Algorithm design

Instead of hard if/else brackets, the algorithm uses continuous mathematical functions — Gaussian curves, sigmoids, and smooth interpolation — to produce a fine-grained, linear 0–100 % scale. Twelve independent variables are each evaluated as a 0.0–1.0 factor. The factors are split into two groups — safety and fishing — then multiplied within each group and combined:

safetyScore  = round( windF × waveF × lightF × wavePeriodF × 100 )
fishingScore = round( currentF × tideF × moonF × precipF × tempF × speciesDepthF × speciesSeasonF × pressureF × lightFishingF × 100 )
totalScore   = round( safetyScore × fishingScore / 100 )

This multiplicative structure means a single dangerous condition (factor → 0) drives the entire score toward 0 %, while excellent conditions require all factors to be high. The split lets users see whether a low score is due to unsafe weather or poor fishing conditions.

Safety factors

1. Wind Speed & Current Interaction

Wind affects surface drift, which determines whether deep-water gear can maintain bottom contact.

Safety overrides:

• Wind > 15 m/s or gusts > 22 m/s → 0.00 (storm)
• Wind > 12 m/s or gusts > 18 m/s → 0.05–0.25 (strong wind)

Wind–current interaction:

• Wind opposing current (> 120° difference) → positive — slows drift
• Wind aligned with current (< 60°, > 5 m/s) → negative — boat drifts too fast

Below safety threshold, factor decreases smoothly from 1.0 (calm) toward 0.25 (12 m/s). Gusts above 10–12 m/s apply an additional multiplier (0.85–0.92).

2. Wave Height

Affects gear handling efficiency and vessel safety.

3. Light & Time of Day

Deep-water fish feed more aggressively in low light. Factor peaks at dawn and dusk.

4. Wave Period

Short steep waves are dangerous for small boats. Penalty scales with wave height — below 1.0 m wave height, period has no effect.

5. UV & Drift Ice Warnings (Informational)

UV and drift ice are shown as safety warnings in the reason list. They do not directly change Safety score, but they flag important exposure risks for small-boat trips.

• UV ≥ 3: sunscreen reminder
• UV ≥ 6: high UV warning
• UV ≥ 8: very high UV warning
• Sea temperature near/freezing with wind or current drift: drift-ice warning

Fishing factors

5. Ocean Current Speed (Base Score)

The primary fishing driver. A Gaussian curve centred at 0.4 m/s (σ = 0.22).

When no current data is available, a cautious factor of 0.55 is used — unknown current should not inflate the score.

6. Tidal Phase

Tidal phases dictate biological rhythms at depth and nutrient exchange.

When no tide data is available, a neutral 0.75 default is used.

7. Moon Phase

Controls the strength of tidal pull — spring tides reach deeper into the water column.

8. Precipitation

• Dry or light (≤ 0.5 mm/h) → 1.00
• Moderate (0.5–2 mm/h) → 0.93
• Heavy (> 2 mm/h) → 0.85

9. Sea Temperature

• ≥ 3°C → 1.00
• < 3°C → 0.92 (reduced fish activity)

10. Barometric Pressure

11. Species Habitat Depth & Water Column

When a species is selected, NoFish applies a habitat-depth factor based on where that species is typically targeted in the water column (for example upper water, mid-water, or close to bottom over deep ground).

• If local seabed depth is within the species' typical habitat range → no penalty (factor 1.00)
• If depth is outside the range → gradual penalty (down to ~0.65)
• Reason text explains whether depth is optimal, suboptimal, or outside typical habitat

12. Species Seasonality

Species are scored with month-based season windows (prime, shoulder, off-season). This affects the fishing score even when weather is identical.

• Prime season → factor 1.00
• Shoulder season → factor 0.90
• Off-season → factor 0.78

Best fishing windows

The Score page highlights up to 2 non-overlapping windows with the highest average score. The window type depends on your selected fishing method:

• Hours with any danger-level condition are excluded
• The algorithm picks the longest stretch within 5 points of the best average
• If every hour has a danger condition, "No safe fishing periods" is shown
• Windows are shown regardless of how low the total score is — even 5 % is shown if safe

In the hourly table, Total score cells within a best window are highlighted with a blue border.

Net-specific fishing windows (6–8 hour soaks)

When you select "Fishing with net" as your method, the algorithm shifts from 1–3 hour windows to 6–8 hour overnight soak windows. This recognizes that net fishing has fundamentally different safety and logistics constraints than active methods.

A net-specific window requires:

• Set hour: Safety score ≥ 65, no danger conditions, ideally after 21:00
• Pickup hour: Safety score ≥ 65, no danger conditions, ideally before 06:00 local time
• Soak duration: 6, 7, or 8 hours (the algorithm finds all valid soaks)
• Overnight bonus: +10 points to the average score if deployment is after 21:00 AND retrieval is before 06:00

Example: If conditions are calm at 22:00 but will worsen by 04:00 retrieval, the window is flagged as risky and loses the overnight bonus.

Score colour coding