Zak Wind + Waves Forecast

⭐ My Perfect Day

Define your ideal conditions. Days and spots that match will be highlighted with ⭐ in the forecast.

💨 Wind speed

and knots

💨 Gust

and knots

🌊 Wave height

and m

🌊 Wave period

and s

🌧️ Rain

No rain — must be dry Excludes hours with precipitation > 0.1 mm

⏱ Good if rules hold for at least

hours (9am–6pm) Leave empty = all hours must match

How it works: Set rules for any conditions you care about. Leave a rule on "any" to ignore it. Days where the forecast matches your rules get a ⭐ on the day header. Spots with a matching good day get ⭐ on their button.

🌊 Zak Wind & Wave Forecast

A personal wind forecasting tool built for kiters, windsurfers, and anyone who lives by the wind.

📍 Add any spot in the world — any beach, lake, or bay, with its own forecast, wave data, webcam and station link.

📁 Organize into folders — group by region, season, or trip. Switch between your local break and a travel destination in one tap.

⭐ My Perfect Day — set your ideal wind and wave conditions, and the app highlights the best upcoming sessions across all your spots at a glance.

🌍 Best Spots worldwide — explore 150+ top kite and windsurf destinations with best-month info and direct forecast links.

🎯 Calibrate individual spots — compensate for station blockage with direction-specific wind rules, conditioned on speed, gusts, or waves.

📂 Calibrate by folder — apply wave height corrections to an entire region at once.

💾 Export your spots — back up or share your full setup as a text file.

📱 Works on any device — runs in your browser, no login needed. Your data stays on your device.

Colors & Meanings

Wind strength colors (gust-based)

< 15 k

15–20 k

20–25 k

25–30 k

30+ k

Wind = solid • Gusts = dashed • Green line = measured wind

Waves

Bar height uses the same scale as wind (knots on left). 1 meter = 10 knots on chart. Bar color = wave period (s).

3–5 s = Chop

5–7 s = Short

7–9 s = Medium

9–12 s = Long

12+ s = Very long

Example: 1.5m wave appears at "15" on chart. Tooltip shows actual meters.

Sea Quality Scores (1-10)

Two different scores based on activity type:

Wave Riding Score

For surfing, wing foiling. Formula: (Height × Period) / 2.5

High waves + long period = excellent. Short period = choppy.

Flat Water Score

For SUP, kayaking, swimming. Formula: 10 / (1 + (Height/0.3)^1.8) × Period modifier

Small waves + long period = smooth. Chop = bad.

9-10 = Epic

7-9 = Excellent

5-7 = Good

3-5 = Fair

1-3 = Poor

Quick Reference Examples:

Conditions	Wave Score	Flat Score
3m @ 15s	10.0	1.4
2m @ 12s	9.6	3.3
1m @ 8s	3.2	5.3
0.5m @ 10s	2.0	8.6
0.3m @ 12s	1.4	10.0

Spot Indicators

⭐ Star = Wind calibration active

🌊⚙️ Badge = Folder wave calibration active

See Calibration section below for details on all calibration types.

Air Quality Index (AQI)

Based on European Air Quality Index (EAQI). Shows PM2.5, PM10, NO₂, O₃, and SO₂ levels.

Good (0-20)

Fair (21-40)

Moderate (41-60)

Poor (61-80)

Very Poor (81-100)

Extremely Poor (100+)

🎯 Calibration Guide

The app has three independent calibration systems. They work together in a priority chain — spot-level always wins over folder-level.

💨 Spot Wind Calibration

Fine-tune the wind forecast for a specific spot based on its real-world behaviour. Opened with the 🎯 Calibrate button on any selected spot.

How to add a wind rule:

Click sectors on the compass (e.g. N, NE, E)
Choose + Add or − Subtract
Choose Knots or Percent %
Pick a value from the dropdown
Optionally add a wave condition (see below)
Click ➕ Add Rule

Wave condition on wind rules:

Each wind rule can be made conditional on wave height. Check "Only when waves are", choose less/greater than, and set a threshold in meters. The rule will only apply when waves meet that condition.

Example: "Add 10 kts to East wind only when waves < 1.5m" — useful for spots sheltered from swell but exposed to thermal wind.

