ERA5 Reanalysis Downloader

Download ERA5 single-level reanalysis data from Microsoft Planetary Computer without an API key, supporting search, download, and spatial subsetting as NetCDF.

Download ERA5 single-level reanalysis data from Microsoft Planetary Computer (no API key required).

Quick Start

bash

# List available variables
python era5-download.py variables

# Search for data
python era5-download.py search --variable temperature_2m --start-date 2024-01 --end-date 2024-06

# Download as NetCDF
python era5-download.py download --variable temperature_2m --start-date 2024-01 --end-date 2024-03

# Download with bounding box subset
python era5-download.py download -v precipitation -s 2024-01 -e 2024-12 --bbox -10 35 5 45 -o europe_rain.nc

Available Variables

Variable	Units	Description
temperature_2m	K	Air temperature at 2m
precipitation	m	Total precipitation
wind_speed_10m	m/s	Wind speed at 10m
wind_u_10m	m/s	U-component of wind at 10m
wind_v_10m	m/s	V-component of wind at 10m
dewpoint_2m	K	Dewpoint temperature at 2m
surface_pressure	Pa	Surface pressure
sea_level_pressure	Pa	Mean sea level pressure
relative_humidity	%	Relative humidity at 2m
soil_temperature	K	Soil temperature (0-7cm)
snow_cover	%	Snow cover
cloud_cover	%	Total cloud cover
evaporation	m	Evaporation
runoff	m	Total runoff
soil_moisture	m3/m3	Soil moisture (0-7cm)

CLI Reference

text

usage: era5-download [-h] [--version] {search,download,variables} ...

ERA5 Reanalysis Downloader - Download from Planetary Computer

positional arguments:
  {search,download,variables}
    search              Search for ERA5 data
    download            Download ERA5 data as NetCDF
    variables           List available ERA5 variables

options:
  -h, --help            show this help message and exit
  --version             show program's version number and exit

search

text

python era5-download.py search -v VARIABLE -s START [-e END] [--limit N] [--json]

download

text

python era5-download.py download -v VARIABLE -s START [-e END] [-o FILE] [--bbox W S E N] [--skip-existing] [--quiet]

Data Source

Uses Microsoft Planetary Computer STAC API:

• Endpoint: https://planetarycomputer.microsoft.com/api/stac/v1
• Collection: era5-pds
• Format: Zarr (cloud-optimized)
• License: Copernicus ERA5 data license (free for research and commercial use)

No authentication or API key is required.

Requirements

• Python 3.8+
• requests
• xarray (optional, for full NetCDF export)
• zarr (optional, for reading cloud-optimized data)

Installation

bash

pip install -r requirements.txt

How It Works

1. Searches Planetary Computer STAC catalog for ERA5 items matching your variable and date range
2. Downloads Zarr-format data chunks
3. Converts and merges into a single NetCDF file
4. Supports spatial subsetting via --bbox
5. Uses .part temp files for safe writes (atomic rename on completion)

Safety

• Safe file writes: downloads to .part temp file, renames on completion
• No API keys or credentials stored or transmitted
• HTTPS-only data source
• Input validation on all parameters