Activity map
The map shows the latest value of the index at all stations. The colour of the circles are set by the highest threshold exceeded; blue means that no threshold is exceeded. The sizes of the circles are proportional to the value of R at the location relative to the largest R on the map at the moment. The lower threshold (yellow) corresponds to a 50 % probability of weak auroras and the upper threshold (red) corresponds to a 50 % probability of strong auroras.
Bar graph
The bar graph shows the R-index as a timeseries for the latest 24 hours. The thresholds are shown as horizontal lines. The colour of each bar is set by the highest threshold that the index exceeds. The lower threshold (yellow) corresponds to a 50 % probability of weak auroras and the upper threshold (red) corresponds to a 50 % probability of strong auroras. You can change the magnetometer station shown from the drop-down menu above the graph.