Apr-Jun
Apr-Jun
Jan-
Apr
Jun-Aug
May-Aug
Jul-Sep
May-
Jun
Aug
May-Jul
May-Jul
May-Jul
May-
Jul
Apr-Jun
Jun-Aug
May-Jul
May-Jul
Apr-Jun
Apr-Jun
May-
Jul
Apr-Jun
Apr-
Jun
Mar-
May
Mar-
May
Nov
Mar-
May
Nov
Mar-
May
Nov
May-
Jul
Jun-
Aug
Apr-
Jun
Apr-
Jun
Apr-Jun
Mar-May
Mar-
May
May-Jul
Apr-
Jun
Mar-
May
Mar-Jun
Apr-Jul
May-
Jul
Jun-Aug
Jun-
Aug
Jun-Aug
Jun-Aug
Jun-Aug
Jun-Aug
Aug
Jun-Aug
May-Jul
Jun-Aug
Apr-Jun-Jul
Peak Frequency
NSSL Annual Cycle