Weather data preparation · Windows 64-bit · Version 4.0.0
SWAT-Met Studio 4.0: Automated NASA POWER Weather Data Preparation for QSWAT, ArcSWAT and SWAT+
Download daily meteorological data, generate station grids, integrate DEM elevations, visualize terrain and export SWAT2012-format weather text files—all from one Windows desktop workspace.
Daily meteorological information is essential for modelling rainfall–runoff processes, evapotranspiration, streamflow and watershed water balances with the Soil and Water Assessment Tool (SWAT). Preparing weather datasets for numerous stations and long periods often involves downloading data, identifying missing observations, assigning elevations and creating precise weather input formats.
SWAT-Met Studio 4.0 brings these tasks together in a standalone Windows application. It accesses NASA POWER daily weather data and generates SWAT2012-format weather text files for use with QSWAT and ArcSWAT workflows. For SWAT+ projects, the files can be imported through the SWAT+ Editor SWAT2012 weather-data import workflow.
1. Software at a Glance
| Version | 4.0.0 |
|---|---|
| Platform | 64-bit Windows (standalone MSI installer) |
| Weather source | NASA POWER Daily Point API |
| Daily variables | Precipitation, maximum/minimum temperature, relative humidity, solar radiation, wind speed |
| Elevation options | NASA POWER MERRA-2 metadata or user-supplied DEM |
| Main output | SWAT2012-format station weather text files and matching station indexes |
| Other exports | Processed station CSVs, station table CSV, maps (PNG/TIFF/PDF/SVG), run summary |
| Trial | One completed processing run before activation |
2. What Is New in Version 4?
Integrated weather workspace
Define the region, simulation years, spacing and selected weather variables in one interface, with station tables and processing logs.
DEM-based station elevations
Use NASA elevations or load a DEM, sample the original raster and exclude stations on NoData pixels or outside the DEM footprint.
Terrain map and exports
Review station coverage over an elevation map and export PNG, TIFF, PDF or SVG maps at 72–2400 DPI.
Cleaner results
Receive final SWAT files, processed daily station CSVs and a README summary in numbered export folders.
3. NASA POWER Daily Weather Variables
Download any of the five weather categories individually or process them together. Temperature includes both daily maximum and minimum values.
| Weather category | NASA POWER parameter | Use |
|---|---|---|
| Precipitation | PRECTOTCORR | Daily rainfall inputs |
| Maximum temperature | T2M_MAX | Daily maximum air temperature |
| Minimum temperature | T2M_MIN | Daily minimum air temperature |
| Relative humidity | RH2M | Daily relative humidity |
| Solar radiation | ALLSKY_SFC_SW_DWN | Daily solar input |
| Wind speed | WS10M | Daily wind input |
4. Grid Creation, DEM Integration and Terrain Review
Set southern, northern, western and eastern study-area boundaries; select start/end years and grid spacing in decimal degrees. A station preview allows inspection before downloading. Where needed, the regular grid extends slightly northward or eastward to cover the requested extent.
For elevations, choose NASA POWER MERRA-2 metadata or use an existing DEM. The DEM can establish the geographic study extent; weather stations are retained only on valid raster pixels. The source DEM is not modified. A valid coordinate reference system and elevation units in metres are required.
The built-in terrain preview shows station positions and an elevation legend. Export the map as PNG, TIFF, PDF or SVG, or export the station table to CSV for GIS analysis and documentation.
5. Exact SWAT Weather Text File Formats
Version 4.0 exports SWAT2012-format text files (.txt), with one file per station and an accompanying index for each weather category. These are not advertised as directly generated SWAT+ weather files.
| Weather variable | Station index | Example station files |
|---|---|---|
| Precipitation | pcp.txt | pcp1.txt, pcp2.txt, … |
| Temperature | tmp.txt | tmp1.txt, tmp2.txt, … |
| Relative humidity | rh.txt | rh1.txt, rh2.txt, … |
| Solar radiation | solar.txt | solar1.txt, solar2.txt, … |
| Wind speed | wind.txt | wind1.txt, wind2.txt, … |
Index files include station ID, station name, latitude, longitude and elevation, and each station name corresponds to a weather-file name. Temperature weather files contain daily maximum followed by minimum temperature.
