Surf Forecast for Tsurigasaki Beach (Shidashita)
type: Dataset
description: 10-day surf forecast with Strike Scores for Tsurigasaki Beach (Shidashita), Ichinomiya, Japan
about: Tsurigasaki Beach (Shidashita)
  type: TouristAttraction
  geo: GeoCoordinates
    latitude: 35.3736
    longitude: 140.3847
  description: Tsurigasaki Beach, locally known as Shidashita, made history as the venue for surfing's Olympic debut at the Tokyo 2020 Games. Located on Chiba's Kujukuri coast, this exposed beachbreak acts as a catcher's mitt for swells from the north, east, and south. The shifting sandbars produce peaks that can get hollow during typhoon swells, and the competitive atmosphere has produced many of Japan's best surfers. Its proximity to Tokyo makes it crowded on weekends, but the quality and consistency justify its world-class status.
summary:
  best day:
    date: 2026-08-09
    score: 86
    category: Firing
    explanation: Best day in the forecast: 2026-08-09 with a score of 86/100 (Firing)
  firing days count: 1
  firing days:
    date: 2026-08-09
    score: 86
  overall recommendation: Moderate recommendation: Tsurigasaki Beach (Shidashita) has 1 Firing day(s) and 1 Good day(s). Worth considering.
forecasts:
  date: 2026-08-05
  day index: 0
  strike score:
    final score: 13
    category: Poor
    category emoji: 💤
    confidence: 1
    confidence explanation: Very high confidence (0-1 day forecast)
    breakdown:
      swell direction:
        score: 15
        out of: 25
        explanation: Moderate alignment: Swell from 133° is 23° off optimal 110°, workable but not ideal.
      swell size:
        score: 2
        out of: 25
        explanation: Too big: 4.0m exceeds maximum 2.5m. Risk of closeouts.
      swell period:
        score: 23
        out of: 25
        explanation: Good period: 15s is 125% of ideal 12s. Clean, powerful groundswell.
      wind:
        score: 0
        out of: 25
        explanation: Onshore/cross-shore: 19 km/h from 27° (NNE). Destroying wave quality. Offshore range: 210°-290°.
    adjustments:
      wind history:
        adjustment: -17
        groomed: false
        morning sickness: true
        explanation: -17 points: Previous days of onshore wind left residual chop ("morning sickness"), reducing wave quality.
      windswell penalty:
        adjustment: 0
        windswell degraded: false
        explanation: Groundswell-dominant conditions (clean, long-period waves).
      secondary swell bonus:
        adjustment: 0
        explanation: No secondary swell bonus.
    summary: Poor conditions at Tsurigasaki Beach (Shidashita). Either swell direction (133°), size (4.0m), or wind (19 km/h from 27°) is unfavorable. Consider other spots or wait for better conditions.
  conditions:
    swell:
      height m: 4
      height ft: 13.1
      direction degrees: 133
      direction cardinal: SE
      period s: 15
      explanation: 4.0m (13.1ft) swell from 133° (SE) at 15s period
    wind:
      speed kmh: 19
      speed mph: 11.8
      direction degrees: 27
      direction cardinal: NNE
      explanation: 19 km/h (12 mph) from 27° (NNE)
    windswell:
      height m: 0.5
      period s: 3
      explanation: Local wind-generated waves (choppy, short-period)
forecasts:
  date: 2026-08-06
  day index: 1
  strike score:
    final score: 55
    category: Fair
    category emoji: 😐
    confidence: 1
    confidence explanation: Very high confidence (0-1 day forecast)
    breakdown:
      swell direction:
        score: 8
        out of: 25
        explanation: Poor alignment: Swell from 159° is 49° off optimal 110°, barely within workable range 45°-155°.
      swell size:
        score: 17
        out of: 25
        explanation: Marginal size: 2.5m is 0.9m from ideal 1.6m.
      swell period:
        score: 25
        out of: 25
        explanation: Perfect period: 13s is at or above ideal 12s. Long-period groundswell with maximum power.
