Surf Forecast for Prainha
type: Dataset
description: 10-day surf forecast with Strike Scores for Prainha, Rio de Janeiro, RJ, Brazil
about: Prainha
  type: TouristAttraction
  geo: GeoCoordinates
    latitude: -23.0417
    longitude: -43.5083
  description: Prainha is Rio de Janeiro's most consistent quality surf spot, a crescent-shaped beach nestled in the Atlantic Forest reserve west of the city. The wave breaks over a mix of sand and rock, producing powerful peaks that can handle solid S and SW swells without closing out. The setting is stunning - dense green jungle tumbles down to the beach, making it feel a world away from the urban chaos just 30 minutes back toward the city. The local crew is experienced and the vibe is more serious than Rio's tourist beaches.
summary:
  best day:
    date: 2026-08-09
    score: 81
    category: Firing
    explanation: Best day in the forecast: 2026-08-09 with a score of 81/100 (Firing)
  firing days count: 1
  firing days:
    date: 2026-08-09
    score: 81
  overall recommendation: Moderate recommendation: Prainha has 1 Firing day(s) and 1 Good day(s). Worth considering.
forecasts:
  date: 2026-08-05
  day index: 0
  strike score:
    final score: 52
    category: Fair
    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 180° is 22° off optimal 202°, workable but not ideal.
      swell size:
        score: 10
        out of: 25
        explanation: Marginal size: 1.2m is 0.8m from ideal 1.9m.
      swell period:
        score: 23
        out of: 25
        explanation: Good period: 13s is 93% of ideal 14s. Clean, powerful groundswell.
      wind:
        score: 11
        out of: 25
        explanation: Onshore/cross-shore: 11 km/h from 23° (NNE). Destroying wave quality. Offshore range: 270°-360°.
    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 Prainha. The 1.2m swell from 180° is workable, but conditions aren't ideal. Fine if you're local, but not worth a dedicated trip.
  conditions:
    swell:
      height m: 1.2
      height ft: 3.9
      direction degrees: 180
      direction cardinal: S
      period s: 13
      explanation: 1.2m (3.9ft) swell from 180° (S) at 13s period
    wind:
      speed kmh: 11
      speed mph: 6.8
      direction degrees: 23
      direction cardinal: NNE
      explanation: 11 km/h (7 mph) from 23° (NNE)
    secondary swell:
      height m: 0.6
      direction degrees: 115
      direction cardinal: ESE
      period s: 6
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: 0
        out of: 25
        explanation: No alignment: Swell from 95° is outside workable range 157°-247°. Wrong swell direction for this spot.
      swell size:
        score: 9
        out of: 25
        explanation: Marginal size: 1.1m is 0.8m from ideal 1.9m.
      swell period:
        score: 4
        out of: 25
        explanation: Short period: 9s is below minimum 10s. Windswell-dominated (choppy, weak waves).
      wind:
        score: 1
        out of: 25
        explanation: Onshore/cross-shore: 15 km/h from 4° (N). Destroying wave quality. Offshore range: 270°-360°.
    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 Prainha. Either swell direction (95°), size (1.1m), or wind (15 km/h from 4°) is unfavorable. Consider other spots or wait for better conditions.
  conditions:
    swell:
      height m: 1.1
      height ft: 3.6
      direction degrees: 95
      direction cardinal: E
      period s: 9
      explanation: 1.1m (3.6ft) swell from 95° (E) at 9s period
    wind:
      speed kmh: 15
      speed mph: 9.3
      direction degrees: 4
      direction cardinal: N
      explanation: 15 km/h (9 mph) from 4° (N)
    secondary swell:
      height m: 0.6
      direction degrees: 164
      direction cardinal: SSE
      period s: 8
    windswell:
      height m: 0.3
      period s: 2
      explanation: Local wind-generated waves (choppy, short-period)
forecasts:
  date: 2026-08-07
  day index: 2
  strike score:
    final score: 9
    category: Poor
    category emoji: 💤
    confidence: 0.95
    confidence explanation: High confidence (2-3 day forecast)
    breakdown:
      swell direction:
        score: 0
        out of: 25
        explanation: No alignment: Swell from 89° is outside workable range 157°-247°. Wrong swell direction for this spot.
      swell size:
        score: 8
        out of: 25
        explanation: Marginal size: 0.9m is 1.0m from ideal 1.9m.
      swell period:
        score: 2
        out of: 25
        explanation: Short period: 8s is below minimum 10s. Windswell-dominated (choppy, weak waves).
      wind:
        score: 23
        out of: 25
        explanation: Moderate offshore: 18 km/h from 325° (NW). 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 Prainha. Either swell direction (89°), size (0.9m), or wind (18 km/h from 325°) is unfavorable. Consider other spots or wait for better conditions.
  conditions:
    swell:
      height m: 0.9
      height ft: 3.0
      direction degrees: 89
      direction cardinal: E
      period s: 8
      explanation: 0.9m (3.0ft) swell from 89° (E) at 8s period
    wind:
      speed kmh: 18
      speed mph: 11.2
      direction degrees: 325
      direction cardinal: NW
      explanation: 18 km/h (11 mph) from 325° (NW)
    secondary swell:
      height m: 0.5
      direction degrees: 169
      direction cardinal: S
      period s: 8
    windswell:
      height m: 0.3
      period s: 2
      explanation: Local wind-generated waves (choppy, short-period)
provider: Strike Mission
date published: 2026-08-05T03:15:49.397Z
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)

