Surf Forecast for Porthleven Reef
type: Dataset
description: 10-day surf forecast with Strike Scores for Porthleven Reef, South Cornwall, UK
about: Porthleven Reef
  type: TouristAttraction
  geo: GeoCoordinates
    latitude: 50.0833
    longitude: -5.3167
  description: Porthleven is Cornwall's heavy-water arena--a powerful reef break that detonates beside the harbour wall when sizeable SW groundswells wrap into Mount's Bay. The wave is an A-frame but the right is the prize.
summary:
  best day:
    date: 2026-08-06
    score: 35
    category: Poor
    explanation: Best day in the forecast: 2026-08-06 with a score of 35/100 (Poor)
  firing days count: 0
  overall recommendation: Poor conditions overall: Average score 10/100. Look for spots with better forecasts.
forecasts:
  date: 2026-08-05
  day index: 0
  strike score:
    final score: 7
    category: Poor
    category emoji: 💤
    confidence: 1
    confidence explanation: Very high confidence (0-1 day forecast)
    breakdown:
      swell direction:
        score: 12
        out of: 25
        explanation: Moderate alignment: Swell from 247° is 22° off optimal 225°, workable but not ideal.
      swell size:
        score: 5
        out of: 25
        explanation: Too small: 1.1m is below minimum 1.2m. Waves will be weak/mushy.
      swell period:
        score: 9
        out of: 25
        explanation: Moderate period: 11s meets minimum 10s but below ideal 14s. Some groundswell energy present.
      wind:
        score: 1
        out of: 25
        explanation: Onshore/cross-shore: 19 km/h from 292° (WNW). Destroying wave quality. Offshore range: 315°-70°.
    adjustments:
      wind history:
        adjustment: 0
        groomed: false
        morning sickness: false
        explanation: No significant wind history adjustment.
      windswell penalty:
        adjustment: -3
        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 Porthleven Reef. Either swell direction (247°), size (1.1m), or wind (19 km/h from 292°) is unfavorable. Consider other spots or wait for better conditions.
  conditions:
    swell:
      height m: 1.1
      height ft: 3.6
      direction degrees: 247
      direction cardinal: WSW
      period s: 11
      peak period s: 11.2
      explanation: 1.1m (3.6ft) swell from 247° (WSW) at 11.2s period
    wind:
      speed kmh: 19
      speed mph: 11.8
      direction degrees: 292
      direction cardinal: WNW
      explanation: 19 km/h (12 mph) from 292° (WNW)
    secondary swell:
      height m: 0.5
      direction degrees: 264
      direction cardinal: W
      period s: 7
    windswell:
      height m: 0.7
      period s: 3
      explanation: Local wind-generated waves (choppy, short-period)
forecasts:
  date: 2026-08-06
  day index: 1
  strike score:
    final score: 35
    category: Poor
    category emoji: 💤
    confidence: 1
    confidence explanation: Very high confidence (0-1 day forecast)
    breakdown:
      swell direction:
        score: 5
        out of: 25
        explanation: Poor alignment: Swell from 272° is 47° off optimal 225°, barely within workable range 200°-260°.
      swell size:
        score: 3
        out of: 25
        explanation: Too small: 0.9m is below minimum 1.2m. Waves will be weak/mushy.
      swell period:
        score: 24
        out of: 25
        explanation: Perfect period: 14s is at or above ideal 14s. Long-period groundswell with maximum power.
      wind:
        score: 7
        out of: 25
        explanation: Onshore/cross-shore: 13 km/h from 272° (W). Destroying wave quality. Offshore range: 315°-70°.
    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: Poor conditions at Porthleven Reef. Either swell direction (272°), size (0.9m), or wind (13 km/h from 272°) is unfavorable. Consider other spots or wait for better conditions.
  conditions:
    swell:
      height m: 0.9
      height ft: 3.0
      direction degrees: 272
      direction cardinal: W
      period s: 14
      peak period s: 13.5
      explanation: 0.9m (3.0ft) swell from 272° (W) at 13.5s period
    wind:
      speed kmh: 13
      speed mph: 8.1
      direction degrees: 272
      direction cardinal: W
      explanation: 13 km/h (8 mph) from 272° (W)
forecasts:
  date: 2026-08-07
  day index: 2
  strike score:
    final score: 15
    category: Poor
    category emoji: 💤
    confidence: 0.95
    confidence explanation: High confidence (2-3 day forecast)
    breakdown:
      swell direction:
        score: 3
        out of: 25
        explanation: Poor alignment: Swell from 277° is 52° off optimal 225°, barely within workable range 200°-260°.
      swell size:
        score: 1
        out of: 25
        explanation: Too small: 0.4m is below minimum 1.2m. Waves will be weak/mushy.
      swell period:
        score: 17
        out of: 25
        explanation: Moderate period: 12s meets minimum 10s but below ideal 14s. Some groundswell energy present.
      wind:
        score: 11
        out of: 25
        explanation: Onshore/cross-shore: 9 km/h from 226° (SW). Destroying wave quality. Offshore range: 315°-70°.
    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: Poor conditions at Porthleven Reef. Either swell direction (277°), size (0.4m), or wind (9 km/h from 226°) is unfavorable. Consider other spots or wait for better conditions.
  conditions:
    swell:
      height m: 0.4
      height ft: 1.3
      direction degrees: 277
      direction cardinal: W
      period s: 12
      peak period s: 12.3
      explanation: 0.4m (1.3ft) swell from 277° (W) at 12.3s period
    wind:
      speed kmh: 9
      speed mph: 5.6
      direction degrees: 226
      direction cardinal: SW
      explanation: 9 km/h (6 mph) from 226° (SW)
forecasts:
  date: 2026-08-08
  day index: 3
  strike score:
    final score: 0
    category: Poor
    category emoji: 💤
    confidence: 0.92
    confidence explanation: High confidence (2-3 day forecast)
    breakdown:
      swell direction:
        score: 7
        out of: 25
        explanation: Poor alignment: Swell from 263° is 38° off optimal 225°, barely within workable range 200°-260°.
    summary: Poor conditions at Porthleven Reef. Either swell direction (263°), size (0.3m), or wind (16 km/h from 133°) is unfavorable. Consider other spots or wait for better conditions.
provider: Strike Mission
date published: 2026-08-05T03:15:53.592Z
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)

