Forecast error,
at every lead time.
Every NWS revision captured at issuance — analyze forecast variance at 6, 12, and 24 hours across 20 stations.
Which stations run hot vs cold vs the forecast?
What you get
Four data products via REST API. Each endpoint returns JSON with station, lead time, and time window parameters.
Lead-time variance curves
MAE and bias at 6, 12, 24, 48, and 72 hours before observation. See exactly when the forecast becomes actionable.
Revision tracking
Every NWS forecast revision captured at issuance with issuance-to-issuance diffs. Know when forecasts shift and by how much.
Verified observations
Forecasts paired with ASOS/AWOS temperature observations. Every data point tagged as verified or preliminary.
API access
REST API with API key auth. Free tier: 5 stations, 100 calls/day. Pro: all 20 stations, 10k calls/day.
How it works
Capture revisions at issuance
We ingest every NWS forecast update for 20 Kalshi market stations, every 5 minutes. Every revision tracked with issuance timestamp.
Compare to verified observations
Each forecast is paired with the actual ASOS/AWOS temperature observation. Verification pairs computed hourly against ground truth.
Serve metrics by station, lead time, and bucket
Bias, MAE, std dev, and correction factors delivered via REST API. Filter by station, lead time window, or temperature bucket.
Coverage and methodology
Transparent data pipeline. No black boxes, no proprietary models. Raw NWS forecasts vs. raw observations.
curl -s "https://api.deltadaemon.com/api/v1/accuracy/by-station/KBOS?days=90" | jq .data{"city_name": "Boston","sample_size": 47,"station_id": "KBOS","stats": {"verification_pairs": 47,"unique_days": 4,"mean_error": 1.19,"std_dev": 3.11,"mae": 2.52,"rmse": 3.3,"abs_error_p50": 2,"abs_error_p90": 5.8,"abs_error_p95": 6.5}}
Start with the data.
Free tier: 5 stations, 100 calls/day. No credit card required. Read the docs first.