windspeedMonitor

Set up a monitored location

The first visit opens Map. Once sites are saved, the app opens Monitor on return. Sites remain saved in this browser; unsaved Map edits do not alter the monitored forecast or manual conversion.

1. Open the Map tab, choose a location on the map, search for a town, or enter coordinates, and give the site a recognisable name.
2. Enter the reference height from 1 to 200 m above local ground, select the terrain for the height conversion, and check the editable air density.
3. Choose Save & load forecast. The app saves the site and opens the Monitor tab.
4. The Monitoring list shows every saved site with its reference height, current modelled gust and pressure equivalent. Select a site to review its source time, current conditions and seven-day forecast.
5. Use Edit beside a monitored site, or Edit site above its forecast, to return to its settings on Map. Add site starts a new location.
6. Compare model wind speeds, forecast gusts and the displayed equivalent velocity pressure. The manual 10 m converter uses the selected site's saved height, terrain and density.
7. Review the conversion method and weather source before comparing a forecast pressure with a project design pressure.

Read the forecast

Current conditions and forecasts are numerical weather model outputs. They are not measurements from an on-site anemometer. The forecast may change as weather models update, and local exposure can differ from the model grid.

In the hourly forecast, Open-Meteo's wind speed is an instantaneous model value at the timestamp; its gust is the maximum over the preceding hour. Current conditions use the provider's current interval. These values do not establish a measured 10-minute mean wind speed. Source: https://open-meteo.com/en/docs.

Each location has its own height and terrain settings. Forecast wind speeds are supplied at 10 m above ground; the app estimates values at the entered reference height using its stated height profile.

Wind speeds can be displayed or entered in mph, m/s or kph. The manual converter also accepts a separately identified mean wind reading; its velocity pressure does not establish peak qₚ.

Height conversion

The supported reference height z is 1–200 m above local ground. Without a verified WindCalc assessment, v(z) = v(10) × ln(max(z, zmin) / z₀) / ln(10 / z₀), using the selected terrain at both heights. Below zmin the profile is held at zmin.

On Map, open the WindCalc assessment, check Country/Town exposure and the project inputs, calculate its twelve terrain sectors, then choose Use assessment. The snapshot is bound to the site's coordinates, height, terrain and density.

Verified gust sectors use gust(z) = gust(10) × √(E(z)/E(10)), where E is WindCalc's peak-exposure factor including town and applicable orography corrections. WindCalc reanalyses the terrain profile at each height. The model wind line retains the logarithmic profile.

Relative exposure is a screening height transfer, assuming the 10 m gust represents local exposure. It cannot recover absolute hill speed-up unresolved by the weather model grid. Missing terrain, unsupported detailed orography or a manual hill factor without its matching 10 m transfer leaves the comparison unavailable.

Understand the pressure equivalent

The displayed pressure is q = ½ρv² / 1000, with v in m/s and pressure in kN/m². Air density is editable from 0.5 to 2 kg/m³; default 1.226 kg/m³ matches WindCalc.

A forecast gust pressure is not automatically Eurocode design qₚ. Design return-period, seasonal, directional and altitude factors are not reapplied to a forecast gust; no further turbulence multiplier is added.

The comparison matches each hour to the nearest 30° wind-from sector, showing directional design qₚ and forecast/design percentage. Gusts are preceding-hour maxima but direction is instantaneous, so this sector match is approximate. Completed hourly gust intervals are excluded from upcoming forecast peaks.

Seven-day peak percentage can occur in a different hour from peak pressure. A percentage of design pressure is not a structural utilisation or a safe working limit. Changes to the saved site require a matching assessment. Sources: https://eurocodes.jrc.ec.europa.eu/sites/default/files/2021-12/handbook3.pdf and https://open-meteo.com/en/docs.

Weather service configuration

The free Open-Meteo service is available for non-commercial evaluation. Production use on this subscription-based website requires a customer API key under Open-Meteo's terms: https://open-meteo.com/en/terms.

The site operator should set WINDSPEED_OPEN_METEO_API_KEY (or OPEN_METEO_API_KEY) in the server environment. The server then uses Open-Meteo's customer endpoint and keeps the key out of the browser. The data source notice identifies whether a customer key is configured.

Explanations in the app

Click the map or drag the blue pin to set the position.

WindCalc checks shore, town and orography in 12 directions. Review its full inputs before using the assessment.

Used only when no WindCalc assessment is saved. A stale or unavailable directional assessment blocks comparison.

Design qₚ and relative exposure from the actual WindCalc engine

Choose the site and reference height, then calculate and review its WindCalc assessment.

The review uses WindCalc's density of 1.226 kg/m³; using an assessment applies that density to this site. Unchecked terrain and sectors requiring a detailed calculation have no design comparison. A fresh calculation resets individual direction overrides; review and re-enter them in WindCalc if required.

Saved on this browser. Select a site to view its outlook.

Uses the selected site's saved reference height, terrain and density.

Select a point on the map, enter the assessment height and save the site.

The current forecast and seven-day outlook will appear here.

Set a reference height and terrain to see the conversion factor.

Model wind uses v(z) = v(10) × ln(max(z, zmin) / z₀) / ln(10 / z₀), a neutral logarithmic profile. With a checked WindCalc sector, the gust uses √(exposure(z) / exposure(10)); pressure uses that exposure ratio. This assumes the supplied 10 m gust is local to the site: it transfers height and does not recover unresolved hill speed-up in the weather grid. At 10 m the ratio is 1. Unavailable sectors use the logarithmic profile and have no design comparison.

Wind FROM selects the nearest of WindCalc's 12 sectors (±15°). Hourly gusts are preceding-hour maxima paired with an instantaneous direction, so gust-sector matching is approximate. This is a screening comparison, not a structural approval or a working limit.

qₚ equivalent = ½ρ × gust(z)² / 1000, in kN/m². It is a forecast gust pressure for comparison; it is not a Eurocode design qₚ or a net load on a structure. Mean wind gives mean velocity pressure only. No extra turbulence factor is applied to a forecast gust.

“Current” means the provider's modelled current conditions, rather than an on-site instrument. The model wind speed is instantaneous; hourly gusts are maxima over the preceding hour, and current gusts over the preceding 15-minute interval. Updates run every 15 minutes while this page is open. Seven days means today and the next six local calendar days; only hourly intervals ending now or later enter the outlook, with current conditions shown separately. Missing values are shown as unavailable.

Weather data: Open-Meteo · CC BY 4.0. The free service is for non-commercial evaluation. This subscription-based website requires a customer API key before production use.

Method references: JRC wind actions handbook · Forecast API documentation.

Areas in the app

Use these sections to locate the inputs, checks and results shown in the app:

• Choose a site
• New location
• WindCalc · 12 directions
• Monitoring
• Seven-day outlook
• Hourly forecast

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