Since 2010 · Powering 2M+ tool runs every month
Since 2010
Add to Chrome

My Toolbox

Automatic Mode

No saved tools yet.

Go Premium
Related tools
🌡️ Heat Index Calculator🌬️ Wind Chill CalculatorSleeping Bag Temperature Rating Guide
Home Page > Miscellaneous > General Tools

💧 Dew Point Calculator

Calculate the dew point temperature from air temperature and relative humidity using the Magnus formula. Includes comfort assessment, frost point, wet-bulb estimate, step-by-step calculation, and interactive dew point chart.

Free to useNo sign-up requiredInstant Results
💧 Dew Point CalculatorTry it now — free ▼

⚡ Quick Examples:

☀️ Hot Humid (30°C, 70%) 🌦️ Mild Day (25°C, 50%) 🌞 Summer Heat (85°F, 80%) ❄️ Cold Morning (5°C, 90%) 🔥 Tropical (35°C, 85%)
💡 Tip: The dew point is a better indicator of comfort than relative humidity. A dew point above 18°C (65°F) feels oppressively humid, regardless of the actual temperature.

Embed 💧 Dew Point Calculator Widget

About 💧 Dew Point Calculator

Welcome to the Dew Point Calculator, a free online tool that calculates the dew point temperature from air temperature and relative humidity. The dew point is a critical weather metric that tells you the exact temperature at which moisture in the air will begin to condense. Whether you are a weather enthusiast, HVAC professional, pilot, farmer, or simply want to understand outdoor comfort, this calculator gives you precise results with step-by-step explanations.

What is the Dew Point?

The dew point (also called the dew point temperature) is the temperature to which air must be cooled, at constant pressure and water vapor content, for saturation to occur. When the air temperature drops to the dew point, water vapor condenses into liquid water, forming dew, fog, or clouds.

Dew Point vs. Relative Humidity

While both measure moisture, they work differently:

For example, 50% humidity at 35°C feels much more oppressive than 50% humidity at 10°C. The dew point captures this difference: the first scenario has a dew point of ~23°C (oppressive), while the second has a dew point of ~0°C (dry).

The Magnus Formula

This calculator uses the Magnus-Tetens approximation, widely used in meteorology and recommended by the World Meteorological Organization:

  1. Calculate the intermediate parameter: α = (a × T) / (b + T) + ln(RH / 100)
  2. Calculate the dew point: Td = (b × α) / (a - α)

Where a = 17.27, b = 237.7°C, T is air temperature in Celsius, and RH is relative humidity in percent. This formula is accurate to within ±0.4°C for temperatures between -45°C and 60°C.

Dew Point Comfort Levels

Meteorologists and weather services use dew point ranges to describe how comfortable the air feels:

Frost Point

When the dew point falls below 0°C (32°F), moisture deposits as frost (ice crystals) rather than liquid dew. The temperature at which this occurs is called the frost point. This calculator automatically detects sub-zero dew points and computes the frost point using modified Magnus constants for ice saturation.

Additional Metrics

Wet-Bulb Temperature

The wet-bulb temperature is the lowest temperature achievable by evaporative cooling alone. It is critical for assessing heat stress (a wet-bulb temperature above 35°C is considered the limit of human survivability). This calculator estimates wet-bulb temperature using the Stull (2011) formula.

Dew Point Depression (Spread)

The dew point depression is the difference between air temperature and dew point. A smaller spread means the air is closer to saturation. Pilots use this to estimate cloud base height: cloud base (in feet) ≈ spread (°C) × 125.

Absolute Humidity

While relative humidity and dew point describe moisture in relative or temperature-based terms, absolute humidity measures the actual mass of water vapor per unit volume of air (grams per cubic meter).

How to Use This Calculator

  1. Enter the air temperature: Type the current ambient temperature. Use a thermometer, weather app, or weather station reading.
  2. Enter the relative humidity: Input the humidity as a percentage (0-100%). Hygrometers, weather stations, and weather apps provide this value.
  3. Select your unit: Choose Celsius or Fahrenheit from the dropdown.
  4. Try quick examples: Use the preset buttons to test common scenarios like summer heat, winter cold, or tropical conditions.
  5. Click Calculate: Press "Calculate Dew Point" to see the dew point, comfort assessment, and all related metrics.
  6. Review results: Explore the dew point value, comfort gauge, condensation animation, step-by-step formula breakdown, and reference chart.

Practical Applications

Weather Forecasting

Meteorologists use the dew point to predict fog, dew, frost, and precipitation. When the temperature approaches the dew point, fog or low clouds are likely to form.

