Uploading Custom Weather Records (CSV / Excel)

First published: October 2026
Last updated: October 23, 2026

[!TIP] If your project uses an on-site weather station, a private mine site rain gauge, or data from local water districts, you can upload your own custom spreadsheet in seconds.

The Climate Simulator accepts standard CSV (Comma-Separated Values) and Excel (.xlsx) files containing daily historical weather records.

File Format Requirements

To ensure smooth processing, organize your spreadsheet with one row per calendar day and clear column headers.

Required & Supported Columns

Your file should include at least three columns: 1. Date: Daily timestamp (supported formats include YYYY-MM-DD, MM/DD/YYYY, or DD/MM/YYYY). 2. Precipitation: Daily rainfall or snow-water equivalent (depth per day). 3. Daily Maximum Temperature ($T_{\max}$): Highest temperature recorded during that calendar day. 4. Daily Minimum Temperature ($T_{\min}$): Lowest temperature recorded during that calendar day.

(Optional) You may also include: - Average Temperature ($T_{\text{avg}}$): If $T_{\max}$ and $T_{\min}$ are missing, the engine can estimate daily ranges based on seasonal averages, though providing both daily maximum and minimum yields the most accurate CLIGEN calibration. - Solar Radiation or Wind: For future evaporation calculations.

Example Spreadsheet Layout

(If using US Customary units, precipitation should be in inches and temperatures in °F).

How to Upload Your File

1. In the Data Source card, click on the Custom Upload tab.
2. Drag and drop your file into the upload dropzone, or click Browse Files to select your file from your computer.
3. The Column Mapping Dialog will automatically appear:
4. Match your spreadsheet's date column to Date Column.
5. Match your precipitation column to Precipitation Column.
6. Match your temperature columns to Tmax and Tmin.
7. Select your file's native units (Metric: mm / °C or Imperial: in / °F).
8. Click Import & Process.

Handling Missing Values & Gauge Outages

In real-world field gauges, occasional power failures or clogged rain buckets create missing entries. The Climate Simulator handles these gracefully:

• Blank cells or NaN: Treated as missing observations.
• Flagged codes (e.g., -999 or M): The importer automatically detects standard missing data flags and converts them to nulls.
• Leap Years: The system natively supports February 29th and accounts for leap year frequencies in all monthly parameter calculations.

[!WARNING] If your custom record contains long stretches of missing data (e.g. 6 consecutive months missing), it is best to filter out those incomplete years using the Date Range Filter so that monthly statistics are not skewed by incomplete records.