Wind Speed Converter

Convert wind speed between different units and see Beaufort, hurricane, and tornado scale classifications

Wind Speed Input

Enter the wind speed value
Select the input unit

Results

Wind Speed Classification
Calm
No wind detected
Miles per hour (mph)
0.00 mph
Kilometers per hour (km/h)
0.00 km/h
Meters per second (m/s)
0.00 m/s
Knots (kt)
0.00 kt
Feet per second (ft/s)
0.00 ft/s
Beaufort Scale
0
Calm - Smoke rises vertically

Understanding Wind Speed Units and Conversion

Wind speed is a fundamental measurement in meteorology, aviation, maritime navigation, and everyday weather forecasting. Different regions and industries use various units to measure wind speed, making wind speed conversion an essential skill for professionals and enthusiasts alike. Our comprehensive wind speed converter helps you instantly convert between all major wind speed units while providing valuable context through internationally recognized wind scales.

Common Wind Speed Units

Wind speed can be measured and expressed in several different units, each with its own applications and regional preferences:

  • Miles per hour (mph): Commonly used in the United States for weather forecasts, road signage, and general meteorology. This is the standard unit most Americans encounter in daily weather reports.
  • Kilometers per hour (km/h): The international standard used in most countries worldwide for weather reporting and general purposes. Part of the metric system and used throughout Europe, Asia, and most of the world.
  • Meters per second (m/s): The scientific standard unit used in meteorological research, physics, and engineering applications. Preferred in technical and scientific contexts due to its direct relationship with SI units.
  • Knots (kt): The aviation and maritime standard, where one knot equals one nautical mile per hour. Essential for pilots, sailors, and marine weather forecasts. Used universally in aviation regardless of country.
  • Feet per second (ft/s): Sometimes used in engineering applications and specialized meteorological studies, particularly in the United States for technical wind engineering calculations.

Wind Speed Conversion Formulas

Understanding the mathematical relationships between different wind speed units helps in manual conversions and comprehending the scales involved. Here are the key conversion factors:

From mph:
• km/h = mph × 1.609344
• m/s = mph × 0.44704
• knots = mph × 0.868976
• ft/s = mph × 1.466667

From m/s:
• km/h = m/s × 3.6
• mph = m/s × 2.23694
• knots = m/s × 1.94384

From knots:
• km/h = knots × 1.852
• mph = knots × 1.15078
• m/s = knots × 0.514444

The Beaufort Wind Scale

The Beaufort scale is an empirical measure for describing wind speed based on observed conditions at sea or on land. Developed in 1805 by Admiral Sir Francis Beaufort of the Royal Navy, it remains widely used today. The scale ranges from 0 (calm) to 12 (hurricane force):

  • Beaufort 0 (Calm): Less than 1 mph - Smoke rises vertically, sea like a mirror
  • Beaufort 1 (Light Air): 1-3 mph - Smoke drift indicates wind direction, sea shows ripples
  • Beaufort 2 (Light Breeze): 4-7 mph - Wind felt on face, leaves rustle, small wavelets
  • Beaufort 3 (Gentle Breeze): 8-12 mph - Leaves and twigs move, light flags extend
  • Beaufort 4 (Moderate Breeze): 13-18 mph - Small branches move, dust and paper raised
  • Beaufort 5 (Fresh Breeze): 19-24 mph - Small trees sway, moderate waves on lakes
  • Beaufort 6 (Strong Breeze): 25-31 mph - Large branches move, whistling in wires, umbrellas difficult to control
  • Beaufort 7 (Near Gale): 32-38 mph - Whole trees move, difficulty walking against wind
  • Beaufort 8 (Gale): 39-46 mph - Twigs break from trees, walking impeded
  • Beaufort 9 (Strong Gale): 47-54 mph - Slight structural damage, chimney pots and slates removed
  • Beaufort 10 (Storm): 55-63 mph - Trees uprooted, considerable structural damage
  • Beaufort 11 (Violent Storm): 64-72 mph - Widespread damage, rarely experienced inland
  • Beaufort 12 (Hurricane Force): 73+ mph - Devastating damage, survival difficult

Saffir-Simpson Hurricane Wind Scale

For tropical cyclones and hurricanes, the Saffir-Simpson scale provides a standardized classification based on sustained wind speeds. This scale helps predict potential property damage and flooding:

  • Tropical Storm: 39-73 mph - Not yet hurricane strength, but dangerous conditions
  • Category 1: 74-95 mph - Very dangerous winds, some damage to buildings, power outages
  • Category 2: 96-110 mph - Extremely dangerous winds, extensive damage, widespread power loss
  • Category 3 (Major): 111-129 mph - Devastating damage, electricity and water unavailable for days
  • Category 4 (Major): 130-156 mph - Catastrophic damage, most of area uninhabitable for weeks
  • Category 5 (Major): 157+ mph - Total destruction of buildings, area uninhabitable for months

