Surf Forecast for Praia Grande
type: Dataset
description: 10-day surf forecast with Strike Scores for Praia Grande, Sintra, Portugal
about: Praia Grande
  type: TouristAttraction
  geo: GeoCoordinates
    latitude: 38.8125
    longitude: -9.4792
  description: Praia Grande is Sintra's exposed Atlantic beach break, a consistent stretch of sand that picks up plenty of west and northwest swell. The peaks shift with the banks, offering everything from manageable walls for intermediates to hollow, punchy sections when autumn and winter groundswell arrives. Easy access from Lisbon and Cascais makes it a practical strike option, though wind exposure means timing is everything.
summary:
  best day:
    date: 2026-08-11
    score: 23
    category: Poor
    explanation: Best day in the forecast: 2026-08-11 with a score of 23/100 (Poor)
  firing days count: 0
  overall recommendation: Poor conditions overall: Average score 7/100. Look for spots with better forecasts.
forecasts:
  date: 2026-08-05
  day index: 0
  strike score:
    final score: 0
    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 317° is 22° off optimal 295°, workable but not ideal.
      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: 4
        out of: 25
        explanation: Short period: 10s is below minimum 10s. Windswell-dominated (choppy, weak waves).
      wind:
        score: 1
        out of: 25
        explanation: Onshore/cross-shore: 16 km/h from 344° (NNW). Destroying wave quality. Offshore range: 90°-135°.
    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 Praia Grande. Either swell direction (317°), size (0.9m), or wind (16 km/h from 344°) is unfavorable. Consider other spots or wait for better conditions.
  conditions:
    swell:
      height m: 0.9
      height ft: 3.0
      direction degrees: 317
      direction cardinal: NW
      period s: 10
      peak period s: 9.8
      explanation: 0.9m (3.0ft) swell from 317° (NW) at 9.8s period
    wind:
      speed kmh: 16
      speed mph: 9.9
      direction degrees: 344
      direction cardinal: NNW
      explanation: 16 km/h (10 mph) from 344° (NNW)
    secondary swell:
      height m: 0.6
      direction degrees: 276
      direction cardinal: W
      period s: 6
    windswell:
      height m: 0.3
      period s: 2
      explanation: Local wind-generated waves (choppy, short-period)
forecasts:
  date: 2026-08-06
  day index: 1
  strike score:
    final score: 0
    category: Poor
    category emoji: 💤
    confidence: 1
    confidence explanation: Very high confidence (0-1 day forecast)
    breakdown:
      swell direction:
        score: 6
        out of: 25
        explanation: Poor alignment: Swell from 336° is 41° off optimal 295°, barely within workable range 270°-320°.
      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: 8s is below minimum 10s. Windswell-dominated (choppy, weak waves).
      wind:
        score: 1
        out of: 25
        explanation: Onshore/cross-shore: 21 km/h from 352° (N). Destroying wave quality. Offshore range: 90°-135°.
    adjustments:
      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.
    summary: Poor conditions at Praia Grande. Either swell direction (336°), size (0.9m), or wind (21 km/h from 352°) is unfavorable. Consider other spots or wait for better conditions.
  conditions:
    swell:
      height m: 0.9
      height ft: 3.0
      direction degrees: 336
      direction cardinal: NNW
      period s: 8
      peak period s: 8.2
      explanation: 0.9m (3.0ft) swell from 336° (NNW) at 8.2s period
    wind:
      speed kmh: 21
      speed mph: 13.0
      direction degrees: 352
      direction cardinal: N
      explanation: 21 km/h (13 mph) from 352° (N)
    secondary swell:
      height m: 0.4
      direction degrees: 329
      direction cardinal: NNW
      period s: 6
    windswell:
      height m: 0.8
      period s: 3
      explanation: Local wind-generated waves (choppy, short-period)
forecasts:
  date: 2026-08-07
  day index: 2
  strike score:
    final score: 0
    category: Poor
    category emoji: 💤
    confidence: 0.95
    confidence explanation: High confidence (2-3 day forecast)
    breakdown:
      swell direction:
        score: 4
        out of: 25
        explanation: Poor alignment: Swell from 345° is 50° off optimal 295°, barely within workable range 270°-320°.
      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: 8s is below minimum 10s. Windswell-dominated (choppy, weak waves).
      wind:
        score: 4
        out of: 25
        explanation: Onshore/cross-shore: 13 km/h from 349° (N). Destroying wave quality. Offshore range: 90°-135°.
    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: -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 Praia Grande. Either swell direction (345°), size (0.9m), or wind (13 km/h from 349°) is unfavorable. Consider other spots or wait for better conditions.
  conditions:
    swell:
      height m: 0.9
      height ft: 3.0
      direction degrees: 345
      direction cardinal: NNW
      period s: 8
      peak period s: 8.4
      explanation: 0.9m (3.0ft) swell from 345° (NNW) at 8.4s period
    wind:
      speed kmh: 13
      speed mph: 8.1
      direction degrees: 349
      direction cardinal: N
      explanation: 13 km/h (8 mph) from 349° (N)
    secondary swell:
      height m: 0.5
      direction degrees: 314
      direction cardinal: NW
      period s: 6
provider: Strike Mission
date published: 2026-08-05T03:16:05.596Z
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)

