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ArcWeather Radar provides high-performance, near real-time weather radar coverage across the continental United States (CONUS). Built for speed, efficiency, and scalability, the radar system is designed to deliver consistent updates with minimal latency. Radar data is updated and published approximately every 2 minutes, ensuring you always have access to the most recent view of precipitation and storm activity.

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How It Works

The ArcWeather Radar API follows a simple two-step flow:
  1. Check availability
    Request the status endpoint to determine the latest available radar timestamp.
  2. Request the data
    Use that timestamp to fetch the corresponding radar dataset.
This approach ensures you are always working with a valid, published radar frame.

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Data Format: PMTiles

ArcWeather Radar is delivered using PMTiles, a modern format for storing and serving tiled geospatial data in a single file. Instead of requesting thousands of individual map tiles, PMTiles allows you to:
  • Load radar data from a single file per timestamp
  • Reduce network overhead and request volume
  • Improve performance and caching efficiency
  • Seamlessly integrate with modern map libraries
Each radar frame is distributed as a .pmtiles archive containing all zoom levels.

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Learn More About PMTiles

To understand how PMTiles works and how to integrate it into your application, refer to the official documentation:

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Example Flow

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Step 1 — Get Latest Radar Timestamp

GET https://conus.prod.radar.arcweather.cloud/status.json
Response: 
{
  "healthy": true,
  "latest": "202604022225",
  "timestamps": ["202604022225"]
}

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Step 2 — Request Radar Data

GET https://conus.prod.radar.arcweather.cloud/tiles/202604022225.pmtiles
This returns a PMTiles archive containing the full CONUS radar dataset for that timestamp.

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What Our Radar Looks Like

Radar Tile Example

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Why PMTiles?

ArcWeather uses PMTiles as the primary delivery format because it enables:
  • Faster load times for large geographic areas like CONUS
  • Lower infrastructure and bandwidth overhead
  • Better performance at scale
  • Simplified client-side rendering
This is especially important for applications that require frequent updates and large-area coverage.

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Legacy Tile Support

ArcWeather also offers a traditional XYZ tile-based radar format for compatibility with older systems. However:
  • This format is considered legacy
  • It is less efficient and requires significantly more requests
  • It is not recommended for new implementations
For the best performance and scalability, PMTiles is the preferred and recommended format. To learn more about our tile services, click here.

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Summary

  • Radar updates every ~2 minutes
  • Use /status.json to discover available timestamps
  • Fetch radar data via .pmtiles archives
  • PMTiles provides better performance and efficiency than traditional tiles
  • Legacy tile support exists but is not recommended
Last modified on April 4, 2026