 km/h SW cross-offshore wind, “expect very good surf conditions” but only a 3/10. Crowds are “often,” so expect a full lineup.
Then a gap from Friday the 18th to Sunday the 20th—all onshore junk, no recommendations.
Monday the 21st is the first clean window: glassy calm with 8 ft SW swell (1909 energy), long 13-second period. Scores 3/10, but that flat calm wind is gold. Not a standout, but a nice start.
Tuesday the 22nd is the first true standout. Morning: 12 ft SW swell (6068 energy), 16-second period, gentle cross-offshore breeze. “Excellent for experienced surfers” at 5/10. Afternoon: 10 ft SW swell (4847 energy) with fresh 30 km/h SSE offshore—also clean. Over 8 ft, it’s only for experts. Crowds likely.
Wednesday the 23rd: morning has 7 ft SW swell (2166 energy) with light cross-onshore, small ripples. But afternoon is 7 ft SW swell (2574 energy), 16-second period, gentle SSE offshore—clean, 4/10, excellent for experienced surfers.
Thursday the 24th is a big standout. Morning: 10 ft SW swell (6448 energy) with a 19-second period—very long-period groundswell, incredible energy. Light onshore breeze, 4/10, but tide may be tricky. Afternoon: 8 ft SW swell (5153 energy), 18-second period, light SE offshore wind. “Excellent for experienced surfers” at 4/10—clean, powerful, expert-only. Crowds are “often.”
Friday the 25th drops to 6 ft SW swell (1565 energy) with choppy cross-onshore, 1/10. Saturday the 26th is small: 4 ft SW swell (633 energy) morning, cleaning to 4 ft by afternoon with 15 km/h SW cross-offshore, 2/10 for “expect good surf conditions.”
Sunday the 27th: morning 10 ft WSW swell (1758 energy), 10-second period, gentle SSE offshore—clean, 3/10. Afternoon: 13 ft SW swell (3998 energy) with moderate 25 km/h S offshore, “excellent for experienced surfers” at 4/10. Monday the 28th finishes huge: 15 ft SW swell (9304 energy), 16-second period, near-calm wind, “excellent for experienced surfers” at 5/10—the biggest, cleanest swell of the run, but a long way off.
Water temps are about average for the season. Best sessions for experts: Tuesday the 22nd afternoon, Thursday the 24th afternoon, and Monday the 28th morning. If you’re not an expert, wait for the smaller clean windows around the 26th.
Stay salty,
Rusty
Short Range ForecastLight rain (total 3mm), mostly falling on Mon night. Warm (max 21°C on Sun morning, min 10°C on Tue afternoon). Winds increasing (light winds from the NNE on Sat night, strong winds from the SW by Tue afternoon). | Days 5-7 Weather SummaryMostly dry. Very mild (max 19°C on Fri afternoon, min 8°C on Thu night). Winds decreasing (strong winds from the SSW on Tue night, light winds from the WSW by Thu night). | ||||||||||||||||||
Sunday 13 | Monday 14 | Tuesday 15 | Wednesday 16 | Thursday 17 | Friday 18 | ||||||||||||||
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 15 | SW 14 | SW 15 | SW 14 | SW 14 | SW 13 | SW 13 | SW 13 | SW 14 | SW 14 | SW 15 | SW 15 | SW 15 | SW 14 | SW 14 | SW 13 | SW 13 | SW 17 | SW 15 |
Wave Graph  | |||||||||||||||||||