Indicator: ⭐ star appears on the spot button when it has wind rules. Rules are shown in the list below the compass and highlight on the compass when you hover them.

🌊 Spot Wave Calibration

Adjust the model's wave heights for a specific spot. Found at the bottom of the 🎯 Calibrate modal under "🌊 Wave Height Calibration".

Two independent rules:

Small Waves — waves up to the threshold
Set threshold (e.g. 1m), choose % or cm, set the adjustment value.
Example: Up to 1m → −50% (0.8m becomes 0.4m)

Large Waves — waves over the threshold
Same structure, applied when waves exceed threshold.
Example: Over 1m → −50cm (2m becomes 1.5m)

Priority:

Spot wave calibration overrides folder wave calibration for that spot. If a spot has its own wave rules, folder rules are ignored for it.

Tip: Click 💾 Save Wave Calibration — a green confirmation appears. The Clear button removes it. Changes apply on the next data refresh.

📁 Folder Wave Calibration

Apply a wave height adjustment to all spots in a folder at once. Useful when an entire region has systematically over- or under-estimated waves. Found in Settings → 🌊 Wave Calibration.

How to set it:

Open Settings → 🌊 Wave Calibration
Find your folder's wave calibration card
Set the Small Waves threshold and adjustment
Set the Large Waves threshold and adjustment
Click Save Calibration

Shortcut:

Click the 🌊⚙️ button on any folder header to jump directly to that folder's wave calibration card in settings.

Indicator: When a folder has active wave calibration, a teal 🌊⚙️ badge appears in the folder header next to the spot count. The calibration card in settings also shows a green border and a summary badge, e.g. ≤1m: −50% / >1m: −0.5m.

⚡ Calibration Priority Chain

When multiple calibrations could apply, the app uses this priority order:

1️⃣

Spot Wind Rules

Applied to wind speed per compass direction. Optional wave condition filter.

2️⃣

Spot Wave Rules

Adjusts wave height for this spot. Blocks folder wave rules if present.

3️⃣

Folder Wave Rules

Applies to all spots in the folder that have no spot-level wave rules.

4️⃣

Raw Model Data

No adjustments — forecast shown exactly as received from Open-Meteo.

🌍 Best Wind & Kite Spots in the World

Check spots then press Add:

🌊 Wave Calibration by Folder

Apply wave height adjustments to all spots in a folder. Spots with individual calibration rules will use their own rules instead.

🗂️ Folder History

Folders you've removed are saved here. Restore an entire folder or pick individual spots to bring back.

💾 Export / Import Data

📤 Export

Download all your spots and calibration settings as a JSON file. Use this as a backup or to share your setup.

📥 Import

Load spots from a JSON file. Choose how to handle existing spots:

Merge (add new, keep existing) Replace (overwrite everything)

📂 Choose File

📄 About & Disclaimer

⚠️ Important Disclaimer

This application provides weather forecast data for informational purposes only. We are not responsible for the accuracy, completeness, or reliability of the data presented. Weather conditions can change rapidly and forecasts may be incorrect. Always check multiple sources and use your own judgment before making decisions based on this data. Do not rely solely on this information for activities where safety is a concern.

⚠️ Model Data Only: All wind, gust and wave values are numerical weather model outputs — not real measurements. There are no physical sensors or stations at your spots. The model computes values from atmospheric equations on a grid, typically 1–11 km resolution. Actual conditions at your exact location may differ significantly, especially near coastlines, hills, or sheltered bays. Calibration rules can help tune the model to your local experience.

ℹ️ Data Sources

Wind and weather data provided by Open-Meteo.com — model: ICON Global
Wave data provided by Open-Meteo Marine API
Maps provided by Esri & OpenStreetMap

This application, including its source code, design, user interface, calibration system, scoring algorithms, visual layout, and all related concepts, are the exclusive intellectual property of Yuval Zak and are protected under applicable copyright law.

You may not: copy, reproduce, distribute, modify, reverse-engineer, create derivative works from, sell, or otherwise exploit any part of this application — including its code, design patterns, UX concepts, calibration logic, or scoring systems — without explicit written permission from Yuval Zak.

Wind + Waves Forecast

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