      wind:
        score: 13
        out of: 25
        explanation: Onshore/cross-shore: 8 km/h from 81° (E). Destroying wave quality. Offshore range: 210°-290°.
    adjustments:
      wind history:
        adjustment: -11
        groomed: false
        morning sickness: true
        explanation: -11 points: Previous days of onshore wind left residual chop ("morning sickness"), reducing wave quality.
      windswell penalty:
        adjustment: 0
        windswell degraded: false
        explanation: Groundswell-dominant conditions (clean, long-period waves).
      secondary swell bonus:
        adjustment: 0
        explanation: No secondary swell bonus.
    summary: Surfable but not special at Tsurigasaki Beach (Shidashita). The 2.5m swell from 159° is workable, but conditions aren't ideal. Fine if you're local, but not worth a dedicated trip.
  conditions:
    swell:
      height m: 2.5
      height ft: 8.2
      direction degrees: 159
      direction cardinal: SSE
      period s: 13
      explanation: 2.5m (8.2ft) swell from 159° (SSE) at 13s period
    wind:
      speed kmh: 8
      speed mph: 5.0
      direction degrees: 81
      direction cardinal: E
      explanation: 8 km/h (5 mph) from 81° (E)
    secondary swell:
      height m: 1
      direction degrees: 109
      direction cardinal: ESE
      period s: 8
forecasts:
  date: 2026-08-07
  day index: 2
  strike score:
    final score: 56
    category: Fair
    category emoji: 😐
    confidence: 0.95
    confidence explanation: High confidence (2-3 day forecast)
    breakdown:
      swell direction:
        score: 13
        out of: 25
        explanation: Moderate alignment: Swell from 138° is 28° off optimal 110°, workable but not ideal.
      swell size:
        score: 22
        out of: 25
        explanation: Good size: 2.1m is within 15% of ideal 1.6m.
      swell period:
        score: 14
        out of: 25
        explanation: Moderate period: 10s meets minimum 8s but below ideal 12s. Some groundswell energy present.
      wind:
        score: 11
        out of: 25
        explanation: Onshore/cross-shore: 9 km/h from 117° (ESE). Destroying wave quality. Offshore range: 210°-290°.
    adjustments:
      wind history:
        adjustment: -4
        groomed: false
        morning sickness: false
        explanation: No significant wind history adjustment.
      windswell penalty:
        adjustment: 0
        windswell degraded: false
        explanation: Groundswell-dominant conditions (clean, long-period waves).
      secondary swell bonus:
        adjustment: 0
        explanation: No secondary swell bonus.
    summary: Surfable but not special at Tsurigasaki Beach (Shidashita). The 2.1m swell from 138° is workable, but conditions aren't ideal. Fine if you're local, but not worth a dedicated trip.
  conditions:
    swell:
      height m: 2.1
      height ft: 6.9
      direction degrees: 138
      direction cardinal: SE
      period s: 10
      explanation: 2.1m (6.9ft) swell from 138° (SE) at 10s period
    wind:
      speed kmh: 9
      speed mph: 5.6
      direction degrees: 117
      direction cardinal: ESE
      explanation: 9 km/h (6 mph) from 117° (ESE)
    secondary swell:
      height m: 0.6
      direction degrees: 191
      direction cardinal: S
      period s: 11
forecasts:
  date: 2026-08-08
  day index: 3
  strike score:
    final score: 62
    category: Fair
    category emoji: 😐
    confidence: 0.92
    confidence explanation: High confidence (2-3 day forecast)
    summary: Surfable but not special at Tsurigasaki Beach (Shidashita). The 1.8m swell from 125° is workable, but conditions aren't ideal. Fine if you're local, but not worth a dedicated trip.
provider: Strike Mission
date published: 2026-08-05T00:34:26.232Z
temporal coverage: 2026-08-05/2026-08-14
data sources: Open-Meteo Marine API (swell/wave data)
data sources: Open-Meteo Weather API (wind/weather data)

