12- hour plot of Boulder Magnetometer H- and D components

Period (UTC) 1200-1500 1500-1800 1800-2100 2100-0000
Value
K-index
H-trace
D-trace
K NT
0 2.0
0.9 4.7
2.0 10.5
K NT
0 4.0
2.2 12.2
2.3 13.0
K NT
2 18.6
1.0 5.0
2.9 18.6
K NT

12-hour Boulder-NOAA Magnetometer Monitor
with 3-hourly K-Indices

Final Boulder K-indices are available at Geomagnetic and Solar indices, A/K Indices lists, and the Geophysical Alert Message (WWV)

SWPC Space Weather Alerts for geomagnetic phenomena are based primarily on real-time data from the Boulder-NOAA magnetometer, which is used as a proxy for mid-latitude locations, and as a general indicator of the trend in USAF Planetary K-indices that are not available in real-time.

The geographic location of the Boulder-NOAA geomagnetic observatory is N40.1 W105.2. Magnetometer values are the average of 60 1-second samples. The H component is directed along magnetic north, which is currently about 10 degrees east of geographic north. The D component is pointing 90 degrees clockwise relative to H. This is currently about 10 degrees south of geographic east. For more information see Boulder-NOAA Magnetometer description and The K-index.

This page updates dynamically every minute.

NOAA / Space Weather Prediction Center