Sustained wind and gusts: why they are not the same field data

When you look at a forecast and see “wind at 20 km/h,” the figure seems fairly straightforward. But there is often another number beside it: gusts of 35, 45, or 50 km/h. They are not two ways of saying the same thing. Sustained wind describes wind speed over a given period. Gusts are brief, more intense increases in speed. For certain types of fieldwork, that difference can matter much more than the average.

What sustained wind is

Sustained wind represents an average speed over a measurement interval. It is useful for understanding the prevailing conditions during a period. If the forecast shows sustained wind of 15 km/h, that does not mean the wind will remain at exactly 15 km/h the entire time. It may decrease. It may increase. And there may be considerably stronger gusts. Looking only at the average can therefore leave out the most intense moments of the event.

What a gust is

A gust is a brief increase in wind speed. You can have relatively moderate sustained wind and, at the same time, significantly stronger gusts. For example:

Sustained wind: 18 km/h

Gusts: 42 km/h

If you looked only at the first figure, you might interpret the situation quite differently from what the gusts indicate. For some decisions, those peaks are precisely what matters.

Why Vienor uses gusts for wind alerts

Vienor evaluates wind alerts using forecast gust speed. The user sets a threshold in km/h for each rule. If a gust at or above that value appears within the configured window, the condition can generate an alert. Sustained wind remains useful information and may appear as context in the notification. But the gust is the main trigger. The goal is to detect when the wind may exceed the level you defined as relevant, even if the overall average is lower.

The same wind does not mean the same thing for every task

There is no single wind speed that automatically turns wind into a problem. It depends on what you are doing. Conditions that may be acceptable for one task may be unsuitable for another. This becomes especially clear when it comes to spraying. It is not enough to know whether “it is windy.” You need to consider how strong the wind is, when it will occur, and which other weather conditions accompany it.

Wind and spraying

Vienor includes a spraying windows feature that analyzes weather conditions hour by hour. Wind is one of the main variables in that evaluation. Other conditions, including humidity and forecast precipitation, are also considered. The result is presented as an indication that helps identify more favorable, marginal, or unfavorable hours for an application. This changes the question. Instead of:

What will the wind be like today?

You can ask something more specific:

During which hours are conditions more suitable for this task?

A daily average can hide important changes

Weather does not happen in 24-hour blocks. A day may begin with light wind, have several hours of strong gusts, and settle again in the afternoon. If you look only at a daily summary, those changes may remain hidden. That is why Vienor uses hourly forecasts for alerts. Conditions are reevaluated every 30 minutes over a horizon of up to three days. This makes it possible to detect when a gust exceeds the configured threshold, even if conditions during the rest of the day are different.

Each field can have its own rule

Alerts are configured for each field. This means you do not necessarily need to apply the same criteria to every location. You can define the gust speed you want to monitor and the time window during which you want to monitor it. Vienor automatically reviews the forecast and compares future values against that rule. When it finds a condition that exceeds the threshold, it can generate a push or email notification.

An alert does not mean the wind will actually reach that speed

This is an important point. Vienor works with weather forecasts. If an alert indicates that gusts above a certain value are expected, it means the weather model is forecasting that condition. It is not a real-time measurement taken by a sensor in the field. Forecasts can change as new data becomes available. That is why Vienor retrieves and evaluates them again periodically. The value lies in automatically detecting when the forecast begins to show a condition that you have defined as relevant.

From data to a condition

A forecast may show sustained wind, gusts, direction, and other variables. But having more numbers does not necessarily make a decision easier. An alert rule helps reduce some of that noise. You define a condition:

Notify me if forecast gusts exceed 40 km/h in this field.

From that point on, Vienor looks for that condition in the forecast. Not because 40 km/h is a universal limit. But because it is the limit you chose to monitor.

Configure your wind alerts in Vienor

In Vienor, you can create wind rules with a specific gust threshold for each field. The system automatically analyzes the hourly forecast every 30 minutes and can detect conditions within a horizon of up to three days. You can also review spraying windows to identify when weather conditions are more favorable for an application.

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