date: 2026-08-08
day index: 3
strike score:
  final score: 41
  category: Poor
  category emoji: 💤
  confidence: 0.92
  confidence explanation: High confidence (2-3 day forecast)
  breakdown:
    swell direction:
      score: 21
      out of: 25
      explanation: Good alignment: Swell from 197° is 5° off optimal 202°, still within prime range.
    swell size:
      score: 13
      out of: 25
      explanation: Marginal size: 1.6m is 0.3m from ideal 1.9m.
    swell period:
      score: 8
      out of: 25
      explanation: Moderate period: 11s meets minimum 10s but below ideal 14s. Some groundswell energy present.
    wind:
      score: 4
      out of: 25
      explanation: Onshore/cross-shore: 13 km/h from 88° (E). Destroying wave quality. Offshore range: 270°-360°.
  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 Prainha. Either swell direction (197°), size (1.6m), or wind (13 km/h from 88°) is unfavorable. Consider other spots or wait for better conditions.
conditions:
  swell:
    height m: 1.6
    height ft: 5.2
    direction degrees: 197
    direction cardinal: SSW
    period s: 11
    explanation: 1.6m (5.2ft) swell from 197° (SSW) at 11s period
  wind:
    speed kmh: 13
    speed mph: 8.1
    direction degrees: 88
    direction cardinal: E
    explanation: 13 km/h (8 mph) from 88° (E)
  secondary swell:
    height m: 0.4
    direction degrees: 148
    direction cardinal: SSE
    period s: 7

date: 2026-08-09
day index: 4
strike score:
  final score: 81
  category: Firing
  category emoji: 🔥
  confidence: 0.89
  confidence explanation: Moderate confidence (4-5 day forecast)
  breakdown:
    swell direction:
      score: 19
      out of: 25
      explanation: Moderate alignment: Swell from 194° is 8° off optimal 202°, workable but not ideal.
    swell size:
      score: 21
      out of: 25
      explanation: Good size: 2.2m is within 15% of ideal 1.9m.
    swell period:
      score: 25
      out of: 25
      explanation: Perfect period: 14s is at or above ideal 14s. Long-period groundswell with maximum power.
    wind:
      score: 21
      out of: 25
      explanation: Strong offshore: 21 km/h from 303° (WNW). Grooming but may make paddling difficult.
  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 Prainha. The 2.2m swell from 194° aligns well with the spot, and offshore winds are grooming the face. Worth planning a trip around this.
conditions:
  swell:
    height m: 2.2
    height ft: 7.2
    direction degrees: 194
    direction cardinal: SSW
    period s: 14
    explanation: 2.2m (7.2ft) swell from 194° (SSW) at 14s period
  wind:
    speed kmh: 21
    speed mph: 13.0
    direction degrees: 303
    direction cardinal: WNW
    explanation: 21 km/h (13 mph) from 303° (WNW)
  secondary swell:
    height m: 0.6
    direction degrees: 110
    direction cardinal: ESE
    period s: 7
  windswell:
    height m: 0.5
    period s: 3
    explanation: Local wind-generated waves (choppy, short-period)

date: 2026-08-10
day index: 5
strike score:
  final score: 48
  category: Fair
  category emoji: 😐
  confidence: 0.86
  confidence explanation: Moderate confidence (4-5 day forecast)
  breakdown:
    swell direction:
      score: 13
      out of: 25
      explanation: Moderate alignment: Swell from 183° is 19° off optimal 202°, workable but not ideal.
    swell size:
      score: 21
      out of: 25
      explanation: Good size: 2.2m is within 15% of ideal 1.9m.
    swell period:
      score: 14
      out of: 25
      explanation: Moderate period: 12s meets minimum 10s but below ideal 14s. Some groundswell energy present.
    wind:
      score: 5
      out of: 25
      explanation: Onshore/cross-shore: 12 km/h from 123° (ESE). Destroying wave quality. Offshore range: 270°-360°.
  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 Prainha. The 2.2m swell from 183° 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: 183
    direction cardinal: S
    period s: 12
    explanation: 2.2m (7.2ft) swell from 183° (S) at 12s period
  wind:
    speed kmh: 12
    speed mph: 7.5
    direction degrees: 123
    direction cardinal: ESE
    explanation: 12 km/h (7 mph) from 123° (ESE)
  secondary swell:
    height m: 0.7
    direction degrees: 175
    direction cardinal: S
    period s: 11

