Ionospheric Summary and Forecast

Ionospheric Summary

(last updated 20 May 2026 23:30 UT)

Date T index 20 May 48 Observed Australian Regional MUFs Cocos Island Region: No data available during local day. No data available during local night. Niue Island Region: Depressed by 15% during local day. Depressed by 30% during local night. Northern Australian Region: Near predicted monthly values during local day. Depressed by 20% during local night. Southern Australian Region: Depressed by 15% during local day. Depressed by 20% during local night. Antarctic Region (Casey/Davis/Mawson): Depressed by 20% over the UT day. Monthly T index: Month T index Apr 74 May 71 Jun 68

Ionospheric Forecast

(last updated 20 May 2026 23:30 UT)

Date T index MUFs 21 May 55 Near predicted monthly values/depressed 5 to 15% 22 May 60 Near predicted monthly values/depressed 5 to 15% 23 May 60 Near predicted monthly values/depressed 5 to 15% COMMENT: Maximum Usable Frequencies (MUFs) on UT day were depressed by up to 20% during local night hours and by up to 15% during local day hours in the southern Australian region. Spread-F and sporadic E were observed at Hobart, with milder spread-f observed at Canberra and Perth during local night hours. MUFs are expected to be near predicted monthly values over 21-23 May, with a chance of mild depressions, particularly in the southern Australian region.