swell direction:
  score: 18
  out of: 25
  explanation: Moderate alignment: Swell from 125° is 15° off optimal 110°, workable but not ideal.
swell size:
  score: 20
  out of: 25
  explanation: Good size: 1.8m is within 15% of ideal 1.6m.
swell period:
  score: 25
  out of: 25
  explanation: Perfect period: 12s is at or above ideal 12s. Long-period groundswell with maximum power.
wind:
  score: 7
  out of: 25
  explanation: Onshore/cross-shore: 12 km/h from 156° (SSE). Destroying wave quality. Offshore range: 210°-290°.

wind history:
  adjustment: 0
  groomed: false
  morning sickness: false
  explanation: No significant wind history adjustment.
windswell penalty:
  adjustment: 0
  windswell degraded: false
  explanation: Groundswell-dominant conditions (clean, long-period waves).
secondary swell bonus:
  adjustment: 0
  explanation: No secondary swell bonus.

swell:
  height m: 1.8
  height ft: 5.9
  direction degrees: 125
  direction cardinal: SE
  period s: 12
  explanation: 1.8m (5.9ft) swell from 125° (SE) at 12s period
wind:
  speed kmh: 12
  speed mph: 7.5
  direction degrees: 156
  direction cardinal: SSE
  explanation: 12 km/h (7 mph) from 156° (SSE)
secondary swell:
  height m: 0.7
  direction degrees: 182
  direction cardinal: S
  period s: 8

date: 2026-08-09
day index: 4
strike score:
  final score: 86
  category: Firing
  category emoji: 🔥
  confidence: 0.89
  confidence explanation: Moderate confidence (4-5 day forecast)
  breakdown:
    swell direction:
      score: 25
      out of: 25
      explanation: Perfect alignment: Swell from 110° is within 5° of optimal 110°.
    swell size:
      score: 25
      out of: 25
      explanation: Perfect size: 2.0m is at the sweet spot (ideal: 1.6m).
    swell period:
      score: 23
      out of: 25
      explanation: Good period: 15s is 125% of ideal 12s. Clean, powerful groundswell.
    wind:
      score: 15
      out of: 25
      explanation: Onshore/cross-shore: 7 km/h from 115° (ESE). Destroying wave quality. Offshore range: 210°-290°.
  adjustments:
    wind history:
      adjustment: 0
      groomed: false
      morning sickness: false
      explanation: No significant wind history adjustment.
    windswell penalty:
      adjustment: 0
      windswell degraded: false
      explanation: Groundswell-dominant conditions (clean, long-period waves).
    secondary swell bonus:
      adjustment: 0
      explanation: No secondary swell bonus.
  summary: Excellent conditions at Tsurigasaki Beach (Shidashita). The 2.0m swell from 110° aligns well with the spot, and light offshore winds are grooming the face. Worth planning a trip around this.
conditions:
  swell:
    height m: 2
    height ft: 6.6
    direction degrees: 110
    direction cardinal: ESE
    period s: 15
    explanation: 2.0m (6.6ft) swell from 110° (ESE) at 15s period
  wind:
    speed kmh: 7
    speed mph: 4.3
    direction degrees: 115
    direction cardinal: ESE
    explanation: 7 km/h (4 mph) from 115° (ESE)
  secondary swell:
    height m: 0.5
    direction degrees: 187
    direction cardinal: S
    period s: 8

date: 2026-08-10
day index: 5
strike score:
  final score: 69
  category: Good
  category emoji: ✅
  confidence: 0.86
  confidence explanation: Moderate confidence (4-5 day forecast)
  breakdown:
    swell direction:
      score: 19
      out of: 25
      explanation: Moderate alignment: Swell from 98° is 12° off optimal 110°, workable but not ideal.
    swell size:
      score: 20
      out of: 25
      explanation: Good size: 2.2m is within 15% of ideal 1.6m.
    swell period:
      score: 25
      out of: 25
      explanation: Perfect period: 13s is at or above ideal 12s. Long-period groundswell with maximum power.
    wind:
      score: 7
      out of: 25
      explanation: Onshore/cross-shore: 11 km/h from 72° (ENE). Destroying wave quality. Offshore range: 210°-290°.
  adjustments:
    wind history:
      adjustment: 0
      groomed: false
      morning sickness: false
      explanation: No significant wind history adjustment.
    windswell penalty:
      adjustment: 0
      windswell degraded: false
      explanation: Groundswell-dominant conditions (clean, long-period waves).
    secondary swell bonus:
      adjustment: 0
      explanation: No secondary swell bonus.
  summary: Good surfable conditions at Tsurigasaki Beach (Shidashita). 2.2m swell from 98° with manageable wind. Solid session guaranteed.
conditions:
  swell:
    height m: 2.2
    height ft: 7.2
    direction degrees: 98
    direction cardinal: E
    period s: 13
    explanation: 2.2m (7.2ft) swell from 98° (E) at 13s period
  wind:
    speed kmh: 11
    speed mph: 6.8
    direction degrees: 72
    direction cardinal: ENE
    explanation: 11 km/h (7 mph) from 72° (ENE)
  secondary swell:
    height m: 0.5
    direction degrees: 195
    direction cardinal: SSW
    period s: 8
  windswell:
    height m: 0.5
    period s: 3
    explanation: Local wind-generated waves (choppy, short-period)

