- February 13: The Covenant Empire glasses Bliss.
- March 1: Preston Cole's Fleet reaches Harvest and the Second Battle of Harvest begins. It is a human victory, but at an enormous cost. However, the Covenant also claim victory and celebrate through fasting and prayer. The Prophet of Regret televises the executions of "those who failed their duty" at the battle. The Covenant would return to Harvest later in the year, and the UNSC would respond. This led to a five-year long series of engagements on the planet, known by the UNSC as the Harvest Campaign.
- March 10: The WINTER CONTINGENCY protocol is enacted by the UNSC.
- April 26: The Battle of Circinius IV takes place in the Circinius system.
- April 27: The Covenant glasses Circinius IV.
- October 21: Battle of Alpha Aurigae takes place in the Alpha Aurigae System.
- The Type-32 Rapid Assault Vehicle is first observed by the UNSC.