height m: 0.4
period s: 2
explanation: Local wind-generated waves (choppy, short-period)

date: 2026-08-08
day index: 3
strike score:
  final score: 18
  category: Poor
  category emoji: 💤
  confidence: 0.92
  confidence explanation: High confidence (2-3 day forecast)
  breakdown:
    swell direction:
      score: 23
      out of: 25
      explanation: Good alignment: Swell from 292° is 3° off optimal 295°, still within prime range.
    swell size:
      score: 2
      out of: 25
      explanation: Too small: 0.8m is below minimum 1.2m. Waves will be weak/mushy.
    swell period:
      score: 4
      out of: 25
      explanation: Short period: 9s is below minimum 10s. Windswell-dominated (choppy, weak waves).
    wind:
      score: 11
      out of: 25
      explanation: Onshore/cross-shore: 9 km/h from 307° (NW). Destroying wave quality. Offshore range: 90°-135°.
  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 Praia Grande. Either swell direction (292°), size (0.8m), or wind (9 km/h from 307°) is unfavorable. Consider other spots or wait for better conditions.
conditions:
  swell:
    height m: 0.8
    height ft: 2.6
    direction degrees: 292
    direction cardinal: WNW
    period s: 9
    explanation: 0.8m (2.6ft) swell from 292° (WNW) at 9s period
  wind:
    speed kmh: 9
    speed mph: 5.6
    direction degrees: 307
    direction cardinal: NW
    explanation: 9 km/h (6 mph) from 307° (NW)
  secondary swell:
    height m: 0.4
    direction degrees: 333
    direction cardinal: NNW
    period s: 6

date: 2026-08-09
day index: 4
strike score:
  final score: 6
  category: Poor
  category emoji: 💤
  confidence: 0.89
  confidence explanation: Moderate confidence (4-5 day forecast)
  breakdown:
    swell direction:
      score: 14
      out of: 25
      explanation: Moderate alignment: Swell from 277° is 18° off optimal 295°, workable but not ideal.
    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: 8s is below minimum 10s. Windswell-dominated (choppy, weak waves).
    wind:
      score: 6
      out of: 25
      explanation: Onshore/cross-shore: 12 km/h from 342° (NNW). Destroying wave quality. Offshore range: 90°-135°.
  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: Poor conditions at Praia Grande. Either swell direction (277°), size (0.9m), or wind (12 km/h from 342°) is unfavorable. Consider other spots or wait for better conditions.
conditions:
  swell:
    height m: 0.9
    height ft: 3.0
    direction degrees: 277
    direction cardinal: W
    period s: 8
    explanation: 0.9m (3.0ft) swell from 277° (W) at 8s period
  wind:
    speed kmh: 12
    speed mph: 7.5
    direction degrees: 342
    direction cardinal: NNW
    explanation: 12 km/h (7 mph) from 342° (NNW)

