Historical Archive
Comprehensive geomagnetic activity archive spanning six decades. Explore yearly Kp Index data, interactive timelines, and detailed records of aurora activity across Alaska and the Arctic.
Quick statistics about our comprehensive Kp Index archive spanning six decades of geomagnetic activity data.
Understanding geomagnetic activity is key to predicting Northern Lights visibility. This archive provides comprehensive tools to explore over 60 years of Kp Index data and discover patterns in aurora activity.
The Kp Index is a planetary-scale geomagnetic index that measures global geomagnetic activity on a scale of 0-9. It's calculated from measurements taken at 13 observatories worldwide, providing a standardized way to assess space weather conditions.
For Aurora Viewing: Higher Kp values (typically 5 or above) indicate stronger geomagnetic storms, which increase the likelihood of visible aurora at lower latitudes. In Alaska, Kp values of 3-4 often produce aurora visible in Fairbanks and Anchorage, while values of 5+ can bring aurora to locations as far south as the continental United States.
For Research: Historical Kp data helps researchers understand solar cycle patterns, seasonal variations in geomagnetic activity, and long-term trends in space weather. This archive spans six complete solar cycles, providing valuable insights into geomagnetic behavior.
1. Explore Multi-Year Charts: Start with the interactive chart below to compare Kp Index values across multiple years. Use the filter buttons to focus on specific periods (last 5 years, solar maximum years, high Kp events) or select individual years from the legend.
2. Dive into Yearly Archives: Click on any year card in the "Yearly Archives" section to view detailed daily records, event timelines, and comprehensive statistics for that specific year. Each year page includes interactive charts, data tables, and geomagnetic activity summaries.
3. Analyze Patterns: Use the chart controls to normalize data, toggle seasonal bands, enable zoom, and adjust visualization options. Compare different decades or solar cycles to identify long-term trends and seasonal patterns in geomagnetic activity.
4. Access Raw Data: All data is available in structured JSON format from our GitHub repository. Each year page includes direct links to the source JSON files for programmatic access and research use.
Scroll down to the multi-year comparison chart. By default, the last 5 years are displayed. Use the legend on the right to toggle individual years on or off.
Use the filter buttons above the chart to focus on specific periods: "Last 5 Years", "Last 10 Years", "Solar Maximum", or "High Kp Events" (years with Kp ≥ 7 storms).
Click any year card in the "Yearly Archives" section below to view detailed daily records, event timelines, and comprehensive statistics for that year.
Very low geomagnetic activity. Aurora typically visible only in polar regions (above 65° latitude).
Moderate activity. Aurora often visible in Alaska (Fairbanks, Anchorage) and northern Canada.
Minor to moderate geomagnetic storm. Aurora may be visible in the northern United States and Europe.
Major geomagnetic storm. Aurora may be visible at mid-latitudes, sometimes as far south as 40° latitude.
Note: These are general guidelines. Actual aurora visibility depends on local weather conditions, light pollution, and the specific characteristics of each geomagnetic event. Higher Kp values increase the probability of aurora visibility but don't guarantee it.
Compare Kp Index across multiple years, normalized to day-of-year (Jan 1 - Dec 31). Use filters, legend search, or the year picker to declutter the chart. Hover to spotlight a year, click to lock the highlight.
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Select any year to explore detailed Kp Index records, interactive charts, and geomagnetic activity summaries.
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The Kp Index measures geomagnetic activity on a scale of 0-9. Higher values indicate stronger aurora activity, making it essential for predicting Northern Lights visibility in Alaska.
Our archive contains over 60 years of daily Kp measurements, allowing you to identify seasonal trends, solar cycle variations, and historical aurora activity patterns.
All data is sourced directly from NOAA Space Weather Prediction Center archives, ensuring accuracy and reliability for research, forecasting, and aurora viewing planning.
Powerful tools and visualizations to help you understand geomagnetic activity patterns and aurora forecasting.
Compare Kp Index values across multiple years with interactive charts. Normalize data, filter by decade, and identify patterns across solar cycles.
Dive deep into individual years with detailed daily records, event timelines, and comprehensive geomagnetic activity summaries.
Access structured JSON data from DGD, DSD, RSGA, and other NOAA reports. All data is sourced directly from NOAA Space Weather Prediction Center.
Identify and explore major geomagnetic storms, high Kp events, and exceptional aurora activity periods throughout the archive.
Compare activity across different solar cycles. Filter by solar maximum and minimum periods to understand long-term geomagnetic patterns.
All data is available in structured JSON format for easy integration into research projects, forecasting models, and data analysis workflows.
Our Kp Index archive is sourced from NOAA Space Weather Prediction Center, the authoritative source for geomagnetic activity measurements.
RSGA (Regionally Summarized Geomagnetic Activity): Daily summaries of geomagnetic activity including Kp Index values, A-Index measurements, and regional variations. ✅ Converted to JSON for 1966-2025 (all years).
DGD (Daily Geomagnetic Data): Detailed daily measurements of geomagnetic indices including Planetary A-Index, Mid-Latitude A-Index, and 3-hour Kp values. ✅ Converted to JSON for 1996-2024.
DSD (Daily Solar Data): Daily solar activity measurements and indices. ✅ Converted to JSON for 1996-2024.
Other Data Types: Events, GEOA (Geomagnetic Event Observation Archive), SGAS (Solar Geophysical Activity Summary), and SRS (Solar Region Summary) are converted for 1996-2024. DPD (Daily Proton Data) is available for 1996-2020.
All converted data is hosted on our GitHub repository in structured JSON format for easy access and visualization.
Original Data Source: All historical geomagnetic data displayed on this page
was originally obtained from the
NOAA Space Weather Prediction Center FTP Space Warehouse
(ftp.swpc.noaa.gov/pub/warehouse).
Data Conversion: We have extracted, processed, and converted the original NOAA data files into structured JSON format. RSGA (Kp Index) is fully converted for 1966-2025. DGD and DSD are converted for 1996-2024. Other types (Events, GEOA, SGAS, SRS) are converted for 1996-2024. DPD is available for 1996-2020.
GitHub Repository: All converted JSON datasets are hosted on our GitHub repository, providing easy access to processed historical geomagnetic data for researchers and developers.
Note: You can access the original raw data files directly from the NOAA FTP Space Warehouse using any FTP client. However, our JSON format provides a more convenient structure for web-based applications and data visualization.