Surf Forecast for Pero Lefts
type: Dataset
description: 10-day surf forecast with Strike Scores for Pero Lefts, West Sumba, Indonesia
about: Pero Lefts
  type: TouristAttraction
  geo: GeoCoordinates
    latitude: -9.74
    longitude: 119.15
  description: Pero Lefts is a highly consistent left reef break on West Sumba's south coast that holds as big as it gets. The swell refracts around the headland creating big bowl sections with ample tube time, making this one of Sumba's most rewarding waves for experienced surfers. The wave's consistency means it's rarely flat during the April-October swell season, providing a reliable option when exploring this remote island.
summary:
  best day:
    date: 2026-08-10
    score: 63
    category: Fair
    explanation: Best day in the forecast: 2026-08-10 with a score of 63/100 (Fair)
  firing days count: 0
  overall recommendation: Marginal conditions: Average score 53/100. Surfable but not special. Consider other spots.
forecasts:
  date: 2026-08-05
  day index: 0
  strike score:
    final score: 56
    category: Fair
    category emoji: 😐
    confidence: 1
    confidence explanation: Very high confidence (0-1 day forecast)
    breakdown:
      swell direction:
        score: 21
        out of: 25
        explanation: Good alignment: Swell from 225° is 5° off optimal 220°, still within prime range.
      swell size:
        score: 10
        out of: 25
        explanation: Marginal size: 1.6m is 0.9m from ideal 2.5m.
      swell period:
        score: 14
        out of: 25
        explanation: Moderate period: 14s meets minimum 12s but below ideal 16s. Some groundswell energy present.
      wind:
        score: 11
        out of: 25
        explanation: Onshore/cross-shore: 10 km/h from 125° (SE). Destroying wave quality. Offshore range: 352°-52°.
    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 Pero Lefts. The 1.6m swell from 225° is workable, but conditions aren't ideal. Fine if you're local, but not worth a dedicated trip.
  conditions:
    swell:
      height m: 1.6
      height ft: 5.2
      direction degrees: 225
      direction cardinal: SW
      period s: 14
      explanation: 1.6m (5.2ft) swell from 225° (SW) at 14s period
    wind:
      speed kmh: 10
      speed mph: 6.2
      direction degrees: 125
      direction cardinal: SE
      explanation: 10 km/h (6 mph) from 125° (SE)
    secondary swell:
      height m: 0.6
      direction degrees: 159
      direction cardinal: SSE
      period s: 8
forecasts:
  date: 2026-08-06
  day index: 1
  strike score:
    final score: 54
    category: Fair
    category emoji: 😐
    confidence: 1
    confidence explanation: Very high confidence (0-1 day forecast)
    breakdown:
      swell direction:
        score: 21
        out of: 25
        explanation: Good alignment: Swell from 225° is 5° off optimal 220°, still within prime range.
      swell size:
        score: 12
        out of: 25
        explanation: Marginal size: 1.8m is 0.7m from ideal 2.5m.
      swell period:
        score: 23
        out of: 25
        explanation: Good period: 15s is 94% of ideal 16s. Clean, powerful groundswell.
      wind:
        score: 3
        out of: 25
        explanation: Onshore/cross-shore: 14 km/h from 121° (ESE). Destroying wave quality. Offshore range: 352°-52°.
    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 Pero Lefts. The 1.8m swell from 225° is workable, but conditions aren't ideal. Fine if you're local, but not worth a dedicated trip.
  conditions:
    swell:
      height m: 1.8
      height ft: 5.9
      direction degrees: 225
      direction cardinal: SW
      period s: 15
      explanation: 1.8m (5.9ft) swell from 225° (SW) at 15s period
    wind:
      speed kmh: 14
      speed mph: 8.7
      direction degrees: 121
      direction cardinal: ESE
      explanation: 14 km/h (9 mph) from 121° (ESE)
    secondary swell:
      height m: 0.8
      direction degrees: 140
      direction cardinal: SE
      period s: 4
forecasts:
  date: 2026-08-07
  day index: 2
  strike score:
    final score: 47
    category: Fair
    category emoji: 😐
    confidence: 0.95
    confidence explanation: High confidence (2-3 day forecast)
    breakdown:
      swell direction:
        score: 23
        out of: 25
        explanation: Good alignment: Swell from 223° is 3° off optimal 220°, still within prime range.
      swell size:
        score: 14
        out of: 25
        explanation: Marginal size: 2.1m is 0.4m from ideal 2.5m.
      swell period:
        score: 14
        out of: 25
        explanation: Moderate period: 14s meets minimum 12s but below ideal 16s. Some groundswell energy present.
      wind:
        score: 3
        out of: 25
        explanation: Onshore/cross-shore: 14 km/h from 118° (ESE). Destroying wave quality. Offshore range: 352°-52°.
    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 Pero Lefts. The 2.1m swell from 223° 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: 223
      direction cardinal: SW
      period s: 14
      explanation: 2.1m (6.9ft) swell from 223° (SW) at 14s period
    wind:
      speed kmh: 14
      speed mph: 8.7
      direction degrees: 118
      direction cardinal: ESE
      explanation: 14 km/h (9 mph) from 118° (ESE)
    secondary swell:
      height m: 0.8
      direction degrees: 141
      direction cardinal: SE
      period s: 4
forecasts:
  date: 2026-08-08
  day index: 3
  strike score:
    final score: 50
    category: Fair
    category emoji: 😐
    confidence: 0.92
    confidence explanation: High confidence (2-3 day forecast)
    summary: Surfable but not special at Pero Lefts. The 2.4m swell from 222° is workable, but conditions aren't ideal. Fine if you're local, but not worth a dedicated trip.
provider: Strike Mission
date published: 2026-08-04T23:50:13.109Z
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: 23
  out of: 25
  explanation: Good alignment: Swell from 222° is 2° off optimal 220°, still within prime range.
swell size:
  score: 17
  out of: 25
  explanation: Marginal size: 2.4m is 0.1m from ideal 2.5m.
swell period:
  score: 14
  out of: 25
  explanation: Moderate period: 14s meets minimum 12s but below ideal 16s. Some groundswell energy present.
wind:
  score: 3
  out of: 25
  explanation: Onshore/cross-shore: 14 km/h from 121° (ESE). Destroying wave quality. Offshore range: 352°-52°.