date: 2026-08-10
day index: 5
strike score:
  final score: 5
  category: Poor
  category emoji: 💤
  confidence: 0.86
  confidence explanation: Moderate confidence (4-5 day forecast)
  breakdown:
    swell direction:
      score: 10
      out of: 25
      explanation: Moderate alignment: Swell from 324° is 29° off optimal 295°, workable but not ideal.
    swell size:
      score: 9
      out of: 25
      explanation: Marginal size: 1.3m is 0.5m from ideal 1.8m.
    swell period:
      score: 2
      out of: 25
      explanation: Short period: 7s is below minimum 10s. Windswell-dominated (choppy, weak waves).
    wind:
      score: 1
      out of: 25
      explanation: Onshore/cross-shore: 17 km/h from 336° (NNW). Destroying wave quality. Offshore range: 90°-135°.
  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 Praia Grande. Either swell direction (324°), size (1.3m), or wind (17 km/h from 336°) is unfavorable. Consider other spots or wait for better conditions.
conditions:
  swell:
    height m: 1.3
    height ft: 4.3
    direction degrees: 324
    direction cardinal: NW
    period s: 7
    explanation: 1.3m (4.3ft) swell from 324° (NW) at 7s period
  wind:
    speed kmh: 17
    speed mph: 10.6
    direction degrees: 336
    direction cardinal: NNW
    explanation: 17 km/h (11 mph) from 336° (NNW)
  windswell:
    height m: 0.4
    period s: 2
    explanation: Local wind-generated waves (choppy, short-period)

date: 2026-08-11
day index: 6
strike score:
  final score: 23
  category: Poor
  category emoji: 💤
  confidence: 0.83
  confidence explanation: Low confidence (6-7 day forecast)
  breakdown:
    swell direction:
      score: 8
      out of: 25
      explanation: Poor alignment: Swell from 331° is 36° off optimal 295°, barely within workable range 270°-320°.
    swell size:
      score: 9
      out of: 25
      explanation: Marginal size: 1.3m is 0.5m from ideal 1.8m.
    swell period:
      score: 8
      out of: 25
      explanation: Moderate period: 11s meets minimum 10s but below ideal 14s. Some groundswell energy present.
    wind:
      score: 8
      out of: 25
      explanation: Onshore/cross-shore: 11 km/h from 340° (NNW). Destroying wave quality. Offshore range: 90°-135°.
  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 Praia Grande. Either swell direction (331°), size (1.3m), or wind (11 km/h from 340°) is unfavorable. Consider other spots or wait for better conditions.
conditions:
  swell:
    height m: 1.3
    height ft: 4.3
    direction degrees: 331
    direction cardinal: NNW
    period s: 11
    explanation: 1.3m (4.3ft) swell from 331° (NNW) at 11s period
  wind:
    speed kmh: 11
    speed mph: 6.8
    direction degrees: 340
    direction cardinal: NNW
    explanation: 11 km/h (7 mph) from 340° (NNW)
  secondary swell:
    height m: 0.4
    direction degrees: 307
    direction cardinal: NW
    period s: 10
  windswell:
    height m: 0.4
    period s: 3
    explanation: Local wind-generated waves (choppy, short-period)