date: 2026-08-11
day index: 6
strike score:
  final score: 55
  category: Fair
  category emoji: 😐
  confidence: 0.83
  confidence explanation: Low confidence (6-7 day forecast)
  breakdown:
    swell direction:
      score: 21
      out of: 25
      explanation: Good alignment: Swell from 118° is 8° off optimal 110°, still within prime range.
    swell size:
      score: 20
      out of: 25
      explanation: Good size: 2.2m is within 15% of ideal 1.6m.
    swell period:
      score: 25
      out of: 25
      explanation: Perfect period: 13s is at or above ideal 12s. Long-period groundswell with maximum power.
    wind:
      score: 0
      out of: 25
      explanation: Onshore/cross-shore: 21 km/h from 35° (NE). Destroying wave quality. Offshore range: 210°-290°.
  adjustments:
    wind history:
      adjustment: 0
      groomed: false
      morning sickness: false
      explanation: No significant wind history adjustment.
    windswell penalty:
      adjustment: 0
      windswell degraded: false
      explanation: Groundswell-dominant conditions (clean, long-period waves).
    secondary swell bonus:
      adjustment: 0
      explanation: No secondary swell bonus.
  summary: Surfable but not special at Tsurigasaki Beach (Shidashita). The 2.2m swell from 118° is workable, but conditions aren't ideal. Fine if you're local, but not worth a dedicated trip.
conditions:
  swell:
    height m: 2.2
    height ft: 7.2
    direction degrees: 118
    direction cardinal: ESE
    period s: 13
    explanation: 2.2m (7.2ft) swell from 118° (ESE) at 13s period
  wind:
    speed kmh: 21
    speed mph: 13.0
    direction degrees: 35
    direction cardinal: NE
    explanation: 21 km/h (13 mph) from 35° (NE)
  secondary swell:
    height m: 0.4
    direction degrees: 75
    direction cardinal: ENE
    period s: 6
  windswell:
    height m: 0.7
    period s: 3
    explanation: Local wind-generated waves (choppy, short-period)

date: 2026-08-12
day index: 7
strike score:
  final score: 31
  category: Poor
  category emoji: 💤
  confidence: 0.8
  confidence explanation: Low confidence (6-7 day forecast)
  breakdown:
    swell direction:
      score: 18
      out of: 25
      explanation: Moderate alignment: Swell from 95° is 15° off optimal 110°, workable but not ideal.
    swell size:
      score: 8
      out of: 25
      explanation: Too big: 3.0m exceeds maximum 2.5m. Risk of closeouts.
    swell period:
      score: 25
      out of: 25
      explanation: Perfect period: 12s is at or above ideal 12s. Long-period groundswell with maximum power.
    wind:
      score: 0
      out of: 25
      explanation: Onshore/cross-shore: 24 km/h from 28° (NNE). Destroying wave quality. Offshore range: 210°-290°.
  adjustments:
    wind history:
      adjustment: -10
      groomed: false
      morning sickness: true
      explanation: -10 points: Previous days of onshore wind left residual chop ("morning sickness"), reducing wave quality.
    windswell penalty:
      adjustment: 0
      windswell degraded: false
      explanation: Groundswell-dominant conditions (clean, long-period waves).
    secondary swell bonus:
      adjustment: 3
      explanation: +3 points: Secondary swell from a favorable direction enhances wave shape at this spot.
  summary: Poor conditions at Tsurigasaki Beach (Shidashita). Either swell direction (95°), size (3.0m), or wind (24 km/h from 28°) is unfavorable. Consider other spots or wait for better conditions.
conditions:
  swell:
    height m: 3
    height ft: 9.8
    direction degrees: 95
    direction cardinal: E
    period s: 12
    explanation: 3.0m (9.8ft) swell from 95° (E) at 12s period
  wind:
    speed kmh: 24
    speed mph: 14.9
    direction degrees: 28
    direction cardinal: NNE
    explanation: 24 km/h (15 mph) from 28° (NNE)
  secondary swell:
    height m: 0.7
    direction degrees: 74
    direction cardinal: ENE
    period s: 6
  windswell:
    height m: 0.9
    period s: 4
    explanation: Local wind-generated waves (choppy, short-period)