score: 1
out of: 25
explanation: Too small: 0.3m is below minimum 1.2m. Waves will be weak/mushy.

score: 2
out of: 25
explanation: Short period: 7s is below minimum 10s. Windswell-dominated (choppy, weak waves).

score: 1
out of: 25
explanation: Onshore/cross-shore: 16 km/h from 133° (SE). Destroying wave quality. Offshore range: 315°-70°.

wind history:
  adjustment: 0
  groomed: false
  morning sickness: false
  explanation: No significant wind history adjustment.
windswell penalty:
  adjustment: -5
  windswell degraded: true
  explanation: -5 points: Short-period windswell is present, creating choppy, disorganized conditions.
secondary swell bonus:
  adjustment: 0
  explanation: No secondary swell bonus.

swell:
  height m: 0.3
  height ft: 1.0
  direction degrees: 263
  direction cardinal: W
  period s: 7
  explanation: 0.3m (1.0ft) swell from 263° (W) at 7s period
wind:
  speed kmh: 16
  speed mph: 9.9
  direction degrees: 133
  direction cardinal: SE
  explanation: 16 km/h (10 mph) from 133° (SE)
windswell:
  height m: 0.3
  period s: 2
  explanation: Local wind-generated waves (choppy, short-period)

date: 2026-08-09
day index: 4
strike score:
  final score: 21
  category: Poor
  category emoji: 💤
  confidence: 0.89
  confidence explanation: Moderate confidence (4-5 day forecast)
  breakdown:
    swell direction:
      score: 17
      out of: 25
      explanation: Moderate alignment: Swell from 237° is 12° off optimal 225°, workable but not ideal.
    swell size:
      score: 2
      out of: 25
      explanation: Too small: 0.6m is below minimum 1.2m. Waves will be weak/mushy.
    swell period:
      score: 0
      out of: 25
      explanation: Short period: 5s is below minimum 10s. Windswell-dominated (choppy, weak waves).
    wind:
      score: 24
      out of: 25
      explanation: Moderate offshore: 14 km/h from 343° (NNW). Still grooming but noticeable wind.
  adjustments:
    wind history:
      adjustment: 0
      groomed: false
      morning sickness: false
      explanation: No significant wind history adjustment.
    windswell penalty:
      adjustment: -7
      windswell degraded: true
      explanation: -7 points: Short-period windswell is present, creating choppy, disorganized conditions.
    secondary swell bonus:
      adjustment: 0
      explanation: No secondary swell bonus.
  summary: Poor conditions at Porthleven Reef. Either swell direction (237°), size (0.6m), or wind (14 km/h from 343°) is unfavorable. Consider other spots or wait for better conditions.
conditions:
  swell:
    height m: 0.6
    height ft: 2.0
    direction degrees: 237
    direction cardinal: WSW
    period s: 5
    explanation: 0.6m (2.0ft) swell from 237° (WSW) at 5s period
  wind:
    speed kmh: 14
    speed mph: 8.7
    direction degrees: 343
    direction cardinal: NNW
    explanation: 14 km/h (9 mph) from 343° (NNW)
  windswell:
    height m: 0.8
    period s: 3
    explanation: Local wind-generated waves (choppy, short-period)