date: 2026-08-12
day index: 7
strike score:
  final score: 11
  category: Poor
  category emoji: 💤
  confidence: 0.8
  confidence explanation: Low confidence (6-7 day forecast)
  breakdown:
    swell direction:
      score: 23
      out of: 25
      explanation: Good alignment: Swell from 298° is 3° off optimal 295°, still within prime range.
    swell size:
      score: 8
      out of: 25
      explanation: Marginal size: 1.2m is 0.6m from ideal 1.8m.
    swell period:
      score: 6
      out of: 25
      explanation: Moderate period: 10s meets minimum 10s but below ideal 14s. Some groundswell energy present.
    wind:
      score: 1
      out of: 25
      explanation: Onshore/cross-shore: 20 km/h from 342° (NNW). Destroying wave quality. Offshore range: 90°-135°.
  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 Praia Grande. Either swell direction (298°), size (1.2m), or wind (20 km/h from 342°) is unfavorable. Consider other spots or wait for better conditions.
conditions:
  swell:
    height m: 1.2
    height ft: 3.9
    direction degrees: 298
    direction cardinal: WNW
    period s: 10
    explanation: 1.2m (3.9ft) swell from 298° (WNW) at 10s period
  wind:
    speed kmh: 20
    speed mph: 12.4
    direction degrees: 342
    direction cardinal: NNW
    explanation: 20 km/h (12 mph) from 342° (NNW)
  secondary swell:
    height m: 0.7
    direction degrees: 328
    direction cardinal: NNW
    period s: 8
  windswell:
    height m: 0.3
    period s: 2
    explanation: Local wind-generated waves (choppy, short-period)

date: 2026-08-13
day index: 8
strike score:
  final score: 5
  category: Poor
  category emoji: 💤
  confidence: 0.8
  confidence explanation: Very low confidence (8-10 day forecast, conditions may change)
  breakdown:
    swell direction:
      score: 19
      out of: 25
      explanation: Moderate alignment: Swell from 304° is 9° off optimal 295°, 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: 6
      out of: 25
      explanation: Moderate period: 10s meets minimum 10s but below ideal 14s. Some groundswell energy present.
    wind:
      score: 0
      out of: 25
      explanation: Onshore/cross-shore: 28 km/h from 350° (N). Destroying wave quality. Offshore range: 90°-135°.
  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 Praia Grande. Either swell direction (304°), size (1.1m), or wind (28 km/h from 350°) is unfavorable. Consider other spots or wait for better conditions.
conditions:
  swell:
    height m: 1.1
    height ft: 3.6
    direction degrees: 304
    direction cardinal: NW
    period s: 10
    explanation: 1.1m (3.6ft) swell from 304° (NW) at 10s period
  wind:
    speed kmh: 28
    speed mph: 17.4
    direction degrees: 350
    direction cardinal: N
    explanation: 28 km/h (17 mph) from 350° (N)
  secondary swell:
    height m: 0.6
    direction degrees: 309
    direction cardinal: NW
    period s: 9
  windswell:
    height m: 0.7
    period s: 3
    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: 17
      out of: 25
      explanation: Moderate alignment: Swell from 283° is 12° off optimal 295°, workable but not ideal.
    swell size:
      score: 2
      out of: 25
      explanation: Too small: 0.8m is below minimum 1.2m. Waves will be weak/mushy.
    swell period:
      score: 4
      out of: 25
      explanation: Short period: 9s is below minimum 10s. Windswell-dominated (choppy, weak waves).
    wind:
      score: 0
      out of: 25
      explanation: Onshore/cross-shore: 27 km/h from 350° (N). Destroying wave quality. Offshore range: 90°-135°.
  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 Praia Grande. Either swell direction (283°), size (0.8m), or wind (27 km/h from 350°) is unfavorable. Consider other spots or wait for better conditions.
conditions:
  swell:
    height m: 0.8
    height ft: 2.6
    direction degrees: 283
    direction cardinal: WNW
    period s: 9
    explanation: 0.8m (2.6ft) swell from 283° (WNW) at 9s period
  wind:
    speed kmh: 27
    speed mph: 16.8
    direction degrees: 350
    direction cardinal: N
    explanation: 27 km/h (17 mph) from 350° (N)

Strike Mission
type: Organization