Otter Tail Corporation

Item 5.02 Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers. On August 28, 2026, Thomas J. Webb notified Otter Tail Corporation (the “Company”) of his intention to not stand for reelection and instead retire from the Company’s Board of Directors effective at the conclusion of his current term, which expires at the time of the 2027 Annual Meeting of Shareholders, in accordance with the Corporation’s director retirement policy. Mr. Webb’s decision to not stand for reelection is not the result of any disagreement with the Company’s operations, policies or procedures. On August 31, 2026, Kathryn O. Johnson notified the Company of her intention to not stand for reelection and instead retire from the Company’s Board of Directors effective at the conclusion of her current term, which expires at the time of the 2027 Annual Meeting of Shareholders, having reached retirement age in accordance with the Corporation’s director retirement policy. Dr. Johnson’s decision to not stand for reelection is not the result of any disagreement with the Company’s operations, policies or procedures.