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: 2.4
  height ft: 7.9
  direction degrees: 222
  direction cardinal: SW
  period s: 14
  explanation: 2.4m (7.9ft) swell from 222° (SW) at 14s period
wind:
  speed kmh: 14
  speed mph: 8.7
  direction degrees: 121
  direction cardinal: ESE
  explanation: 14 km/h (9 mph) from 121° (ESE)
secondary swell:
  height m: 0.7
  direction degrees: 141
  direction cardinal: SE
  period s: 4
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: 50
  category: Fair
  category emoji: 😐
  confidence: 0.89
  confidence explanation: Moderate confidence (4-5 day forecast)
  breakdown:
    swell direction:
      score: 24
      out of: 25
      explanation: Perfect alignment: Swell from 221° is within 5° of optimal 220°.
    swell size:
      score: 15
      out of: 25
      explanation: Marginal size: 2.2m is 0.3m from ideal 2.5m.
    swell period:
      score: 8
      out of: 25
      explanation: Moderate period: 13s meets minimum 12s but below ideal 16s. Some groundswell energy present.
    wind:
      score: 7
      out of: 25
      explanation: Onshore/cross-shore: 12 km/h from 124° (SE). Destroying wave quality. Offshore range: 352°-52°.
  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 Pero Lefts. The 2.2m swell from 221° 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: 221
    direction cardinal: SW
    period s: 13
    explanation: 2.2m (7.2ft) swell from 221° (SW) at 13s period
  wind:
    speed kmh: 12
    speed mph: 7.5
    direction degrees: 124
    direction cardinal: SE
    explanation: 12 km/h (7 mph) from 124° (SE)
  secondary swell:
    height m: 0.6
    direction degrees: 209
    direction cardinal: SSW
    period s: 6

date: 2026-08-10
day index: 5
strike score:
  final score: 63
  category: Fair
  category emoji: 😐
  confidence: 0.86
  confidence explanation: Moderate confidence (4-5 day forecast)
  breakdown:
    swell direction:
      score: 23
      out of: 25
      explanation: Good alignment: Swell from 217° is 3° off optimal 220°, still within prime range.
    swell size:
      score: 13
      out of: 25
      explanation: Marginal size: 2.0m is 0.5m from ideal 2.5m.
    swell period:
      score: 25
      out of: 25
      explanation: Perfect period: 16s is at or above ideal 16s. Long-period groundswell with maximum power.
    wind:
      score: 10
      out of: 25
      explanation: Onshore/cross-shore: 10 km/h from 150° (SSE). Destroying wave quality. Offshore range: 352°-52°.
  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 Pero Lefts. The 2.0m swell from 217° is workable, but conditions aren't ideal. Fine if you're local, but not worth a dedicated trip.
conditions:
  swell:
    height m: 2
    height ft: 6.6
    direction degrees: 217
    direction cardinal: SW
    period s: 16
    explanation: 2.0m (6.6ft) swell from 217° (SW) at 16s period
  wind:
    speed kmh: 10
    speed mph: 6.2
    direction degrees: 150
    direction cardinal: SSE
    explanation: 10 km/h (6 mph) from 150° (SSE)
  secondary swell:
    height m: 0.7
    direction degrees: 221
    direction cardinal: SW
    period s: 14

