Clerk of the Course Gary Thompson made the decision following consultation with several leading competitors who completed an inspection lap of the Mountain Course.
Michael Dunlop, the record 33-time TT winner, did not participate in the lap.
The Senior race was cancelled for the first time in 2012 due to bad weather.
Other cancellations were due to the World Wars, Foot and Mouth disease in 2001 and the Covid pandemic in 2020 and 2021.
5. John McGuinness (Honda Racing UK) on the course inspection lap at Ballagarey on Saturday evening.
Callum Staley/Pacemaker Press Photo: Callum Staley/Pacemaker Press
6. An emotional John McGuinness with Honda Racing team boss Havier Beltran after it was announced the 2025 Senior TT was being cancelled on Saturday.
Stephen Davison/Pacemaker Press Photo: Stephen Davison/Pacemaker Press
7. Dominic Herbertson HRRC/Adam Hewitt Ltd Honda on the course inspection lap at Ballagarey on Saturday.
Callum Staley/Pacemaker Press Photo: Callum Staley/Pacemaker Press