date: 2026-08-10
day index: 5
strike score:
  final score: 18
  category: Poor
  category emoji: 💤
  confidence: 0.86
  confidence explanation: Moderate confidence (4-5 day forecast)
  breakdown:
    swell direction:
      score: 6
      out of: 25
      explanation: Poor alignment: Swell from 267° is 42° off optimal 225°, barely within workable range 200°-260°.
    swell size:
      score: 3
      out of: 25
      explanation: Too small: 0.9m is below minimum 1.2m. Waves will be weak/mushy.
    swell period:
      score: 2
      out of: 25
      explanation: Short period: 7s is below minimum 10s. Windswell-dominated (choppy, weak waves).
    wind:
      score: 20
      out of: 25
      explanation: Moderate offshore: 12 km/h from 333° (NNW). Still grooming but noticeable wind.
  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: Poor conditions at Porthleven Reef. Either swell direction (267°), size (0.9m), or wind (12 km/h from 333°) is unfavorable. Consider other spots or wait for better conditions.
conditions:
  swell:
    height m: 0.9
    height ft: 3.0
    direction degrees: 267
    direction cardinal: W
    period s: 7
    explanation: 0.9m (3.0ft) swell from 267° (W) at 7s period
  wind:
    speed kmh: 12
    speed mph: 7.5
    direction degrees: 333
    direction cardinal: NNW
    explanation: 12 km/h (7 mph) from 333° (NNW)
  secondary swell:
    height m: 0.5
    direction degrees: 281
    direction cardinal: W
    period s: 7

date: 2026-08-11
day index: 6
strike score:
  final score: 0
  category: Poor
  category emoji: 💤
  confidence: 0.83
  confidence explanation: Low confidence (6-7 day forecast)
  breakdown:
    swell direction:
      score: 23
      out of: 25
      explanation: Good alignment: Swell from 228° is 3° off optimal 225°, still within prime range.
    swell size:
      score: 1
      out of: 25
      explanation: Too small: 0.5m is below minimum 1.2m. Waves will be weak/mushy.
    swell period:
      score: 0
      out of: 25
      explanation: Short period: 5s is below minimum 10s. Windswell-dominated (choppy, weak waves).
    wind:
      score: 1
      out of: 25
      explanation: Onshore/cross-shore: 15 km/h from 127° (SE). Destroying wave quality. Offshore range: 315°-70°.
  adjustments:
    wind history:
      adjustment: 0
      groomed: false
      morning sickness: false
      explanation: No significant wind history adjustment.
    windswell penalty:
      adjustment: -3
      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 Porthleven Reef. Either swell direction (228°), size (0.5m), or wind (15 km/h from 127°) is unfavorable. Consider other spots or wait for better conditions.
conditions:
  swell:
    height m: 0.5
    height ft: 1.6
    direction degrees: 228
    direction cardinal: SW
    period s: 5
    explanation: 0.5m (1.6ft) swell from 228° (SW) at 5s period
  wind:
    speed kmh: 15
    speed mph: 9.3
    direction degrees: 127
    direction cardinal: SE
    explanation: 15 km/h (9 mph) from 127° (SE)
  windswell:
    height m: 0.3
    period s: 2
    explanation: Local wind-generated waves (choppy, short-period)

