What Is a Wind Rose and How to Read One

If you have looked at a weather station website, you have probably seen a circular chart with coloured petals radiating from the centre. That is a wind rose, and it is one of the most efficient ways to visualise wind patterns at a glance.

This guide explains what a wind rose is, how to read it, and why it is valuable for any weather station owner.

What a wind rose shows

A wind rose is a diagram that shows the frequency and strength of wind coming from different directions over a period of time. It answers two questions: "where does the wind usually come from?" and "how strong is it when it blows from that direction?"

Each petal or spoke on the chart represents a compass direction: north, north-east, east, and so on. Wind roses can use 8 directions (N, NE, E, SE, S, SW, W, NW) or 16 directions for more granularity.

How to read it

Reading a wind rose is straightforward once you know what to look for:

1. The centre of the circle represents calm conditions (very little or no wind).
2. Each spoke points outward in the direction the wind is coming from. A long spoke pointing north means the wind frequently comes from the north.
3. The length of each spoke shows how often the wind blows from that direction, relative to the other directions.
4. The colour or thickness of each segment within a spoke shows the wind speed range for that direction. In most wind roses, colours progress from light (calm or light breeze) to dark (strong or gale force).

So a wind rose with a long, dark-coloured spoke pointing south-west tells you the wind most often comes from the south-west, and when it does, it tends to be strong.

What the colours mean

Wind roses typically use a colour scale to represent wind speed bands. The exact ranges vary by implementation, but a common scheme is:

• Light green or light blue → Calm to light breeze (0–12 km/h)
• Medium green or teal → Gentle to moderate breeze (12–28 km/h)
• Orange or amber → Fresh to strong breeze (28–49 km/h)
• Red or dark red → Near gale and above (49+ km/h)

This lets you see at a glance not just the prevailing wind direction, but also the typical strength associated with each direction.

Why it matters for weather station owners

A wind rose reveals patterns that raw numbers cannot. After a few months of data, you might discover:

• Your prevailing wind shifts seasonally (north-westerly in winter, south-westerly in summer)
• Your location has a consistent daily sea breeze from a specific direction
• Storm winds always arrive from the same quadrant
• Certain directions are almost always calm, suggesting a local terrain sheltering effect

This information is useful for gardening (knowing which direction frost or drying winds come from), sailing or kite flying (understanding local wind patterns), and simply understanding your local microclimate better.

How Pro Weather builds a wind rose

Pro Weather generates a wind rose from every anemometer tick recorded by your station. The chart updates automatically as new data arrives, so it reflects your actual local conditions rather than regional averages. You can view it as either an 8-point or a 16-point rose, depending on how much detail you want.

Unlike some platforms that approximate wind direction from averages, the Pro Weather wind rose uses the raw per-tick samples. This means it accurately captures brief shifts and gust directions that would be lost in a simple average.

See your own wind rose

If you have a Davis weather station with an anemometer, your wind data is already being collected. A Pro Weather site will display your wind rose automatically, built from your own observations. Start your site and see your local wind patterns take shape in about five minutes.