Nazare Big Wave Challenge Gets Yellow Alert, Could Run Saturday in Giant Waves
70-foot plus waves predicted for Portuguese big wave tow surfing competition.
Surf Forecasts:
Portsea Back Beach surfForecast / VIC – Mornington Peninsula / Australia
48hr Weather and Surf, issued 4 pm Wednesday 17 Dec 2025 AEDTForecast update in hr min s Forecast update imminent
Portsea Back Beach surf forecast is for near shore open water. Breaking waves will often be smaller at less exposed spots.
Today's Portsea Back Beach sea temperature is
16.0° C
(Which is normal for this time of year)How big are the waves at Portsea Back Beach today?
The current surf forecast for Portsea Back Beach at 6PM is: 0.9m 10s primary swell from a Southwest direction and 0.3m 15s secondary swell from a Southwest direction, 0.3m 2s secondary swell from a South-southeast direction (forecast issued at 04:00pm December 17). The wind direction is predicted to be cross-onshore.
| Time (AEDT) & Date | Wave Height | Wave Period |
|---|---|---|
| Morning (17 Dec) | - | - |
| Afternoon (17 Dec) | 3.5ft (1.1m) | 10s |
| Evening (17 Dec) | 3ft (0.9m) | 10s |
Table - waves today at Portsea Back Beach. (Swell directed towards the surf break)
Updates in hr min s Forecast update imminent
Wednesday 17 | Thursday 18 | Friday 19 | Saturday 20 | |||||||||||||||||||||
| 2 PM | 5 PM | 8 PM | 11 PM | 2 AM | 5 AM | 8 AM | 11 AM | 2 PM | 5 PM | 8 PM | 11 PM | 2 AM | 5 AM | 8 AM | 11 AM | 2 PM | 5 PM | 8 PM | 11 PM | 2 AM | 5 AM | 8 AM | 11 AM | |
Rating (10 max) | ||||||||||||||||||||||||
Swell Height Map |    |    |    |    | ||||||||||||||||||||
| Wave Height (m) & direction (?) | ||||||||||||||||||||||||
| Period(s) (?) | 10 | 10 | 10 | 9 | 9 | 10 | 10 | 10 | 11 | 11 | 11 | 13 | 13 | 12 | 12 | 12 | 12 | 11 | 11 | 11 | 11 | 11 | 10 | 10 |
Wave (?)Graph  | ||||||||||||||||||||||||
 kJ (?) | 226 | 170 | 167 | 106 | 84 | 108 | 136 | 156 | 198 | 153 | 155 | 173 | 320 | 252 | 248 | 240 | 228 | 217 | 205 | 194 | 194 | 137 | 110 | 84 |
Wind (km/h) | ||||||||||||||||||||||||
| Wind State (?) onshore cross-onshore cross-shore cross-offshore offshore glassy | cross | cross- on | cross | cross | glass | cross- off | cross- off | cross | cross- on | cross | cross- off | glass | cross- off | cross- off | cross- on | glass | cross- off | off | cross- off | cross- on | on | on | cross- on | on |
High Tide / height (m) | 11:19PM 1.22 | 10:05AM 1.17 | 12:18AM 1.28 | 10:59AM 1.15 | 1:08AM 1.35 | |||||||||||||||||||
Low Tide / height (m) | 4:10PM 0.36 | 4:47AM 0.85 | 5:03PM 0.33 | 6:01AM 0.84 | 5:53PM 0.28 | 7:05AM 0.79 | ||||||||||||||||||
Wednesday 17 | Thursday 18 | Friday 19 | Saturday 20 | |||||||||||||||||||||
| Sunrise | - | - | - | - | - | - | 5:52 | - | - | - | - | - | - | - | 5:52 | - | - | - | - | - | - | - | 5:52 | - |
| Sunset | - | - | 8:40 | - | - | - | - | - | - | - | 8:42 | - | - | - | - | - | - | - | 8:43 | - | - | - | - | - |
 | | |  | | | | | | |  |  | | |  | | | | | | | |  | | |
Rain (mm) | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | 1 | - |
| Temp. °C | 25 | 24 | 23 | 22 | 21 | 20 | 21 | 29 | 23 | 22 | 24 | 24 | 22 | 22 | 22 | 24 | 24 | 27 | 25 | 21 | 17 | 16 | 15 | 17 |
| Feels °C (?) | 22 | 19 | 20 | 20 | 20 | 19 | 18 | 26 | 17 | 18 | 22 | 22 | 19 | 19 | 20 | 22 | 21 | 22 | 22 | 18 | 16 | 14 | 13 | 15 |
- Map Icons:
Break
Live Wave Height (m)
Live Wind Speed (km/h)
Surf Rating (10 Max)
Ocean Swells (m)- Wind Speed (km/h)
Latest Updates
Buy Less, Surf More This Black Friday
Surf-forecast is providing a free, all-access pass to our premium features and 12-day forecasts all weekend.
Quiksilver Teams Up With PrimaLoft® For World’s First Thermal Layering System for a Wetsuit.
Previously used in our snow jackets for mountain conditions, PrimaLoft® technology is making its debut in the surf industry. The aim is to bring mountain-grade warmth to the waves.
Vancouver Island’s Day Of Days With Reed Platenius
Surf-Forecast recently helped the 21-year-old Canadian pro surfer and adventurer score some cold water perfection at home.
Read more
Discover more articles and updates in the Greenroom.
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 Portsea Back 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.
Nearest