Weather elements and data used in the Windy.app
There are more than 50 different weather parameters, data, indexes, icons and charts you can get in Windy.app for iOS and Android. And we add the new ones all the time.
You can find these parameters and data in several places in the app: in the pre-set weather profiles for 10+ sports and outdoor activities, weather widgets on the Home screen or a spot, in the Weather Archive and on the big Wind and Precipitation map of the world.
To make sure you don't get lost getting a weather forecast, read this detailed and complete guide.
Atmosphere
Wind
Wind direction
The cardinal direction FROM which the wind is blowing. For example, from the northeast (NE) to the southwest (SW).
Learn more about wind direction
Wind direction º
The direction FROM which the wind is blowing (degrees). Clockwise: north — 360 º (0 º), east — 90 º, south — 180 º, west — 270 º.
Wind speed
The measurement of moving air velocity: 3.4—5.5 meters per second, m/s — gentle breeze, 10.8—13.8 m/s — strong breeze, 24.5—28.4 m/s — storm, ≥ 32.7 m/s — hurricane. Other units: miles per hour, mph, kilometers per hour (kph), knots (knt: 0.514 m/s, 1.15078 mph, 1.852 kph, 1 nautical mile per hour), beaufort (Beaufort wind force scale).
Wind rose
The traditional wind rose is a circle with colored bars sticking out its center. It could be 8, 16, or 360 bars in it.
Wind speed compare chart
The comparison of the moving air velocity from different weather models: 3.4—5.5 meters per second, m/s — gentle breeze, 10.8—13.8 m/s — strong breeze, 24.5—28.4 m/s — storm, ≥ 32.7 m/s — hurricane. Other units: miles per hour, mph, kilometers per hour (kph), knots (knt: 0.514 m/s, 1.15078 mph, 1.852 kph, 1 nautical mile per hour), beaufort (Beaufort wind force scale).
Wind gust
A brief increase of the moving air velocity, usually for no more than 20—30 seconds. The higher the speed, the higher the gusts: 3.4—5.5 meters per second, m/s — gentle breeze, 10.8—13.8 m/s — strong breeze, 24.5—28.4 m/s — storm, ≥ 32.7 m/s — hurricane. Other units: miles per hour, mph, kilometers per hour (kph), knots (knt: 0.514 m/s, 1.15078 mph, 1.852 kph, 1 nautical mile per hour), beaufort (Beaufort wind force scale).
Learn where the wind gusts come from
Wind gust compare chart
The comparison of wind gusts (a brief increase of the moving air velocity, usually no more than 20—30 seconds) from the different weather models. The higher the wind speed, the higher the gusts: 3.4—5.5 meters per second, m/s — gentle breeze, 10.8—13.8 m/s — strong breeze, 24.5—28.4 m/s — storm, ≥ 32.7 m/s — hurricane. Other units: miles per hour, mph, kilometers per hour (kph), knots (knt: 0.514 m/s, 1.15078 mph, 1.852 kph, 1 nautical mile per hour), beaufort (Beaufort wind force scale).
Learn more about compating wind gusts
Deviation Index
The wind forecast confidence index representing the spread between the data and the average: 0–2 m/s (0–4.4 mph) — green, 2–4 m/s (4.4–8.9 mph) — amber, >4 m/s (>8.9 mph) — red. If it's small, you may use the forecast as your guidance. If it's big, look at the parameter as a probable error, think about a wind interval and be cautious.
Learn more about Deviation Index
Hurricanes and typhoons
Tropical cyclones (scientific term for typhoons or hurricanes) are "fed" with warm and humid air. They form over the ocean due to hot temperatures and water that evaporates from the surface of the ocean.
Learn more about hurricanes and typhoons
Kite size
Windy.app recommendation of the kite size depending on weather conditions and your weight entered in the profile.
Read how to choose kiteboard kite size and the collection of articles about kitesurfing in 2021
Windsurf sail size
Windy.app recommendation of the wind sail size depending on weather conditions and your weight entered in the profile.
