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:
Mera surfForecast / Chiba / Japan
48hr Weather and Surf, issued 2 am Wednesday 17 Dec 2025 JSTForecast update in hr min s Forecast update imminent
Mera surf forecast is for near shore open water. Breaking waves will often be smaller at less exposed spots.
Today's Mera sea temperature is
19.9° C
(Which is normal for this time of year)How big are the waves at Mera today?
The current surf forecast for Mera at 9AM is: 1.6m 6s primary swell from a West direction and 0.9m 6s secondary swell from a West-southwest direction (forecast issued at 02:00am December 17). An open ocean swell of 0.3m 12s is not directed at the surf break. The wind direction is predicted to be cross-offshore and the swell rating is 2.
| Time (JST) & Date | Wave Height | Wave Period |
|---|---|---|
| Morning (17 Dec) | 5ft (1.6m) | 6s |
| Afternoon (17 Dec) | 4ft (1.2m) | 6s |
| Evening (17 Dec) | 5ft (1.6m) | 6s |
Table - waves today at Mera. (Swell directed towards the surf break)
Updates in hr min s Forecast update imminent
Wednesday 17 | Thursday 18 | Friday 19 | ||||||||||||||||||||||
| 0 AM | 3 AM | 6 AM | 9 AM | 12 PM | 3 PM | 6 PM | 9 PM | 0 AM | 3 AM | 6 AM | 9 AM | 12 PM | 3 PM | 6 PM | 9 PM | 0 AM | 3 AM | 6 AM | 9 AM | 12 PM | 3 PM | 6 PM | 9 PM | |
Rating (10 max) | ||||||||||||||||||||||||
Swell Height Map |    |    |    | |||||||||||||||||||||
| Wave Height (m) & direction (?) | ||||||||||||||||||||||||
| Period(s) (?) | 7 | 7 | 7 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 10 | 11 | 11 | 5 | 11 | 5 |
Wave (?)Graph  | ||||||||||||||||||||||||
 kJ (?) | 198 | 158 | 158 | 184 | 60 | 103 | 129 | 160 | 122 | 61 | 53 | 39 | 32 | 24 | 14 | 14 | 10 | 6 | 10 | 11 | 11 | 17 | 11 | 42 |
Wind (km/h) | ||||||||||||||||||||||||
| Wind State (?) onshore cross-onshore cross-shore cross-offshore offshore glassy | cross- on | cross- on | cross- off | cross- off | cross- on | cross- on | on | cross- on | cross- on | cross- off | off | off | off | off | cross- off | cross- off | cross- off | cross- off | off | cross- off | cross- off | glass | on | cross- on |
High Tide / height (m) | 3:52AM 1.22 | 1:53PM 1.37 | 4:32AM 1.29 | 2:32PM 1.40 | 5:08AM 1.33 | 3:08PM 1.42 | ||||||||||||||||||
Low Tide / height (m) | 8:29AM 0.94 | 9:18PM 0.16 | 9:16AM 0.95 | 9:53PM 0.08 | 9:58AM 0.94 | |||||||||||||||||||
Wednesday 17 | Thursday 18 | Friday 19 | ||||||||||||||||||||||
| Sunrise | - | - | - | 6:41 | - | - | - | - | - | - | - | 6:41 | - | - | - | - | - | - | - | 6:41 | - | - | - | - |
| Sunset | - | - | - | - | - | 4:30 | - | - | - | - | - | - | - | 4:30 | - | - | - | - | - | - | - | 4:30 | - | - |
 |  | |  |  | | | | | | | | | | |  | | | | | | | |  | |
Rain (mm) | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | 1 |
| Temp. °C | 12 | 12 | 11 | 11 | 12 | 13 | 14 | 15 | 15 | 11 | 10 | 10 | 11 | 12 | 12 | 12 | 12 | 13 | 13 | 12 | 12 | 13 | 15 | 16 |
| Feels °C (?) | 7 | 8 | 8 | 7 | 8 | 8 | 5 | 7 | 8 | 3 | 3 | 3 | 5 | 7 | 7 | 8 | 9 | 11 | 11 | 9 | 9 | 12 | 14 | 12 |
- Map Icons:
Break
Live Wave Height (m)
Live Wind Speed (km/h)
Surf Rating (10 Max)
Ocean Swells (m)- Wind Speed (km/h)
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