WSW stands for west-southwest, one of the 16 compass points used in weather reports to describe the direction from which the wind is blowing. A WSW wind originates from a bearing of roughly 247.5 degrees, placing it halfway between west and southwest on the compass rose. This abbreviation shows up in everyday forecasts, marine advisories, aviation weather reports, and wind energy monitoring, and understanding what it actually means can help you make better sense of how weather systems move through your area.
How WSW Fits Into the Compass Rose
Weather services describe wind direction using a system of compass points that divides a full 360-degree circle into segments. The simplest version uses four cardinal directions: north (N), east (E), south (S), and west (W). Adding the midpoints between those gives you eight points, including southwest (SW). Subdivide once more and you get the 16-point compass rose, which is the standard system used in most public weather forecasts. WSW sits between west (270°) and southwest (225°), centered on 247.5°. In practice, a wind labeled WSW could come from anywhere in a range spanning roughly 236° to 259°.
The 16-point system strikes a balance between precision and readability. Meteorologists working with raw data often use exact degree bearings, but those numbers are hard for most people to picture. Saying “winds from 248 degrees” does not help you visualize which direction to face. Saying “WSW winds” immediately tells you the wind is coming from a direction slightly south of due west. Some specialized applications, like ship navigation, use an even finer 32-point compass, but 16 points is the sweet spot for general weather communication.
Wind Direction Means Where It Comes From
One of the most common points of confusion is what “direction” actually refers to when talking about wind. A WSW wind blows from the west-southwest toward the east-northeast. It does not blow toward the west-southwest. This convention is the opposite of how we describe ocean currents, where a “westward current” moves toward the west. Wind direction always indicates the origin, not the destination.
This distinction matters practically. If a forecast says “WSW winds at 15 mph,” and you are standing outside facing into the wind, you would be looking roughly toward the west-southwest. Anything downwind of you, like smoke, pollen, or a storm, would be carried off toward the east-northeast. Sailors and pilots internalize this quickly because their safety depends on it, but for the average person reading a weather app, the from-not-to convention is worth knowing.
How Wind Direction Gets Measured
Traditional weather stations use a wind vane, a device with a flat tail that swings freely on a vertical axis. The tail catches the wind and points the arrow into the direction the wind is coming from. Modern automated stations use electronic sensors that report direction as a degree bearing, which software then converts into compass-point abbreviations like WSW for public-facing forecasts.
Wind rarely blows from a perfectly steady direction. Gusts shift, and local turbulence causes the vane to swing back and forth. Weather reports typically give a time-averaged direction, often over a two-minute or ten-minute window depending on the reporting standard. That averaged value is what gets rounded to the nearest compass point. So a reported WSW wind might have been swinging between 240° and 260° during the averaging period. If you are watching a live weather station readout and notice the direction flickering between WSW and W, that is normal variability, not a malfunction.
What WSW Winds Often Mean for Weather
Wind direction is one of the clues forecasters use to figure out what kind of air mass is heading your way. In the midlatitudes of the Northern Hemisphere, WSW winds often accompany the passage of weather systems. After a cold front sweeps through, winds commonly shift to a westerly or west-southwesterly direction as the system moves east. These post-frontal WSW winds tend to bring drier, more stable air behind the front, though the specifics depend heavily on geography, season, and what air mass is sitting to your west-southwest.
In coastal areas, WSW winds can have very different implications depending on which coast you live on. Along the U.S. East Coast, a WSW wind blows from the interior toward the ocean, which usually means drier conditions and warmer temperatures in summer since the air has been heated over land. Along the U.S. West Coast, a WSW wind comes off the Pacific Ocean, carrying moisture that can produce clouds, fog, or rain when it hits coastal mountains. The same compass abbreviation can mean sunshine in one region and drizzle in another.