date: 2026-08-12
day index: 7
strike score:
  final score: 0
  category: Poor
  category emoji: 💤
  confidence: 0.8
  confidence explanation: Low confidence (6-7 day forecast)
  breakdown:
    swell direction:
      score: 9
      out of: 25
      explanation: Poor alignment: Swell from 256° is 31° off optimal 225°, barely within workable range 200°-260°.
    swell size:
      score: 9
      out of: 25
      explanation: Marginal size: 1.3m is 1.1m from ideal 2.4m.
    swell period:
      score: 2
      out of: 25
      explanation: Short period: 8s is below minimum 10s. Windswell-dominated (choppy, weak waves).
    wind:
      score: 1
      out of: 25
      explanation: Onshore/cross-shore: 22 km/h from 241° (WSW). Destroying wave quality. Offshore range: 315°-70°.
  adjustments:
    wind history:
      adjustment: 0
      groomed: false
      morning sickness: false
      explanation: No significant wind history adjustment.
    windswell penalty:
      adjustment: -3
      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 Porthleven Reef. Either swell direction (256°), size (1.3m), or wind (22 km/h from 241°) is unfavorable. Consider other spots or wait for better conditions.
conditions:
  swell:
    height m: 1.3
    height ft: 4.3
    direction degrees: 256
    direction cardinal: WSW
    period s: 8
    explanation: 1.3m (4.3ft) swell from 256° (WSW) at 8s period
  wind:
    speed kmh: 22
    speed mph: 13.7
    direction degrees: 241
    direction cardinal: WSW
    explanation: 22 km/h (14 mph) from 241° (WSW)
  secondary swell:
    height m: 0.4
    direction degrees: 248
    direction cardinal: WSW
    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: 3
  category: Poor
  category emoji: 💤
  confidence: 0.8
  confidence explanation: Very low confidence (8-10 day forecast, conditions may change)
  breakdown:
    swell direction:
      score: 9
      out of: 25
      explanation: Poor alignment: Swell from 257° is 32° off optimal 225°, barely within workable range 200°-260°.
    swell size:
      score: 8
      out of: 25
      explanation: Marginal size: 1.2m is 1.2m from ideal 2.4m.
    swell period:
      score: 4
      out of: 25
      explanation: Short period: 9s is below minimum 10s. Windswell-dominated (choppy, weak waves).
    wind:
      score: 5
      out of: 25
      explanation: Onshore/cross-shore: 13 km/h from 263° (W). Destroying wave quality. Offshore range: 315°-70°.
  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: 0
      explanation: No secondary swell bonus.
  summary: Poor conditions at Porthleven Reef. Either swell direction (257°), size (1.2m), or wind (13 km/h from 263°) is unfavorable. Consider other spots or wait for better conditions.
conditions:
  swell:
    height m: 1.2
    height ft: 3.9
    direction degrees: 257
    direction cardinal: WSW
    period s: 9
    explanation: 1.2m (3.9ft) swell from 257° (WSW) at 9s period
  wind:
    speed kmh: 13
    speed mph: 8.1
    direction degrees: 263
    direction cardinal: W
    explanation: 13 km/h (8 mph) from 263° (W)
  secondary swell:
    height m: 0.8
    direction degrees: 273
    direction cardinal: W
    period s: 8
  windswell:
    height m: 0.3
    period s: 2
    explanation: Local wind-generated waves (choppy, short-period)

date: 2026-08-14
day index: 9
strike score:
  final score: 0
  category: Poor
  category emoji: 💤
  confidence: 0.8
  confidence explanation: Very low confidence (8-10 day forecast, conditions may change)
  breakdown:
    swell direction:
      score: 0
      out of: 25
      explanation: No alignment: Swell from 0° is outside workable range 200°-260°. Wrong swell direction for this spot.
    swell size:
      score: 0
      out of: 25
      explanation: Too small: 0.0m is below minimum 1.2m. Waves will be weak/mushy.
    swell period:
      score: 8
      out of: 25
      explanation: Moderate period: 11s meets minimum 10s but below ideal 14s. Some groundswell energy present.
    wind:
      score: 1
      out of: 25
      explanation: Onshore/cross-shore: 21 km/h from 250° (WSW). Destroying wave quality. Offshore range: 315°-70°.
  adjustments:
    wind history:
      adjustment: -7
      groomed: false
      morning sickness: true
      explanation: -7 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 Porthleven Reef. Either swell direction (0°), size (0.0m), or wind (21 km/h from 250°) is unfavorable. Consider other spots or wait for better conditions.
conditions:
  swell:
    height m: 0
    height ft: 0.0
    direction degrees: 0
    direction cardinal: N
    period s: 11
    explanation: 0.0m (0.0ft) swell from 0° (N) at 11s period
  wind:
    speed kmh: 21
    speed mph: 13.0
    direction degrees: 250
    direction cardinal: WSW
    explanation: 21 km/h (13 mph) from 250° (WSW)

Strike Mission
type: Organization