SWFT monitors five independent Kp index sources in a prioritized fallback chain. If the primary source becomes unavailable, the system automatically switches to the next available source to maintain continuous coverage.
Local time — non-linear scale: Kp 0–4 (60%), 4–7 (30%), 7–9 (10%)
Primary source. Local K-index measured at the Boulder, Colorado magnetometer station. A single-station index rather than the planetary average, so values may differ slightly. Promoted to primary due to superior reliability — the NOAA planetary feed occasionally reports anomalous 0.0 values during active conditions.
Local time — non-linear scale: Kp 0–4 (60%), 4–7 (30%), 7–9 (10%)
First fallback. Planetary Kp derived from a network of ground-based magnetometers worldwide. Published as 1-minute estimates and downsampled to 15-minute averages. This is the same feed used by NOAA's official space weather dashboards. Demoted from primary due to recurring data anomalies where the feed reports 0.0 during active geomagnetic conditions.
No data points
Second fallback. The NOAA Kp forecast feed includes "estimated" entries for the current 3-hour window alongside future predictions. Lower temporal resolution (3-hour blocks) but available even when real-time feeds are down.
Local time — non-linear scale: Kp 0–4 (60%), 4–7 (30%), 7–9 (10%)
Independent fallback. The Kp index was invented at GFZ Potsdam in 1932 by Julius Bartels. Uses the Hp30 index — a half-hourly planetary index (30-min resolution) derived from 13 geomagnetic observatories. Same scale as Kp but NOT capped at 9 during extreme storms. Completely independent infrastructure from NOAA. ~30-50 min data latency.
Local time — non-linear scale: Kp 0–4 (60%), 4–7 (30%), 7–9 (10%)
Last-resort fallback. Regional K-index (Kaus) from ~10 Australian magnetometer stations (Darwin, Canberra, Hobart, etc.). Reflects Southern Hemisphere mid-latitude conditions. Completely independent continent, infrastructure, and magnetometer network from NOAA and GFZ.
SWFT's cron worker attempts to fetch Kp data from each source in priority order every 3 minutes. When the primary NOAA Estimated Kp feed responds with valid data, it is stored in the database and used for all dashboard calculations including the GNSS risk model.
If the primary source fails (timeout, HTTP error, or stale data), the cron worker automatically tries the next source in the chain. The NOAA Boulder K-index is the first fallback. GFZ Potsdam Hp30 (30-minute resolution) serves as a completely independent source from a different continent. The Australian BoM K-index provides an independent regional index from the Southern Hemisphere. Finally, the NOAA Kp Forecast is the last resort — its 3-hour granularity means outages may not be reflected for hours.
When a fallback source is active, a blue banner appears at the top of every page indicating
the alternate source in use. All 15-minute Kp values stored in the database include a source column so the origin of each reading is always traceable.