WSW Winds and Lake-Effect Snow
One of the most dramatic weather phenomena tied to specific wind directions is lake-effect snow, common in the Great Lakes region of the United States and Canada. These intense, localized snowstorms happen when cold air flows over relatively warm lake water, picking up moisture and dumping it as heavy snow on downwind shores. The wind direction determines which communities get buried.
Research into heavy lake-effect snowstorms around the eastern Great Lakes identified a set of conditions closely linked to these events. Among them, surface wind direction ranging from south-southwest to west-northwest was one of the key factors, along with surface temperatures between about −10°C and 0°C and a large temperature difference between the lake surface and the air above it.
1Academia.edu / International Journal of Climatology. Synoptic climatology of lake-effect snowfall conditions in the eastern Great Lakes region A WSW wind, falling squarely within that directional range, can set up classic lake-effect snow bands. Because lake-effect snow is so directionally dependent, a shift of just a few compass points can mean the difference between three feet of snow and clear skies for towns only a few miles apart.
How Terrain Channels and Redirects Wind
The WSW direction reported at a weather station does not always reflect what the large-scale weather pattern is doing. Terrain has a powerful effect on surface winds, funneling them along valleys, deflecting them around ridges, and accelerating them through gaps. A broad weather system producing westerly winds aloft might show up as WSW or even SSW at a station sitting in a valley that runs north-south.
A long-term study in the Kitakami Basin in Japan examined over 15,000 channeling events across 23 years of data to understand how valleys reshape wind. The researchers found two distinct patterns. In one, called forced channeling, wind gets physically steered to run parallel to the valley axis when the large-scale wind direction already roughly aligns with the valley. In the other, called pressure-driven channeling, the wind blows along the valley even when the large-scale winds are blowing across it, because pressure differences between the two ends of the valley create their own local flow.
2Meteorological Applications. Climatological study of airflow channelling in relation to surface geostrophic windThis is worth keeping in mind if you live in a valley, a mountain pass, or near a coastline with prominent headlands. The wind direction your local station reports may be a channeled version of a different large-scale wind. If your station consistently reads WSW while stations on open ground nearby read W or SW, terrain channeling is the likely explanation.
WSW in Aviation Weather Reports
Pilots encounter wind direction in a slightly different format than the general public. Aviation weather reports, known as METARs, express wind direction in degrees rounded to the nearest 10, using a three-digit notation. A WSW wind at about 250° and 12 knots would appear as “25012KT” in a METAR. The compass-point abbreviation WSW does not actually appear in these coded reports, but pilots mentally translate the degree bearing to a compass direction when planning approaches and departures.
Wind direction matters enormously for airport operations because aircraft take off and land into the wind whenever possible. A WSW wind means the active runway should ideally be oriented so planes approach from the east-northeast and land heading toward the WSW. Airports with runways aligned close to this axis will operate smoothly in WSW wind conditions. Airports without that alignment may face crosswind limitations, requiring pilots to use specific techniques to land safely or, in extreme cases, diverting to another airport. Runway orientation decisions made during airport design take long-term wind direction data into account, and locations where WSW winds dominate will typically have at least one runway favoring that direction.
Wind Direction and Wind Energy
For wind turbines, the direction the wind blows from is not just a weather detail — it directly affects how much electricity gets generated. Modern horizontal-axis wind turbines need to face into the wind to capture energy efficiently. A mechanism called a yaw drive rotates the nacelle, the housing at the top of the tower, so the rotor disc stays perpendicular to the incoming wind. If a WSW wind shifts to W and the turbine does not track that change quickly enough, the misalignment causes aerodynamic losses and puts extra mechanical stress on the structure.
Even moderate misalignment between the rotor and the actual wind direction leads to meaningful drops in power output and increased wear on components.
