21,017 Quality-Controlled Global Stations Active
Weather Vault™
Instant, certified meteorological datasets formatted for EnergyPlus, PVsyst, Carrier HAP, Trane TRACE, HelioScope, and NREL SAM.
Chicago OHare Intl AP, IL, USA
Mean Annual Temp
10.4 °C
50.7 °F
Max Summer Peak
35.8 °C
96.4 °F
Min Winter Low
-24.5 °C
-12.1 °F
Annual Solar GHI
1,420 kWh/m²
Peak Gust Speed
24.1 m/s
54 mph
Choose Weather Data Format
Select your engineering domain below to reveal target simulation formats. All 10 formats are certified and ready for instant in-browser download.
Building Energy & HVAC Simulation
4 FORMATS
EnergyPlus, OpenStudio, Carrier HAP, Trane TRACE, IES-VE, ESP-r
EnergyPlus Weather Format
.epw
FREE
Standard 8-header hourly meteorological dataset (35 variables) for EnergyPlus, OpenStudio, IES-VE.
Primary Software: EnergyPlus, OpenStudio, IES-VE, DesignBuilder, Ladybug Tools.
Content: 35 hourly weather parameters including solar irradiance, dry-bulb, dew-point, humidity, wind, and sky cover.
Content: 35 hourly weather parameters including solar irradiance, dry-bulb, dew-point, humidity, wind, and sky cover.
Peak Heating & Cooling Design Conditions
.ddy
FREE
Statistical 99.6% heating & 0.4% cooling extreme conditions for HVAC equipment sizing.
Primary Software: EnergyPlus, Carrier HAP, Trane TRACE (3D Plus), OpenStudio.
Content: Plaintext EnergyPlus SizingPeriod:DesignDay objects with optical depth clear sky coefficients (taub, taud).
Content: Plaintext EnergyPlus SizingPeriod:DesignDay objects with optical depth clear sky coefficients (taub, taud).
ESP-r ASCII Climate File
.clm
FREE
Standard 6-column thermal simulation climate dataset for European & academic building modeling.
Primary Software: ESP-r, EnergyPlus, Academic Research.
Content: Diffuse solar, dry-bulb (tenths °C), direct normal solar, wind speed, wind direction, and relative humidity.
Content: Diffuse solar, dry-bulb (tenths °C), direct normal solar, wind speed, wind direction, and relative humidity.
Legacy TMY2 ASCII File
.tm2
FREE
Fixed-width 120-byte ASCII format for legacy Carrier HAP (v5), DOE-2.1E, eQUEST, and TRNSYS.
Primary Software: Carrier HAP (v5), eQUEST, DOE-2.1E, TRNSYS, F-Chart.
Content: Fixed character position ASCII records formatted exactly to 1995 NREL specification.
Content: Fixed character position ASCII records formatted exactly to 1995 NREL specification.
Solar PV & Daylighting Modeling
4 FORMATS
NREL SAM, PVsyst, HelioScope, Daysim, Radiance, Ladybug Tools
NREL System Advisor Model Solar CSV
.csv
FREE
Streamlined 15-variable format tailored for solar PV, battery storage, and CSP simulation.
Primary Software: NREL System Advisor Model (SAM), PySAM, PVsyst.
Content: Solar irradiance (GHI, DNI, DHI), ambient temperature, wind, and albedo without building simulation bloat.
Content: Solar irradiance (GHI, DNI, DHI), ambient temperature, wind, and albedo without building simulation bloat.
Daysim / Radiance Daylighting Format
.wea
FREE
Dynamic daylight autonomy & annual illuminance simulation dataset for Daysim and Ladybug Tools.
Primary Software: Daysim, Radiance, Ladybug Tools, Honeybee.
Content: Hourly direct normal and diffuse horizontal solar irradiance for ray-tracing illuminance simulations.
Content: Hourly direct normal and diffuse horizontal solar irradiance for ray-tracing illuminance simulations.
TMY3 / TMYx Comma-Separated Values
.csv
FREE
NREL standard 68-column dataset with paired data source & uncertainty flags.
Primary Software: PVsyst, HelioScope, NREL SAM, Excel Analysis.
Content: Full 68-field NREL layout with barometric pressure in mbar and paired uncertainty quality flags.
Content: Full 68-field NREL layout with barometric pressure in mbar and paired uncertainty quality flags.
PVsyst Meteorological Format
.pvsyst
FREE
Direct import format for PVsyst solar photovoltaic system performance calculations.
Primary Software: PVsyst (v6, v7, v8).
Content: Clean hourly solar irradiance, ambient temperature, wind velocity, and PV array degradation factors.
Content: Clean hourly solar irradiance, ambient temperature, wind velocity, and PV array degradation factors.
Meteorological & Climate Diagnostics
2 FORMATS
EnergyPlus Statistics, Heating/Cooling Degree Days, Rainfall Depth
Weather Statistics & Degree Days
.stat
FREE
Annual & monthly climate summaries, HDD/CDD base temperatures, and solar radiation distributions.
Primary Software: EnergyPlus, Climate Consultant, Excel.
Content: Monthly mean temperatures, diurnal cycles, heating/cooling degree days (base 10°C/18.3°C), and ASHRAE design conditions.
Content: Monthly mean temperatures, diurnal cycles, heating/cooling degree days (base 10°C/18.3°C), and ASHRAE design conditions.
Hourly Liquid Precipitation Depth
.rain
FREE
Hourly rainfall precipitation data (m/hr) for moisture modeling, green roof sizing, and stormwater design.
Primary Software: EnergyPlus, DOE-2, WUFI Moisture Analysis.
Content: 8,760 hourly liquid precipitation depths formatted in exponential scientific notation (m/hr).
Content: 8,760 hourly liquid precipitation depths formatted in exponential scientific notation (m/hr).
Bin Weather Data • MyBinMaker™
PREMIUM
Generate 1°F, 2°F, 5°F, and 1°C temperature bin distribution tables, coincident wet-bulb psychrometrics (Stull formula), 7-day × 24-hr operating schedule masking, and formatted Excel workbooks for this station.
Certified Meteorological Provenance & Data Quality Assurance
All datasets adhere to World Meteorological Organization (WMO No. 100) standards, NOAA/NCEI Integrated Surface Database ground observations, and ECMWF ERA5 solar irradiance reanalysis. Full scientific specifications, conversion physics, and agency citations are published in our technical reference guide.