date: 2026-08-11
day index: 6
strike score:
  final score: 50
  category: Fair
  category emoji: 😐
  confidence: 0.83
  confidence explanation: Low confidence (6-7 day forecast)
  breakdown:
    swell direction:
      score: 20
      out of: 25
      explanation: Good alignment: Swell from 213° is 7° off optimal 220°, still within prime range.
    swell size:
      score: 20
      out of: 25
      explanation: Good size: 2.7m is within 15% of ideal 2.5m.
    swell period:
      score: 14
      out of: 25
      explanation: Moderate period: 14s meets minimum 12s but below ideal 16s. Some groundswell energy present.
    wind:
      score: 5
      out of: 25
      explanation: Onshore/cross-shore: 13 km/h from 126° (SE). Destroying wave quality. Offshore range: 352°-52°.
  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 Pero Lefts. The 2.7m swell from 213° 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: 213
    direction cardinal: SSW
    period s: 14
    explanation: 2.7m (8.9ft) swell from 213° (SSW) at 14s period
  wind:
    speed kmh: 13
    speed mph: 8.1
    direction degrees: 126
    direction cardinal: SE
    explanation: 13 km/h (8 mph) from 126° (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: 44
  category: Poor
  category emoji: 💤
  confidence: 0.8
  confidence explanation: Low confidence (6-7 day forecast)
  breakdown:
    swell direction:
      score: 20
      out of: 25
      explanation: Good alignment: Swell from 213° is 7° off optimal 220°, still within prime range.
    swell size:
      score: 13
      out of: 25
      explanation: Marginal size: 2.0m is 0.5m from ideal 2.5m.
    swell period:
      score: 8
      out of: 25
      explanation: Moderate period: 13s meets minimum 12s but below ideal 16s. Some groundswell energy present.
    wind:
      score: 12
      out of: 25
      explanation: Onshore/cross-shore: 9 km/h from 118° (ESE). Destroying wave quality. Offshore range: 352°-52°.
  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 Pero Lefts. Either swell direction (213°), size (2.0m), or wind (9 km/h from 118°) is unfavorable. Consider other spots or wait for better conditions.
conditions:
  swell:
    height m: 2
    height ft: 6.6
    direction degrees: 213
    direction cardinal: SSW
    period s: 13
    explanation: 2.0m (6.6ft) swell from 213° (SSW) at 13s period
  wind:
    speed kmh: 9
    speed mph: 5.6
    direction degrees: 118
    direction cardinal: ESE
    explanation: 9 km/h (6 mph) from 118° (ESE)
  secondary swell:
    height m: 0.4
    direction degrees: 143
    direction cardinal: SE
    period s: 4

date: 2026-08-13
day index: 8
strike score:
  final score: 62
  category: Fair
  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 209° is 11° off optimal 220°, workable but not ideal.
    swell size:
      score: 19
      out of: 25
      explanation: Marginal size: 2.6m is 0.1m from ideal 2.5m.
    swell period:
      score: 14
      out of: 25
      explanation: Moderate period: 14s meets minimum 12s but below ideal 16s. Some groundswell energy present.
    wind:
      score: 16
      out of: 25
      explanation: Onshore/cross-shore: 6 km/h from 225° (SW). Destroying wave quality. Offshore range: 352°-52°.
  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 Pero Lefts. The 2.6m swell from 209° is workable, but conditions aren't ideal. Fine if you're local, but not worth a dedicated trip.
conditions:
  swell:
    height m: 2.6
    height ft: 8.5
    direction degrees: 209
    direction cardinal: SSW
    period s: 14
    explanation: 2.6m (8.5ft) swell from 209° (SSW) at 14s period
  wind:
    speed kmh: 6
    speed mph: 3.7
    direction degrees: 225
    direction cardinal: SW
    explanation: 6 km/h (4 mph) from 225° (SW)
  secondary swell:
    height m: 0.4
    direction degrees: 157
    direction cardinal: SSE
    period s: 5

date: 2026-08-14
day index: 9
strike score:
  final score: 51
  category: Fair
  category emoji: 😐
  confidence: 0.8
  confidence explanation: Very low confidence (8-10 day forecast, conditions may change)
  breakdown:
    swell direction:
      score: 18
      out of: 25
      explanation: Moderate alignment: Swell from 210° is 10° off optimal 220°, workable but not ideal.
    swell size:
      score: 16
      out of: 25
      explanation: Marginal size: 2.3m is 0.2m from ideal 2.5m.
    swell period:
      score: 8
      out of: 25
      explanation: Moderate period: 13s meets minimum 12s but below ideal 16s. Some groundswell energy present.
    wind:
      score: 11
      out of: 25
      explanation: Onshore/cross-shore: 10 km/h from 128° (SE). Destroying wave quality. Offshore range: 352°-52°.
  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 Pero Lefts. The 2.3m swell from 210° is workable, but conditions aren't ideal. Fine if you're local, but not worth a dedicated trip.
conditions:
  swell:
    height m: 2.3
    height ft: 7.5
    direction degrees: 210
    direction cardinal: SSW
    period s: 13
    explanation: 2.3m (7.5ft) swell from 210° (SSW) at 13s period
  wind:
    speed kmh: 10
    speed mph: 6.2
    direction degrees: 128
    direction cardinal: SE
    explanation: 10 km/h (6 mph) from 128° (SE)
  secondary swell:
    height m: 0.7
    direction degrees: 141
    direction cardinal: SE
    period s: 4

Strike Mission
type: Organization