3Processes. AI-Based Wind Tracking and Yaw Control System for Optimizing Wind Turbine Efficiency Traditional yaw control relies on readings from a wind vane mounted on top of the nacelle, but these sensors respond to wind that has already been disturbed by the spinning blades and the nacelle itself. Newer approaches use predictive algorithms to anticipate directional shifts before they happen, rather than just reacting to historical sensor data.4Energy Conversion and Management. Maximum power extraction for wind turbines through a novel yaw control solution using predicted wind directions For a wind farm in a region where prevailing winds swing between WSW and W throughout the day, even a few degrees of better tracking can add up to a measurable increase in annual energy production.
Reading WSW on a Weather App or Forecast
When you see “WSW 18 mph” on your weather app, here is what you are actually being told. The wind is arriving from the west-southwest at a sustained speed of 18 miles per hour. “Sustained” usually means averaged over a period of about two minutes in U.S. National Weather Service reports. Gusts, which are brief spikes in wind speed, are reported separately when they exceed the sustained speed by a certain margin, and they may come from a slightly different direction than the sustained wind.
Most apps also display wind direction as an arrow or on a small compass graphic. Be careful with these — some apps show an arrow pointing in the direction the wind is going (toward the ENE for a WSW wind), while others show an arrow indicating where the wind comes from. If you are not sure which convention your app uses, check a day when you can feel the wind yourself and compare.
Forecast discussions from the National Weather Service often describe expected wind shifts in compass-point terms: “Winds WSW at 10 to 20 mph, becoming WNW after midnight.” A shift from WSW to WNW suggests a frontal passage or a change in the pressure pattern, rotating the wind clockwise (a “veering” wind in meteorological language). Veering winds in the Northern Hemisphere generally indicate warm air advection or the approach and passage of a weather system. If you see a forecast calling for winds to veer from SSW through WSW to WNW over the course of a day, you can reasonably expect a frontal boundary to move through your area during that period.
Why Compass Points Still Beat Degrees for Most People
There is an ongoing tension in weather communication between precision and usability. Degree bearings are more precise. A forecast could say “winds from 251 degrees” instead of “WSW winds.” But studies in weather communication consistently find that the general public processes compass directions more intuitively than numeric bearings. Most people can immediately picture west-southwest on a mental compass. Almost nobody can picture 251 degrees without converting it to a compass direction first.
The 16-point system does sacrifice some precision. Each compass point covers a 22.5-degree arc, so “WSW” could mean anything from roughly 236° to 259°. For most everyday purposes, that level of resolution is fine. You do not need to know whether the wind is coming from 241° or 254° to decide whether to set up your tent with the door facing away from the wind. For applications where precision matters, like wind energy siting or aviation crosswind calculations, the full degree bearing is used behind the scenes, and the compass abbreviation serves as a convenient label for general communication.
Veering, Backing, and What Shifts From WSW Tell You
Forecasters pay close attention not just to what direction the wind is blowing at a given moment, but to how it changes over time. A clockwise shift, say from SSW to WSW to WNW, is called veering. A counterclockwise shift, from WNW to WSW to SSW, is called backing. In the Northern Hemisphere, veering winds at the surface are generally associated with warm air moving in from the south, while backing winds suggest cold air pushing down from the north.
If you notice winds shifting from SSW to WSW and then to W or WNW over several hours, you are likely watching a cold front pass through. The air behind the front tends to be cooler, drier, and more stable, and skies often clear. If winds back from W to WSW to SW, it can signal an approaching warm front or a deepening low-pressure system, which usually means increasing clouds and a rising chance of precipitation. Paying attention to these directional trends can give you a rough sense of what is coming even before checking the forecast.
Wind shifts are also meaningful at altitude. When wind veers with height (blowing from a more southerly direction near the surface and a more westerly direction aloft), it indicates warm air advection through the lower atmosphere. This setup can destabilize the air column and contribute to thunderstorm development, which is one reason severe weather forecasters track directional wind shear closely. A surface WSW wind combined with a WNW wind at upper levels tells a forecaster something quite different from a surface WSW wind paired with an upper-level wind from the same direction.