Enhanced Fujita (EF) Scale for Tornadoes

The Enhanced Fujita scale rates tornado intensity based on wind speeds and damage caused. While tornado wind speeds are difficult to measure directly, the scale provides estimated wind ranges:

  • EF0: 65-85 mph - Minor damage, peels surface off roofs, breaks tree branches
  • EF1: 86-110 mph - Moderate damage, mobile homes pushed off foundations, cars overturned
  • EF2: 111-135 mph - Considerable damage, roofs torn off houses, large trees uprooted
  • EF3: 136-165 mph - Severe damage, entire stories destroyed, trains overturned
  • EF4: 166-200 mph - Devastating damage, well-built houses leveled, cars thrown
  • EF5: 200+ mph - Total destruction, houses swept away, steel structures damaged

How Wind Speed is Used in Different Industries

Different professions rely on specific wind speed units based on their historical development and practical needs:

  • Aviation: Pilots worldwide use knots for wind speed reporting, as it directly relates to nautical miles used in aviation navigation. Airport weather reports (METARs) always express wind in knots.
  • Maritime: Sailors and marine weather forecasts use knots, maintaining a centuries-old tradition that links speed to nautical miles and the earth's latitude lines.
  • Weather Forecasting: Public forecasts use mph in the US and km/h in most other countries to match the units familiar to local populations.
  • Scientific Research: Meteorologists and researchers prefer m/s for its compatibility with other SI units and ease of mathematical calculations.
  • Wind Energy: Wind turbine specifications typically use m/s, though project planning may convert to local units for public communication.
  • Construction and Engineering: Building codes and wind load calculations may use various units depending on regional standards, with conversions essential for international projects.

Wind Pressure and Force

Wind speed relates directly to wind pressure and force through mathematical relationships. Wind pressure increases with the square of wind speed, meaning doubling the wind speed quadruples the force. This explains why high winds become exponentially more dangerous as speeds increase.

The dynamic wind pressure formula is: Pressure = 0.00256 × V², where V is wind velocity in mph and pressure is in pounds per square foot. This relationship is crucial for structural engineering, explaining why buildings must be designed to withstand increasingly large forces as wind speeds rise.

Measuring Wind Speed

Wind speed is measured using various instruments, with the most common being:

  • Anemometers: Cup anemometers rotate based on wind speed and are standard at weather stations. Digital versions provide instant readouts in multiple units.
  • Weather Vanes: While primarily for direction, modern versions often include anemometer functionality.
  • Wind Socks: Provide visual indication of wind speed and direction, commonly used at airports.
  • Doppler Radar: Measures wind speed remotely at various altitudes, essential for severe weather detection.
  • Ultrasonic Sensors: Modern devices use ultrasonic technology for precise, maintenance-free measurements.

Safety Guidelines by Wind Speed

Understanding wind speed safety thresholds helps you make informed decisions about outdoor activities:

  • 0-10 mph: Safe for all activities, ideal conditions for outdoor recreation
  • 11-25 mph: Generally safe, but may affect lightweight objects and create dust
  • 26-39 mph: Caution advised, secure loose objects, difficult conditions for cycling
  • 40-57 mph: Dangerous for being outdoors, risk of falling branches, stay indoors if possible
  • 58-73 mph: Very dangerous, structural damage likely, seek sturdy shelter immediately
  • 74+ mph: Hurricane force winds, life-threatening conditions, evacuation may be necessary

Example Conversions with Calculations

Let's walk through some practical conversion examples:

Example 1: Converting a typical highway speed limit of 65 mph to other units:

  • 65 mph × 1.609344 = 104.61 km/h
  • 65 mph × 0.44704 = 29.06 m/s
  • 65 mph × 0.868976 = 56.48 knots
  • This represents Beaufort 12 (Hurricane Force) wind conditions - extremely dangerous!

Example 2: Converting an aviation wind report of 20 knots:

  • 20 knots × 1.15078 = 23.02 mph
  • 20 knots × 1.852 = 37.04 km/h
  • 20 knots × 0.514444 = 10.29 m/s
  • This represents Beaufort 5 (Fresh Breeze) - moderate conditions for flying

When to Use the Wind Speed Converter

Our wind speed converter is essential for:

  • Pilots and aviation professionals interpreting weather reports from different countries
  • Sailors and mariners planning routes and understanding maritime forecasts
  • Weather enthusiasts tracking storms and comparing international weather data
  • Students and researchers working with meteorological data in different units
  • Engineers designing structures and evaluating wind load specifications
  • Outdoor recreation planners assessing safe conditions for activities
  • International travelers understanding local weather forecasts
  • Emergency managers evaluating severe weather threats and evacuation decisions

Whether you're tracking a hurricane, planning a sailing trip, studying meteorology, or simply curious about wind conditions, our comprehensive wind speed converter provides instant, accurate conversions along with contextual information from the Beaufort, Saffir-Simpson, and Enhanced Fujita scales to help you understand what those numbers really mean in practical terms.