Read how to choose windsurf sail size and mini guide to windsurfing with Windy.app for iOS.
Temperature
Air temperature
The physical quantity expressing how hot or cold the air is. Units: Celsius (ºC), Fahrenheit (ºF) and Kelvin (K).
Learn what is air temperature in a simple explanation
Air temperature compare chart
The comparison of the physical quantity expressing how hot or cold the air is from different weather models. Units: Celsius (ºC), Fahrenheit (ºF) and Kelvin (K).
Air temperature top station
The physical quantity expressing how hot or cold the air is at the ski resort's highest station. Units: Celsius (ºC), Fahrenheit (ºF) or Kelvin (K).
Learn what is snow forecast and how it works
Air temperature bottom station
The physical quantity expressing how hot or cold the air is at the ski resort’s lowest station. Units: Celsius (ºC), Fahrenheit (ºF) or Kelvin (K).
Feels like temperature
The temperature perceived by humans. It depends on wind speed, humidity and other parameters, which can alter our perception. Therefore, it may be lower or higher than the air temperature. Units: Celsius (ºC), Fahrenheit (ºF) and Kelvin (K).
Learn what is feels like temperature and why it is important for sports and outdoors
Bicycle riding temperature
The temperature perceived by humans while riding a bicycle. It depends on wind speed, humidity and other parameters, which can alter our perception. Therefore, it may be lower or higher than the air temperature. Units: Celsius (ºC), Fahrenheit (ºF) and Kelvin (K).
Learn what is bicycle riding temperature
Dew point temperature
The temperature to which the air needs to be cooled so that water condensate is released from it (dew appears). Units: Celsius (ºC), Fahrenheit (ºF) and Kelvin (K).
Learn what is dew point in a simple explanation
Freezing level
The altitude line above which the snow stops melting. It descends in cold and humid areas, and rises in dry and warm areas. Unit: meters (m) or feet (ft) above seal level.
Learn why is there a snow on the top of the mountains
Freezing level chart
The chart showing the altitude line above which the snow stops melting. It descends in cold and humid areas, and rises in dry and warm areas. That is, the farther from the equator, the lower the line. Units: meters (m) or feet (ft) above seal level.
Learn more about freezing level chart
Clouds
Clouds
The percentage (%) of cloud coverage of the sky. For clarity, you see the layers: one — low cloud cover, two — mid, three — high. The more layers, the harder it is for the sun to appear. The thickness of layers is also important.
Learn about differrent types of clouds
Cloud base
The altitude line in the atmosphere where the clouds are located. Units: meters (m) or feet (ft) above sea level.
Clouds and precipitation chart
Clouds — the percentage (%) of the cloud coverage of the sky. One layer — low cloud cover, two — mid, three — high. The thickness of layers is also important. Precipitation — one rain drop or a snowflake — light rain or snowfall, two — heavy, and the like. Units: millimeters (mm), inches (in).
LCL (Lifted Condensation Level)
LCL is Lifted Condensation Level or the height at which the relative humidity of an air parcel (a very small amount of fluid) reach 100% with respect to liquid water when it is cooled by dry lifting. It is a good approximation of the cloud base.
Precipitation
Precipitation
The amount of atmospheric moisture — rain or snow. Heavy rain is 15—50 millimetres, mm (0.5—1.9 inches, in) in 12 hours, heavy snowfall is 7—20 centimetres, cm (2.7—7.4 in) in 12 hours.
Learn the different types of precipitation
Chance of rain (Probability of precipitation, PoP)
Probability of precipitation based on the immediate likelihood of rain forming and The percentage of the area covered by that precipitation from 0% to 100%.
Learn more about how do we measure precipitation
Rain and snow chart
The chart showing the amount of atmospheric moisture. Heavy rain is 15—50 millimetres, mm (0.5—1.9 inches, in) in 12 hours, heavy snowfall is 7—20 centimetres, cm (2.7—7.4 in) in 12 hours.
