juliensimon/dst-index

Dst Geomagnetic Index (Hourly)

Part of the Space Weather Datasets collection on Hugging Face.

Hourly Disturbance Storm Time (Dst) index from WDC Kyoto, the standard measure of geomagnetic storm intensity. Covers 2000-01-01 to 2026-04-01 with 190,623 hourly readings.

Dataset description

The Dst index measures the strength of the ring current — a toroidal electric current flowing in the magnetosphere. During geomagnetic storms, the ring current intensifies and Dst drops sharply (e.g. -100 to -500 nT for major storms). This index is the primary metric used by satellite operators and power grid managers to assess storm severity.

Dst complements the Kp/Ap indices (available in our space-weather-indices dataset) by providing hourly resolution vs. 3-hourly/daily.

The ring current is a toroidal band of 10-200 keV ions (primarily H+ and O+) trapped in the inner magnetosphere at geocentric distances of 3-8 Earth radii. During quiet times, the ring current produces a modest depression of the surface magnetic field (Dst around -20 to +10 nT). When a CME or high-speed stream arrives with sustained southward interplanetary magnetic field (Bz < 0), enhanced convection electric fields inject fresh particles from the plasma sheet into the ring current, causing Dst to plunge rapidly during the storm main phase. The largest storms in the space age reached Dst below -500 nT (November 2003, March 1989), while the Carrington Event of 1859 is estimated at approximately -850 nT.

Dst is derived from the horizontal field component (H) at four low-latitude magnetometer stations: Hermanus (South Africa), Kakioka (Japan), Honolulu (Hawaii), and San Juan (Puerto Rico). By using near-equatorial stations, the measurement isolates the symmetric ring current signature from the auroral electrojet contributions that dominate at higher latitudes. The hourly cadence resolves the storm main phase (typically 6-12 hours of rapid decrease) and the recovery phase (1-7 days of gradual return to baseline as ring current particles are lost through charge exchange with geocoronal hydrogen and wave-particle scattering into the loss cone).

The Dst index has direct applications in satellite operations: empirical models relate Dst excursions to increased satellite surface charging, single-event upset rates in electronics, and thermospheric density enhancements that accelerate orbital decay. The Burton equation and its variants use solar wind parameters (velocity, density, Bz) to predict Dst in near-real-time, making this dataset valuable for training machine learning models that forecast storm intensity from upstream L1 measurements.

Schema

Column	Type	Description
datetime	datetime	Observation time (UTC, hourly)
dst_nt	int	Dst value in nanotesla (nT). Negative = disturbed.
daily_mean_nt	int	Daily mean Dst (nT)
quality	string	Data quality: "final" (definitive), "provisional", or "realtime"
is_storm	bool	True if Dst <= -50 nT
storm_intensity	string	"quiet" (> -50), "weak" (-50 to -100), "moderate" (-100 to -250), "intense" (-250 to -500), "super" (< -500)

Quick stats

• 190,623 hourly readings (2000-01-01 to 2026-04-01)
• 5,787 storm hours (Dst <= -50 nT)
• Deepest storm: -406.0 nT on 2024-05-11 02:00
• Data quality: 149,040 final, 39,408 provisional, 2,175 realtime

Usage

from datasets import load_dataset

ds = load_dataset("juliensimon/dst-index", split="train")
df = ds.to_pandas()

# Major storms (Dst < -100)
major = df[df["dst_nt"] < -100].sort_values("dst_nt")

# Storm frequency by year
df["year"] = df["datetime"].dt.year
storms_per_year = df[df["is_storm"]].groupby("year").size()

# Dst time series around a specific storm
storm = df[(df["datetime"] >= "2024-05-10") & (df["datetime"] <= "2024-05-15")]

# Compare with Kp index (load space-weather-indices dataset)
# Both datasets can be joined on date for cross-analysis

Data source

WDC for Geomagnetism, Kyoto. Three quality tiers:

• Final (1957-2020): Definitive, quality-checked values
• Provisional (2021-2025): Visually screened but not final
• Real-time (recent): Quicklook values, may be revised

Update schedule

Daily at 13:00 UTC via GitHub Actions.

Related datasets

• space-weather-indices — Daily Kp, Ap, F10.7 indices
• solar-flare-events — Individual flare detections
• space-track-tle-history — Orbital element history (for drag analysis)

Pipeline

Source code: juliensimon/space-datasets

Support

If you find this dataset useful, please give it a ❤️ on the dataset page and share feedback in the Community tab! Also consider giving a ⭐️ to the space-datasets repo.

Citation

If you use this dataset, please cite:

@dataset{dst_index,
  author = {Simon, Julien},
  title = {Dst Geomagnetic Storm Index (Hourly)},
  year = {2026},
  publisher = {Hugging Face},
  url = {https://huggingface.co/datasets/juliensimon/dst-index}
}

Data source

WDC for Geomagnetism, Kyoto

License

MIT (pipeline code). Dst data: free for non-commercial use per WDC Kyoto terms.