Stormchaser Kite

Data Source: ERA5 Reanalysis

ERA5 is the European Centre for Medium-Range Weather Forecasts (ECMWF) global atmospheric reanalysis dataset, accessed via the Open-Meteo API. It provides hourly data at approximately 30 km grid resolution globally.

This database uses 5 years of data (2021–2025) to compute all metrics.

Parameters used:

• Wind speed (10m)
• Wind gusts
• Wind direction
• Air temperature
• Water temperature (sea surface)
• Wave height
• Wave period
• Precipitation
• Cloud cover
• Humidity

What is a "Kiteable Day"

A day counts as kiteable when wind speed reaches ≥16 knots for at least 3 consecutive hours during daytime (sunrise to sunset).

16 knots is the minimum for comfortable kiting on modern equipment with average-sized kites. Only daytime hours are considered — sunrise and sunset times are computed per spot location and per week.

Additional thresholds:

• Strong wind day: a kiteable day (3+ hrs ≥16 kt) where at least 2 hours reach ≥25 knots — small-kite sessions for experienced riders
• Foilable day: ≥10 knots for ≥3 daytime hours — kite foiling requires less wind

Wind Pattern Types

Five categories that help kiters plan sessions:

ERA5 Calibration

ERA5 systematically underestimates wind at many coastal kite spots. The causes include thermal effects (sea breeze), terrain channeling (straits, valleys, bays), and island acceleration — all of which happen below ERA5's 30 km grid resolution.

To compensate, per-spot correction factors (ranging from 1.0 to 1.80) are applied. The correction multiplies all ERA5 wind speed values by the factor before any analysis: corrected_speed = ERA5_speed × factor. For example, a spot with factor 1.5 means ERA5 reports winds approximately 33% lower than reality at that location, so all wind speeds are scaled up by 1.5×.

This correction is applied consistently across all metrics and charts: kite day counts, wind speed distributions, wind rose directions, and the hourly wind heatmap. The wind speeds shown on spot detail pages reflect the corrected (real-world estimated) values, not raw ERA5 output.

Calibration sources:

• Windfinder station data
• Kite travel industry reports (IKO, kite camps)
• Thermal signature analysis (day/night wind ratio from ERA5)

Factor categories:

Ranking & Heatmap

Spots are ranked by annual average kiteable days per week. A higher number means more reliable wind year-round.

The ranking page displays a weekly heatmap — 61 spots × 52 weeks, color-coded by average kite days per week. The color scale runs from grey (0 days) through green and yellow to red (7 days). This lets you visually compare seasonal wind patterns across all spots at a glance.

Click any week column to re-sort all spots by that week’s performance (best on top). This is useful for finding the best destination for a specific travel window. Click “Spot” to reset to the annual ranking.

Spot detail charts:

• Wind Speed Distribution — daily peak wind speeds binned by strength, per month (ERA5-corrected)
• Wind Rose — wind direction × speed from daytime hours across all years
• Hourly Wind Heatmap — average wind speed per hour × month (daytime only, ERA5-corrected), showing when wind peaks during the day
• Wind Quality — gust ratio (gustiness) and percentage of wind from the favourable direction sector
• Year-to-Year Reliability — individual year lines vs. 5-year average to show inter-annual variance