Precipitation compare chart
The comparison of rain and snow data from different weather models. Heavy rain is 15—50 millimetres, mm (0.5—1.9 inches, in) in 12 hours, heavy snowfall is 7—20 centimetres, cm (2.7—7.4 in) in 12 hours.
Relative humidity
The measurement unit of water vapor in the air. Optimal relative humidity for humans is 40—60 percent (%).
Snow precipitation
The amount of snow falling from the sky. Heavy snowfall is 7—20 centimetres, cm (2.7—7.4 in) in 12 hours.
Learn more about snow precipitation
Snow depth
The amount of snow in the vertical plane. The minimum snow depth for skiing at a ski resort below 2000 meters, m (6561 feet, ft) is 15 centimetres, cm (6 inches, in), above 2000 m: from 50 centimetres, cm to 1 meter, m (20—40 in).
Fresh snow
The date of appearance of fresh snow. Attention: it can make fractures and cliffs unnoticeable.
Last snowfall
The date of the last snowfall. Attention: heavy snowfall followed by slow warming and rain can lead to the creation of dangerous avalanche conditions.
Learn more how to avoid a snowfall when winter hiking the mountains
Pressure
Atmospheric pressure at sea level
The weight of the atmosphere, which can affect a person's well-being and objects on earth. At sea level, the normal pressure is 760 millimeter of mercury, mmHg, (29.92 inch of mercury, inHg, 1013.25 hectopascals, hPa). The pressure is different at different heights, regions and weather conditions.
Learn how atmospheric pressure works
Atmospheric pressure at sea level chart
The chart of the atmosphere weight, which can affect a person's well-being and objects on earth. At sea level, the normal pressure is 760 millimeter of mercury, mmHg, (29.92 inch of mercury, inHg, 1013.25 hectopascals, hPa). The pressure is different at different heights, regions and weather conditions.
Atmospheric pressure at sea level compare chart
The comparison of the atmosphere weight from different weather models. The pressure may affect a person's well-being and objects on earth. At sea level, the normal pressure is 760 millimeter of mercury, mmHg, (29.92 inch of mercury, inHg, 1013.25 hectopascals, hPa). The pressure is different at different heights, regions and weather conditions.
Isobars
The lines that connect the points of the same atmospheric pressure on the weather map. Isobars that are close to one another mean high wind speed.
Weather fronts
Warm weather fronts (red arcs)
The boundary between cold and warm air masses where warm air rises to the surface of cold air. Warm weather front brings rains, sometimes with thunderstorms, the sky is usually completely overcast at a distance of more than 2,400 km. Warm fronts pass in a few days.
Learn more about warm weather fronts
Cold weather fronts (blue arcs)
The boundary between cold and warm air masses where cold air cuts the flow of warm air. Cold weather front brings colder air and good visibility.
Learn more about cold weather fronts
Stationary weather fronts (red and blue arcs)
The mix of warm and cold weather fronts where areas of cold and warm air alternate.
Occluded weather fronts (purple arcs)
Weather fronts that will appear in the nearest future — they will become warm (red) or (blue) weather fronts.
Low-pressure troughs (orange arcs)
The troughs that form when isobars make a sharp bend around the lowest-pressure region.
Weather conditions icon
The icons showing what the weather is like: sun — clear sky during the day, two rain drops — heavy rain, crescent moon without clouds — clear night sky, and so on.
Learn the list of weather symbols and icons used in the Windy.app
CAPE Index
An indicator of atmospheric instability, including cumulus clouds, showers, thunderstorms, and squalls: <0 joules/kilogram (J/kg) — stable (no mentioned phenomena), 0-1000 J/kg — slight instability (light), 1000-2500 J/kg — moderate, 2500-3500 J/kg — high, ≥ 3500 J/kg — very high.
Jeremy Bishop / Unsplash
Temperature
Sea temperature
The physical quantity expressing how hot or cold the sea water is. Staying too long in water below 17—18 degrees Celsius, ºC (62—64 degrees Fahrenheit, ºF, 290—291 Kelvin, K) may lead to muscle cramps and hypothermia.
