Ionospheric Summary and Forecast
Ionospheric Summary
(last updated 18 May 2026 23:30 UT)
Date T index 18 May 39 Observed Australian Regional MUFs Cocos Island Region: No data available during local day. No data available during local night. Niue Island Region: Depressed by 20% during local day. Depressed by 30% during local night. Northern Australian Region: Near predicted monthly values during local day. Depressed by 25% during local night. Southern Australian Region: Depressed by 15% during local day. Depressed by 30% during local night. Antarctic Region (Casey/Davis/Mawson): Near predicted monthly values over the UT day. Monthly T index: Month T index Apr 74 May 71 Jun 68
Ionospheric Forecast
(last updated 18 May 2026 23:30 UT)
Date T index MUFs 19 May 40 15 to 20% below predicted monthly values 20 May 55 Near predicted monthly values 21 May 65 Near predicted monthly values COMMENT: ASWFC HF Communications Warning 49 was issued on 18 May and is current for 18-19 May. Maximum Usable Frequencies (MUFs) were near predicted monthly values in the northern Australian region during local day, but depressed by 25% during local night. MUFs were depressed by 15-30% in southern Australia over the UT day. Spread-F was observed at Hobart and Canberra during local night hours. MUFs are expected to be 15-20% depressed on 19-May, recovering to near predicted monthly values over 20-21 May.
