Shonan is a highly populated, expansive beach break area situated along Sagami Bay in Kanagawa Prefecture, Japan. The underlying bathymetry consists of dark, volcanic silica sandbanks that are heavily influenced by river outflows and coastal groynes.
Forecast accuracy at Shonan
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Best time to go
No great windows in the next 2 days
Best available option is Today around 11am (score: 8). Conditions are below the Good threshold but may still be surfable.
Crowd report
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Session journal
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7-day forecastRecent form
Last 15 days of logged conditions.
Best time to visit Shonan
Combining historical conditions with school holiday crowd pressure to find the sweet spot.
Key insights
- The best week for surf at Shonan is the week of 4 May (score 3/5) with low crowds.
Best time to visit
Crowd calendar
How busy each week is based on school holiday overlap from feeder markets.
School holidays affecting this destination
How are these scores calculated?
The timing score combines two signals: historical conditions quality (how good the skiing or surfing typically is in a given week, based on 5 years of weather data) and crowd pressure (how many of this destination's feeder markets have school holidays that week).
Crowd pressure is weighted by each feeder country's share of visitors. If 40% of a resort's visitors come from France and France is on holiday, that contributes 0.40 to the crowd pressure score. Crowds can reduce the timing score by up to 35%, ensuring conditions still matter most.
Scores: 5 = great conditions with low crowds (the sweet spot). 4 = great conditions with moderate crowds, or good conditions with low crowds. 3 = average. 2 = below average conditions or very crowded. 1 = poor conditions or peak holiday chaos.
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Create Profile →Frequently asked questions
How often is this page updated?
Current conditions refresh every 3 hours when the cron runs. Hourly data updates every 30 minutes. The 7-day forecast, luck factor, and packing notes are all pre-computed at the same time.
What is the luck factor?
We compare the 7-day forecast to the last 5 years of marine data for the same week at Shonan. The delta tells you whether conditions are shaping up better, worse, or about the same as a typical early May.
How is 'best session' picked?
We score each day of the 7-day forecast using the same algorithm as the leaderboard, and highlight the highest scorer.
Where does the data come from?
Open-Meteo's Marine API (swell height, period, water temperature) and Weather API (wind and conditions).
Does the score capture local knowledge?
Honestly, no. Every break has tide windows, swell directions and reef contours that a global model cannot see. Treat the score as a starting point, then check a local cam.
When is the best time to surf Shonan?
The best week for surf at Shonan is the week of 4 May (score 3/5) with low crowds.