date: 2026-08-13
day index: 8
strike score:
  final score: 33
  category: Poor
  category emoji: 💤
  confidence: 0.8
  confidence explanation: Very low confidence (8-10 day forecast, conditions may change)
  breakdown:
    swell direction:
      score: 14
      out of: 25
      explanation: Moderate alignment: Swell from 85° is 25° off optimal 110°, workable but not ideal.
    swell size:
      score: 17
      out of: 25
      explanation: Marginal size: 2.5m is 0.9m from ideal 1.6m.
    swell period:
      score: 25
      out of: 25
      explanation: Perfect period: 12s is at or above ideal 12s. Long-period groundswell with maximum power.
    wind:
      score: 0
      out of: 25
      explanation: Onshore/cross-shore: 26 km/h from 17° (NNE). Destroying wave quality. Offshore range: 210°-290°.
  adjustments:
    wind history:
      adjustment: -17
      groomed: false
      morning sickness: true
      explanation: -17 points: Previous days of onshore wind left residual chop ("morning sickness"), reducing wave quality.
    windswell penalty:
      adjustment: 0
      windswell degraded: false
      explanation: Groundswell-dominant conditions (clean, long-period waves).
    secondary swell bonus:
      adjustment: 3
      explanation: +3 points: Secondary swell from a favorable direction enhances wave shape at this spot.
  summary: Poor conditions at Tsurigasaki Beach (Shidashita). Either swell direction (85°), size (2.5m), or wind (26 km/h from 17°) is unfavorable. Consider other spots or wait for better conditions.
conditions:
  swell:
    height m: 2.5
    height ft: 8.2
    direction degrees: 85
    direction cardinal: E
    period s: 12
    explanation: 2.5m (8.2ft) swell from 85° (E) at 12s period
  wind:
    speed kmh: 26
    speed mph: 16.2
    direction degrees: 17
    direction cardinal: NNE
    explanation: 26 km/h (16 mph) from 17° (NNE)
  secondary swell:
    height m: 0.8
    direction degrees: 59
    direction cardinal: ENE
    period s: 6
  windswell:
    height m: 0.9
    period s: 4
    explanation: Local wind-generated waves (choppy, short-period)

date: 2026-08-14
day index: 9
strike score:
  final score: 45
  category: Fair
  category emoji: 😐
  confidence: 0.8
  confidence explanation: Very low confidence (8-10 day forecast, conditions may change)
  breakdown:
    swell direction:
      score: 16
      out of: 25
      explanation: Moderate alignment: Swell from 90° is 20° off optimal 110°, workable but not ideal.
    swell size:
      score: 18
      out of: 25
      explanation: Marginal size: 1.7m is 0.1m from ideal 1.6m.
    swell period:
      score: 23
      out of: 25
      explanation: Good period: 11s is 92% of ideal 12s. Clean, powerful groundswell.
    wind:
      score: 7
      out of: 25
      explanation: Onshore/cross-shore: 11 km/h from 47° (NE). Destroying wave quality. Offshore range: 210°-290°.
  adjustments:
    wind history:
      adjustment: -21
      groomed: false
      morning sickness: true
      explanation: -21 points: Previous days of onshore wind left residual chop ("morning sickness"), reducing wave quality.
    windswell penalty:
      adjustment: 0
      windswell degraded: false
      explanation: Groundswell-dominant conditions (clean, long-period waves).
    secondary swell bonus:
      adjustment: 0
      explanation: No secondary swell bonus.
  summary: Surfable but not special at Tsurigasaki Beach (Shidashita). The 1.7m swell from 90° is workable, but conditions aren't ideal. Fine if you're local, but not worth a dedicated trip.
conditions:
  swell:
    height m: 1.7
    height ft: 5.6
    direction degrees: 90
    direction cardinal: E
    period s: 11
    explanation: 1.7m (5.6ft) swell from 90° (E) at 11s period
  wind:
    speed kmh: 11
    speed mph: 6.8
    direction degrees: 47
    direction cardinal: NE
    explanation: 11 km/h (7 mph) from 47° (NE)

Strike Mission
type: Organization