Solunar
Solunar forecast chart
The chart of how actively fish are going to bite. It depends on the sunrise/-set, moon phase, day of the month, time of the day, tides. More fish in a chart — more bites.
Learn more about solunar theory
Swell (waves)
Swell size
An average height of a 1/3 of the highest waves in the swell (series of waves). For an amateur surfer the good waves size is from 1 meter, m (3.5 feet, ft) to 3 m (10 ft).
Learn how to read surf forecast like a pro
Swell size and direction chart
Swell size is an average height of a 1/3 of the highest waves in the swell (series of waves). For an amateur surfer 1—3 meters, m (3.5—10 feet, ft) is good. Swell direction is the cardinal direction FROM which the swell is coming. For example, from the northeast (NE) to the southwest (NW). The more directed the swell is when hitting the beach, the stronger the waves.
Read the collection of articles about about surfing in 2020-2021
Swell period
The time between successive waves, or swell frequency. The longer the period, the faster and more powerful the waves. 8 seconds (s) — normal surfing, 11 s — good, 14+ s — great (pure ground swell).
Swell energy
The power of waves formed by a combination of their size and period. Bigger waves plus longer periods — more power. 100 kiloJoule (kJ) — surfable waves at many breaks, 200—1000 kJ — punchy waves, 1000—5000+ kJ — heavy and dangerous waves at some breaks.
Currents
Currents speed
The velocity of moving water induced by wind, breaking waves, temperature. Currents in the same direction help the boat/yacht to move faster. For example, the Gulf Stream max speed is 5.6 miles per hour, mph (9 kilometers per hour, kph), average — 4 mph (6.4 kph), min — 1 mph (1.6 kph). Other units: meters per second (m/s).
Learn how ocean currents works
Currents direction
The cardinal direction TO which the water is moving. For example, to the northeast (NE). Currents in the same direction allow the boat/yacht to move faster, side currents carry it to the side, counter currents lead to speed reduction and/or fuel overrun.
Currents direction º
The direction TO which the water is moving (degrees). Clockwise: north — 360º (0º), east — 90º, south — 180º, west — 270º. Currents in the same direction allow the boat/yacht to move faster, side currents carry it to the side, counter currents lead to speed reduction and/or fuel overrun.
Tides
Tidal chart
The chart of sea level rise and fall. At high tide water flows to the coast, at low tide — from the coast. Tides happen in cycles. Unites: meters (m), feet (ft).
Learn what are the two most common tidal datums in the world: LAT and MLLW
Toomas Tartes / Unsplash
Spot location
A point on the Wind and Precipitation Map at which the spot is located.
Spot coordinates º
The point at which the spot is located in a geographic coordinate system (GCS): latitude (lines perpendicular to equator from 0 degrees (º) at it to 90 º north and south at the poles) and longitude (lines parallel to the equator from 0 º at Greenwich to 180 º at the west and east).
Spot altitude
The height above sea level at which the spot is located. Units: meters (m), feet (ft).
Jonatan Pie / Unsplash
Sunrise / sunset
The time when the sun appears on the horizon and disappears below it. It varies depending on the season and place. Units: hours and minutes (h, m).
Moonrise / moonset
The time when the moon appears on the horizon and disappears below it. It varies depending on the season and place. Units: hours and minutes (h, m).
Moon phases
The illumination of the moon by the sun, depending on its position in its orbit. In the northern hemisphere from right to left: New Moon — no moon; Waxing Crescent — 1/3; First Quarter Moon — half; Waxing Gibbous — 2/3; Full Moon — illuminated circle; Waning Gibbous — 2/3; Last Quarter Moon — half; Waning Crescent — 1/3. In the southern hemisphere phases changes from left to right, and on the Equator — from top to bottom.
Ultraviolet Index (UV Index)
The level of solar ultraviolet radiation in the atmosphere: green (0—2) — low, violet (11—12+) — extreme. Use sun protection, if the index is yellow (3) or higher. Index source: World Health Organization (WHO) and World Meteorological Organization (WMO).
Text: Windy.app team
Cover photo: Bousbia Kadhem / Unsplash
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