Guide to weather parameters, data, indexes, icons and charts

Guide to weather parameters, data, indexes, icons and charts

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.

 

Photo: herrreiprich / unsplash

Wind

Wind direction

The cardinal direction FROM which the wind is blowing. For example, from the northeast (NE) to the southwest (SW).

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 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

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).

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).

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.

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.

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).

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 what is precipitation in simple words

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.

Read the collection of article about skiing and snowboarding

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.

 

Photo: jeremy-bishop / unsplash

Water 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.

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

 

Photos: 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).

 

Photo: jonatan pie / unsplash

Weather condition icon

The icon 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.

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).

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).

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.

Read mini guide to fishing with Windy.app for iOS

 

Photo: anete lusina / unsplash

Trust Level Index

The wind forecast confidence index: green (10) — trust, the forecast is stable and will not change, yellow (5—6) — trust, but the weather may change, red (1) — unstable forecast, don’t trust it. The index is calculated by Windy.app based on the Standard Deviation of wind forecasts of the ECMWF Ensemble global weather model.

Learn more about Trust Level Index

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.

Learn more about CAPE Index

Kite size

Windy.app recommendation of the kite size depending on weather conditions and your weight entered in the profile.

Read the collection of articles about kitesurfing in 2020-2021

Windsurf sail size

Windy.app recommendation of the wind sail size depending on weather conditions and your weight entered in the profile.

Read mini guide to windsurfing with Windy.app for iOS

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Updated on December 25, 2020. Cover photo: bousbia kadhem / unsplash.

Read full guide to Windy.app for iOS and Android, sports mini guides to kite- and windsurfing, and fishing, as well as guides to Windy.app weather forecast models and weather stations, and customization options. There is also a Windy.app Compass to all 100+ features of the app.

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