From Halopedia, the Halo wiki
- February 13: The outer colony of Bliss is glassed by the Covenant.
- February 24: Doctor Catherine Halsey makes an entry in her personal journal in which she ponders the nature of the Covenant and the relationships between its client species.
- March 1: Preston Cole's Battle Group X-Ray reaches Harvest and the Second Battle of Harvest begins, achieving a Pyrrhic victory. However, the Covenant also claim victory and celebrate through fasting and prayer. The Prophet of Regret broadcasts the executions of "those who failed their duty" in the battle. The Covenant return to Harvest later in the year, leading to a five-year campaign for control of the planet.
- March 4: The Razor-class prowler UNSC Starry Night covertly observes the CAR-class frigate Radiant Arrow and its complement of Type-27 Banshees at the planet Netherop.
- March 5: Twelve Spartan-IIs of Blue, Green, and Gold Teams infiltrate the Radiant Arrow in high equatorial orbit over Netherop. The frigate is intentionally scuttled by its shipmaster but all Spartans make it off in time.
- March 7: Staff Sergeant Avery Johnson meets with Admirals Preston Cole and Michael Stanforth and Doctor Catherine Halsey aboard the UNSC Everest and agrees to be recruited for Operation: SILENT STORM.
- March 8: The particulars of Operation: SILENT STORM are formalized aboard the Point Blank-class stealth cruiser UNSC Vanishing Point.
- March 10: The WINTER CONTINGENCY protocol is enacted by the UNSC.
- March 23: Insurrectionists bomb civilian spaceport in Troisi City, Lodestone.
- April 2: UNSC forces working with ONI agents prevent an attack on New Harmony, Mars. Two Insurrectionists, Christina Rice and James McCann, were disguised as Army specialists and were stealing weapons for a possible attack.
- April 2: Intersystem News publishes
- April 26: The Battle of Circinius IV takes place: the Covenant launch an assault on Circinius IV, killing almost the entire human population of the planet. SPARTAN-II Blue Team is deployed to retrieve survivors from Corbulo Academy of Military Science; only four cadets from Hastati Squad remain alive after the initial assault, three of whom make it to the extraction point and evacuate as the planet is glassed.
- April 28: Vice Admiral Michael Stanforth requested for the Office of Naval Intelligence to repurpose all assets to aid the war against the Covenant and to refocus all research on wartime strategy.
- May 3: Dr. Catherine Halsey devises a new matrix strata with random-access couplers that could theoretically expand an AI's lifespan. Those protocols are authorized by Vice Admiral Michael Stanforth some time later.
- May 30: The Covenant attacks the human colony Mesra, on Qusdar system. Blue Team is deployed on the planet.
- By June, FLEETCOM is unable to consolidate battlefield intelligence before it became inactionable, and stops trying to coordinate core strategy, granting operational autonomy to each battle group.
- The Type-32 Rapid Assault Vehicle is first observed by the UNSC.
- Biko is glassed by the Covenant.
- The Committee of Minds for Security analyze the Covenant's glassing capabilities based on recorded data from prior engagements. They also discuss changing the primary focus of the UNSC Special Forces, with the protection of infrastructure, previously the main focus of the Spartan-IIs, being shifted to the ODST. Later in the year the Committee discuss the possibility of a hypothetical Covenant counterpart to the Assembly and the possibility of contacting it.
- Dr. Halsey's personal journal, additional materials
- Dr. Halsey's personal journal, February 24, 2526
- Halo: Silent Storm, Chapter 1
- Halo: Silent Storm, Chapter 3
- Halo: Silent Storm, Chapter 9
- Halo: Silent Storm, Chapter 4
- Halo: Silent Storm, Chapter 5
- Bungie.net: CAA FACTBOOK/UNSC Operational Reports-Γ
- Halo 4: Forward Unto Dawn, Part 1
- Halo 4: Forward Unto Dawn
- Halo Waypoint Forums - Today in Halo
- Halo: Reach, Dr. Halsey's personal journal
- Halo: Oblivion - Chapter 1
- Halo Waypoint: Ghost
- Halo: Reach, Data pad 10
- Halo: Reach, Data pad 11
- Halo: Reach, Data pad 12