 kJ | 1279 | 1006 | 927 | 598 | 357 | 295 | 130 | 1651 | 3809 | 4308 | 3936 | 3678 | 2982 | 1855 | 1262 | 933 | 778 | 618 | 1432 |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | on | on | cross-on | cross-on | cross-off | cross | cross | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-on | on | cross-on | on |
High Tide | 00:42AM2.17m | 1:04PM2.24m | 1:37AM2.28m | 1:46PM2.28m | 2:25AM2.36m | 2:26PM2.30m | 3:08AM2.39m | 3:03PM2.30m | 3:48AM2.37m | 3:38PM2.27m | 4:26AM2.32m | 4:12PM2.21m | |||||||
Low Tide | 6:53AM0.53m | 7:20PM0.40m | 7:43AM0.54m | 8:04PM0.27m | 8:28AM0.56m | 8:45PM0.19m | 9:09AM0.59m | 9:23PM0.17m | 9:46AM0.64m | 9:59PM0.19m | 10:22AM0.71m | 10:35PM0.25m | |||||||
 |  | |  |  | |  |  | | | | | |  | | | | | | |
 | — | 6:24 | — | — | 6:22 | — | — | 6:20 | — | — | 6:18 | — | — | 6:18 | — | — | 6:16 | — | — |
 | — | — | 6:07 | — | — | 6:07 | — | — | 6:08 | — | — | 6:08 | — | — | 6:09 | — | — | 6:10 | — |
mm | — | — | — | — | — | — | 1 | 1 | 1 | — | — | — | — | — | — | — | — | — | — |
Temp °C | 18 | 21 | 21 | 20 | 15 | 14 | 15 | 12 | 11 | 11 | 11 | 11 | 11 | 9 | 10 | 10 | 15 | 19 | 15 |
Feels °C | 16 | 15 | 15 | 17 | 12 | 9 | 10 | 3 | 0 | 0 | 3 | 4 | 5 | 5 | 7 | 7 | 10 | 15 | 9 |
Swell 1 Height (m) Direction Period (s) | SW 15 | SW 14 | SW 15 | SW 14 | SW 14 | SW 13 | SW 13 | SW 16 | — | SSW 15 | SW 15 | SW 15 | SW 15 | SW 14 | SW 14 | SW 13 | SW 13 | SW 13 | SW 15 |
| kJ | 1279 | 1006 | 927 | 598 | 357 | 295 | 130 | 353 | — | 169 | 3936 | 3678 | 2982 | 1855 | 1262 | 933 | 778 | 618 | 1432 |
Swell 2 Height (m) Direction Period (s) | SSW 15 | SSW 15 | SSW 16 | NNW 3 | SW 20 | WSW 19 | SW 18 | — | — | — | — | — | — | SSW 14 | — | SW 21 | SW 18 | SW 17 | — |
| kJ | 93 | 88 | 24 | 3 | 15 | 37 | 111 | — | — | — | — | — | — | 118 | — | 71 | 463 | 530 | — |
Swell 3 Height (m) Direction Period (s) | — | — | — | SSW 15 | — | S 14 | — | — | — | — | — | — | — | — | — | S 22 | SSW 18 | SSW 17 | — |
| kJ | — | — | — | 22 | — | 4 | — | — | — | — | — | — | — | — | — | 9 | 66 | 164 | — |
Wind waves Height (m) Direction Period (s) | — | NNW 3 | NNW 4 | — | NW 2 | SW 4 | WSW 5 | SW 13 | SW 14 | SW 14 | SW 15 | SW 15 | SSW 6 | — | — | — | NW 3 | NW 4 | NW 3 |
| kJ | — | 9 | 10 | — | 1 | 8 | 44 | 1651 | 3809 | 4308 | 2648 | 2425 | 112 | — | — | — | 2 | 3 | 7 |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 9 | 13 | 11 | 9 | 2 | 68 | 83 | 524 | 659 | 263 | 313 | 126 | 0 | 0 | 0 | 2 | 6 | 4 | 10 |
Best forecast wave conditions in Phillip Island | |||||||||||||||||||
Best forecast wave conditions in Australia | |||||||||||||||||||
Header Global | |||||||||||||||||||
- Map Icons:
Break
Live Wave Height (m)
Live Wind Speed (km/h)
Surf Rating (10 Max)
Ocean Swells (m)- Wind Speed (km/h)
FREE! Surf-Forecast.com widget for your website
The surf report / weather widget below is available to embed on third party websites free of charge and provides a summary of our Cat Bay (Shelly Beach) surf forecast. Simply grab the html code snippet that we provide and paste it into your own site. You can choose your preferred language and metric/imperial units for the surf forecast feed to suit users of your site. Click here to get the code.
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.
Nearest