HVAC and Building Science

HVAC engineers monitor dew points to prevent condensation on cold surfaces (windows, pipes, walls). If indoor air reaches the dew point on a cold surface, moisture forms, which can lead to mold growth, corrosion, and structural damage.

Aviation

Pilots use dew point depression to estimate cloud base height and assess fog risk. A small temperature-dew point spread at an airport signals potential fog formation.

Agriculture

Farmers monitor dew points to predict frost risk, plan irrigation, and assess crop disease risk (many fungal diseases thrive in high-humidity conditions near the dew point).

Health and Sports

High dew points impair the body's ability to cool through sweating. Athletes and outdoor workers use dew point readings to assess heat stress risk and adjust activity levels accordingly.

Frequently Asked Questions

What is the dew point?

The dew point is the temperature at which air becomes saturated with moisture and water vapor begins to condense into liquid water (dew). It is a measure of atmospheric moisture. A higher dew point means more moisture in the air. Unlike relative humidity, the dew point provides an absolute measure of how much water vapor is present.

How is dew point calculated?

Dew point is calculated using the Magnus-Tetens formula. First, compute α = (a × T) / (b + T) + ln(RH/100), where a = 17.27, b = 237.7°C, T is air temperature in Celsius, and RH is relative humidity in percent. Then, dew point Td = (b × α) / (a - α). This formula is accurate to within 0.4°C for typical atmospheric conditions.

What does the dew point tell you about comfort?

Dew point is a better indicator of comfort than relative humidity. Below 10°C (50°F) feels dry and comfortable. Between 10-16°C (50-60°F) is pleasant. Between 16-18°C (60-65°F) feels humid. Above 21°C (70°F) is oppressive and potentially dangerous.

What is the difference between dew point and frost point?

When the dew point is above 0°C (32°F), moisture condenses as liquid dew. When it is below freezing, moisture deposits as ice crystals (frost), and the temperature is called the frost point. The frost point uses modified constants for ice saturation and is slightly different from the standard dew point at sub-zero temperatures.

Why is dew point better than relative humidity for measuring comfort?

Relative humidity depends on temperature and can be misleading. Air at 30°C with 50% humidity feels much more humid than air at 10°C with 50% humidity. The dew point provides an absolute measure of moisture content, making it a more reliable indicator of how muggy or comfortable the air actually feels.

Can the dew point be higher than the air temperature?

No, the dew point can never exceed the air temperature. When they are equal, the relative humidity is 100% and the air is fully saturated. In practice, the dew point is always at or below the current temperature.

What is a dangerous dew point?

Dew points above 21°C (70°F) are considered oppressive and can be dangerous during physical activity. Dew points above 24°C (75°F) are extremely dangerous and rare, typically occurring only in tropical coastal areas or during monsoons. At these levels, the human body cannot effectively cool itself through sweating.

Additional Resources

Reference this content, page, or tool as:

"💧 Dew Point Calculator" at https://MiniWebtool.com/dew-point-calculator/ from MiniWebtool, https://MiniWebtool.com/

by miniwebtool team. Updated: Mar 24, 2026

Developer API available: Run this tool from your app, automation, or agent with one JSON HTTP request. View API docs

General Tools:

Top & Updated:

Instagram User ID LookupRandom PickerRandom Name Picker WheelImage ResizerFacebook User ID LookupLine CounterSort NumbersRSD Calculator - Relative Standard DeviationFPS ConverterRandom Quote GeneratorRemove SpacesJob Finder🖱️ Click CounterMAC Address LookupWord to Phone Number Converter📷 OCR / Image to TextSun, Moon & Rising Sign Calculator 🌞🌙✨⬛ Aspect Ratio CalculatorStandard Error CalculatorMAC Address GeneratorRandom Credit Card GeneratorERA CalculatorMerge VideosSum CalculatorPercent Off CalculatorRoman Numerals ConverterLog Base 10 CalculatorSHA256 Hash GeneratorJulian Date ConverterCm to Feet and Inches ConverterMP3 LooperSlope and Grade CalculatorWeight Loss CalculatorBatting Average CalculatorAdd Text to ImageName RandomizerSquare Root (√) CalculatorNumber of Digits CalculatorOctal CalculatorBitwise CalculatorIP Subnet CalculatorRandom Superpower GeneratorPhone Number ExtractorImage SplitterRandom IMEI GeneratorFeet and Inches to Cm ConverterRandom Writing Prompt GeneratorRandom Activity GeneratorAudio SplitterVertical Jump CalculatorRandom Fake Address GeneratorInvisible Text GeneratorText FormatterQuotient and Remainder CalculatorVideo CompressorSalary Conversion CalculatorBCD ConverterRandom Truth or Dare GeneratorOutlier CalculatorHalfway Date CalculatorNumber to Word ConverterEquation of a Line CalculatorFirst n Digits of PiCaffeine Overdose CalculatorBinary to Gray Code ConverterFraction CalculatorYouTube Channel StatisticsRandom Poker Hand GeneratorRandom Movie PickerCompound Growth CalculatorLunar Calendar ConverterSun Position CalculatorEstimation CalculatorFile Size ConverterLeap Years ListLong Division CalculatorMultiplication CalculatorBolt Torque CalculatorSHA512 Hash GeneratorMaster Number CalculatorRandom Birthday GeneratorBingo Card GeneratorName Number Calculator🔍 Plagiarism Checker📅 Date CalculatorLimit CalculatorMD5 Hash GeneratorVideo to Image ExtractorEmail ExtractorInequality SolverMagic 8-BallAI Language DetectorModulo CalculatorCompare Two StringsHebrew Calendar ConverterStair CalculatorImage CompressorURL Extractor🔊 Tone Generator🎰 Gacha Pity CalculatorLong Multiplication CalculatorMultiple Fraction CalculatorOPS CalculatorRandom Video Thumbnail GeneratorCone Flat Pattern (Template) GeneratorArc Length CalculatorPercent Growth Rate CalculatorNumber ExtractorRandom Loadout GeneratorWord Ladder GeneratorFlip VideoRandom Meal GeneratorRandom Emoji GeneratorDomain and Range CalculatorBcrypt Hash Generator / CheckerRemove Lines Containing...Remove Empty LinesRandom User-Agent GeneratorAPI TesterBreak Line by CharactersBroken Link CheckereBay Fee CalculatorLove Compatibility CalculatorRandom Number PickerRandom Object GeneratorAlgebraic Expression SimplifierList of Prime NumbersRadical SimplifierSlugging Percentage CalculatorPercent to PPM ConverterSocial Media Username CheckerRandom Group GeneratorAstrological Element Balance Calculator📊 Bar Graph MakerImage EnhancerAverage Deviation CalculatorScientific Notation CalculatorScientific Notation to Decimal ConverterWhat is my Zodiac Sign?Trigonometric Equation SolverDay of Year CalendarOrder of Operations Calculator (PEMDAS)AI Text HumanizerSigma Notation Calculator (Summation)Chinese Gender PredictorRandom Tournament Bracket GeneratorWAR CalculatorWord Scramble GeneratorRandom Math Problem GeneratorDice RollerAdd Prefix and Suffix to TextHEX CalculatorRandom Line PickerSmall Text Generator ⁽ᶜᵒᵖʸ ⁿ ᵖᵃˢᵗᵉ⁾On Base Percentage CalculatorSocial Media Post Time OptimizerHeight Percentile CalculatorDay of the Year Calculator - What Day of the Year Is It Today?Paycheck Calculator (Take-Home Pay)Proportion CalculatorIP Address to Hex ConverterAI Punctuation AdderAdjust Video SpeedImage CropperAudio ExtractorVideo SplitterWHIP CalculatorList RandomizerSquare Numbers ListField Goal Percentage CalculatorIP Address to Binary ConverterRemove Leading Trailing SpacesSaturn Return CalculatorDMS to Decimal Degrees ConverterSum of Positive Integers CalculatorRandomize NumbersColor InverterFirst Day of AutumnRandom PIN GeneratorJulia Set GeneratorDecibel (dB) CalculatorRatio to Percentage CalculatorSlope Intercept Form CalculatorConnect the Dots GeneratorYouTube Tag ExtractorRandom Chord GeneratorArithmetic Sequence CalculatorRemove Line BreaksVocabulary Quiz GeneratorHelium Balloon Lift CalculatorLottery Number GeneratorReverse VideoWater Usage CalculatorTime Duration CalculatorNumber Pattern FinderRatio CalculatorRemove AccentBackronym