ID,NAME,LAT,LONG,ELEVATIONImporting into modelling workflows
- QSWAT: Use the generated SWAT2012-format text weather data through a supported SWAT2012 import workflow.
- ArcSWAT: Use the prepared station files with the appropriate SWAT2012 weather-data import steps.
- SWAT+: Use the SWAT+ Editor's SWAT2012 weather-data import process; do not assume the files are native SWAT+ output.
6. Missing-Value Handling and Data Quality
The application detects missing weather observations and prepares complete daily time series using documented filling rules. For most variables, missing records are filled with the preceding valid value, while leading gaps use the first valid observation. For missing solar data before 1984, the application uses the average of valid solar observations for the same station and selected period. If a selected variable has no valid data, processing stops.
Automated gap-filling improves continuity but does not guarantee that infilled weather values represent local conditions accurately. Researchers should inspect the processed CSVs and compare NASA POWER data with observed station records when available, particularly in mountainous regions or where long gaps occur.
7. Organized Output Structure
A completed processing run is saved with the selected year range and a numbered suffix so subsequent runs do not overwrite earlier exports.
SWAT_1984_2025_001/
├── SWAT_format/
│ └── SWAT weather files and matching station indexes
├── Stations_data/
│ └── Daily station CSV files (after missing-value filling)
└── README.txtThe README.txt summarizes the region, years, station count, weather variables, elevation source and processing information. Repeating the export for the same period creates an incremented folder such as SWAT_1984_2025_002.
8. How to Use SWAT-Met Studio 4.0
- Define the study area. Enter geographic bounds or select a DEM to use its extent.
- Set the period and spacing. Choose start/end years and the station interval.
- Select the elevation source. Choose NASA POWER elevations or a DEM.
- Inspect stations. Preview the adjusted grid, terrain and station table.
- Choose variables and output folder. Select one or all five weather categories.
- Generate and review outputs. Monitor progress and inspect the SWAT files, processed CSVs and README.
9. Research Applications
SWAT-Met Studio can support watershed rainfall–runoff modelling, water-balance studies, regional and ungauged catchment analysis, climate variability studies and large-basin weather-data preparation. DEM filtering and station maps are especially helpful when planning simulations across complex terrain. The graphical workflow may also help students and researchers who are unfamiliar with R or Python scripting.
As with any gridded or reanalysis-derived weather product, data suitability should be evaluated for each watershed. Station-grid density alone does not establish finer source-data resolution or improve local observation quality.
10. Installation, Free Trial and Activation
Download the SWAT-MetStudio-4.0.0-Setup.msi installer for 64-bit Windows. The application bundles its required dependencies; separate Python or R installations are not needed. Internet connectivity is required to retrieve NASA POWER data.
Free trial: One complete weather-data processing run is available before activation. Further processing runs require software activation. The Version 4.0 release lists a US$10 global activation price; consult the official purchase page for current information. Activation uses a request code associated with the user's computer.
11. Download, Manual and Video Tutorial
Technical questions or issues? Email swatmetstudio@gmail.com or report reproducible problems through the GitHub Issues page.
12. Independent Development and Community Collaboration
SWAT-Met Studio has been independently developed without dedicated external development funding. The project reflects an effort to make daily weather input preparation more accessible, reproducible and efficient for the hydrological modelling community.
Feedback from QSWAT, ArcSWAT and SWAT+ users is welcome. Opportunities to collaborate with the SWAT development community on weather data workflows, GIS integration, software improvements and scientific applications would also be appreciated.
13. Conclusion
SWAT-Met Studio 4.0 combines NASA POWER downloads, station-grid design, optional DEM elevation extraction, terrain review, missing-value handling and SWAT2012 weather text-file generation in a single Windows application. Its purpose is to reduce repetitive data preparation work so researchers can devote more attention to simulation setup, calibration, validation and hydrological interpretation.