date: 2026-08-11
day index: 6
strike score:
  final score: 35
  category: Poor
  category emoji: 💤
  confidence: 0.83
  confidence explanation: Low confidence (6-7 day forecast)
  breakdown:
    swell direction:
      score: 17
      out of: 25
      explanation: Moderate alignment: Swell from 190° is 12° off optimal 202°, workable but not ideal.
    swell size:
      score: 13
      out of: 25
      explanation: Too big: 3.2m exceeds maximum 3.0m. Risk of closeouts.
    swell period:
      score: 14
      out of: 25
      explanation: Moderate period: 12s 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 190° (S). Destroying wave quality. Offshore range: 270°-360°.
  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 Prainha. Either swell direction (190°), size (3.2m), or wind (20 km/h from 190°) is unfavorable. Consider other spots or wait for better conditions.
conditions:
  swell:
    height m: 3.2
    height ft: 10.5
    direction degrees: 190
    direction cardinal: S
    period s: 12
    explanation: 3.2m (10.5ft) swell from 190° (S) at 12s period
  wind:
    speed kmh: 20
    speed mph: 12.4
    direction degrees: 190
    direction cardinal: S
    explanation: 20 km/h (12 mph) from 190° (S)
  windswell:
    height m: 0.8
    period s: 4
    explanation: Local wind-generated waves (choppy, short-period)

date: 2026-08-12
day index: 7
strike score:
  final score: 54
  category: Fair
  category emoji: 😐
  confidence: 0.8
  confidence explanation: Low confidence (6-7 day forecast)
  breakdown:
    swell direction:
      score: 17
      out of: 25
      explanation: Moderate alignment: Swell from 191° is 11° off optimal 202°, workable but not ideal.
    swell size:
      score: 19
      out of: 25
      explanation: Marginal size: 2.7m is 0.8m from ideal 1.9m.
    swell period:
      score: 8
      out of: 25
      explanation: Moderate period: 11s meets minimum 10s but below ideal 14s. Some groundswell energy present.
    wind:
      score: 13
      out of: 25
      explanation: Onshore/cross-shore: 8 km/h from 145° (SE). Destroying wave quality. Offshore range: 270°-360°.
  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 Prainha. The 2.7m swell from 191° is workable, but conditions aren't ideal. Fine if you're local, but not worth a dedicated trip.
conditions:
  swell:
    height m: 2.7
    height ft: 8.9
    direction degrees: 191
    direction cardinal: S
    period s: 11
    explanation: 2.7m (8.9ft) swell from 191° (S) at 11s period
  wind:
    speed kmh: 8
    speed mph: 5.0
    direction degrees: 145
    direction cardinal: SE
    explanation: 8 km/h (5 mph) from 145° (SE)

date: 2026-08-13
day index: 8
strike score:
  final score: 64
  category: Fair
  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 185° is 17° off optimal 202°, workable but not ideal.
    swell size:
      score: 24
      out of: 25
      explanation: Perfect size: 2.4m is at the sweet spot (ideal: 1.9m).
    swell period:
      score: 23
      out of: 25
      explanation: Good period: 13s is 93% of ideal 14s. Clean, powerful groundswell.
    wind:
      score: 8
      out of: 25
      explanation: Onshore/cross-shore: 11 km/h from 76° (ENE). Destroying wave quality. Offshore range: 270°-360°.
  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 Prainha. The 2.4m swell from 185° is workable, but conditions aren't ideal. Fine if you're local, but not worth a dedicated trip.
conditions:
  swell:
    height m: 2.4
    height ft: 7.9
    direction degrees: 185
    direction cardinal: S
    period s: 13
    explanation: 2.4m (7.9ft) swell from 185° (S) at 13s period
  wind:
    speed kmh: 11
    speed mph: 6.8
    direction degrees: 76
    direction cardinal: ENE
    explanation: 11 km/h (7 mph) from 76° (ENE)
  secondary swell:
    height m: 0.5
    direction degrees: 124
    direction cardinal: SE
    period s: 9

date: 2026-08-14
day index: 9
strike score:
  final score: 65
  category: Good
  category emoji: ✅
  confidence: 0.8
  confidence explanation: Very low confidence (8-10 day forecast, conditions may change)
  breakdown:
    swell direction:
      score: 12
      out of: 25
      explanation: Moderate alignment: Swell from 180° is 22° off optimal 202°, workable but not ideal.
    swell size:
      score: 23
      out of: 25
      explanation: Good size: 2.3m is within 15% of ideal 1.9m.
    swell period:
      score: 25
      out of: 25
      explanation: Perfect period: 14s is at or above ideal 14s. Long-period groundswell with maximum power.
    wind:
      score: 10
      out of: 25
      explanation: Onshore/cross-shore: 10 km/h from 82° (E). Destroying wave quality. Offshore range: 270°-360°.
  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 Prainha. 2.3m swell from 180° with manageable wind. Solid session guaranteed.
conditions:
  swell:
    height m: 2.3
    height ft: 7.5
    direction degrees: 180
    direction cardinal: S
    period s: 14
    explanation: 2.3m (7.5ft) swell from 180° (S) at 14s period
  wind:
    speed kmh: 10
    speed mph: 6.2
    direction degrees: 82
    direction cardinal: E
    explanation: 10 km/h (6 mph) from 82° (E)

Strike Mission
type: Organization