GeneratorConvert Video for Twitter (X)Gamertag GeneratorTeam Name GeneratorNickname GeneratorRap Name GeneratorBand Name GeneratorFantasy Name GeneratorFortune Cookie GeneratorDrawing Idea GeneratorJournal Prompt GeneratorDaily Affirmation GeneratorCompliment GeneratorPickup Line GeneratorDad Joke GeneratorRandom Joke GeneratorRandom Fact GeneratorTrivia Question GeneratorHangman Word GeneratorPictionary Word GeneratorCharades GeneratorIcebreaker Question GeneratorNever Have I Ever GeneratorWould You Rather GeneratorRandom Question GeneratorAI Dream InterpreterAI Thank-You Note GeneratorAI Wedding Speech GeneratorAI Press Release GeneratorAI Product Description GeneratorAI Video Script GeneratorAI YouTube Title & Description GeneratorAI Instagram Caption GeneratorAI LinkedIn Headline & Bio GeneratorAI Resume Bullet GeneratorAI Cover Letter GeneratorAI Rap Lyrics GeneratorPDF Flatten ToolUnlock PDF (Owner-Password Removal)PDF to Text ExtractorPDF Page ExtractorPDF Word CounterProtect PDFAdd Page Numbers to PDFReorder PDF PagesDelete PDF PagesRotate PDFJPG to PDFPDF to JPGCompress PDFSplit PDFMerge PDFPT to PX ConverterPX to REM ConverterTola to Gram ConverterIndian Land Unit ConverterMcg to Mg ConverterAI Song Lyrics GeneratorAI Poem GeneratorAI Story GeneratorAI TranslatorAI Text SummarizerMg to Ml ConverterMPH to KMH / KMH to MPHKnots to MPH ConverterCubic Meters to Cubic FeetCubic Feet to Cubic Yards ConverterSquare Feet to Square Meters ConverterSquare Meters to Square Feet ConverterOz to ML ConverterML to Oz ConverterGallons to Liters ConverterLiters to Gallons ConverterKg to Stone ConverterStone to Kg ConverterInches to MM ConverterMM to Inches ConverterMiles to Km ConverterKm to Miles ConverterFahrenheit to Celsius ConverterCelsius to Fahrenheit ConverterBackpack Size CalculatorSurfboard Volume CalculatorTennis Grip Size CalculatorHelmet Size CalculatorGlove Size CalculatorHat Size ConverterSnowboard Size CalculatorSki Size CalculatorBike Size CalculatorSpeedrun Split TimerStableford CalculatorDart Checkout CalculatorBowling Economy CalculatorBatting Strike Rate CalculatorNet Run Rate CalculatorK/D Ratio CalculatorElo Rating CalculatorHeart Rate Recovery CalculatorHiking Time CalculatorRowing Pace CalculatorRunning Age-Grading CalculatorFTP & Power Zones CalculatorBeep Test CalculatorACFT Score CalculatorWilks & DOTS CalculatorWheel Offset CalculatorTire Load Index & Speed Rating LookupCost Per Mile CalculatorLease Buyout CalculatorOctane Mix Calculator2-Stroke Oil Mix CalculatorEngine Displacement CalculatorCouch Fit CalculatorFirewood Cord CalculatorAir Purifier CADR CalculatorDehumidifier Size CalculatorCeiling Fan Size CalculatorCurtain Size CalculatorRug Size CalculatorPicture Hanging Height CalculatorTV Mounting Height CalculatorTV Size CalculatorPond Volume & Liner CalculatorPool Salt CalculatorPool Volume CalculatorWater Heater Size CalculatorEpoxy Resin CalculatorBaluster Spacing CalculatorBaseboard & Trim CalculatorSiding CalculatorDeck Stain CalculatorGrass Seed CalculatorSod CalculatorAsphalt CalculatorCubic Yard CalculatorAntenna Length CalculatorConduit Fill CalculatorSeries/Parallel Capacitor CalculatorInductive Reactance CalculatorRoom Lighting CalculatorLux to Lumens CalculatorLumens to Watts ConverterGenerator Size CalculatormAh to Wh Converter3-Phase Power CalculatorkVA CalculatorAmps to Watts CalculatorWatts to Amps CalculatorResistors in Series CalculatorFriction CalculatorInclined Plane CalculatorMechanical Advantage CalculatorSpeed of Sound CalculatorWave Speed CalculatorBuoyancy CalculatorTerminal Velocity Calculatorde Broglie Wavelength CalculatorPhoton Energy CalculatorE=mc² CalculatorTime Dilation CalculatorKepler's Third Law CalculatorEscape Velocity CalculatorGravitational Force CalculatorBeer-Lambert Law CalculatorNernst Equation CalculatorOsmotic Pressure CalculatorBoiling Point Elevation CalculatorFreezing Point Depression CalculatorPercent Composition CalculatorNormality CalculatorMolality CalculatorpKa to Ka ConverterHenderson-Hasselbalch CalculatorTheoretical Yield CalculatorLimiting Reactant CalculatorElectron Configuration CalculatorInteractive Periodic TableAI Lesson Plan GeneratorAI Quiz GeneratorCitation Generator (APA/MLA/Chicago)Attendance Percentage CalculatorAP Score CalculatorACT Score CalculatorSAT Score CalculatorYouTube Earnings EstimatorRandom RPG Character Generator
Home Page > Miscellaneous > General Tools > 💧 Dew Point Calculator