Show me the best surf for:
Run python manage.py seed_spots && python manage.py fetch_forecasts.
Wave energy (kJ) measures the power of predicted waves from both size and period.
It's more reliable than height alone — a small long-period wave carries the same energy as a much larger short-period one, and will surf far better.
We sum up to three swell trains (primary + secondary + tertiary), since stacking swells create bigger waves than any one alone.
Wave height is combined significant swell height: √(H₁² + H₂² + H₃²) — organised swell only, no wind chop.
Rough energy ranges:
~100 kJ just about surfable ·
200–1000 kJ increasingly punchy ·
1000–5000+ kJ heavy / dangerous.
Formula: E ≈ 1.96 · Hs² · T² (kJ/m of crest, deep-water seawater).
Surf score (1–10) takes the energy and applies a wind cleanliness factor. Offshore winds leave it untouched. Onshore winds penalise it up to 70%, scaled by strength. The result is mapped to a smooth 1–10 curve for easy day comparison.
Pro tip: note the energy on a small but surfable day at your local — that's your personal baseline for future forecasting.