Two Dates, Fourteen Days Apart
AGU26 runs 7-11 December 2026 in San Francisco at the George R. Moscone Convention Center, 747 Howard Street, 94103. AGU names 5 November as the last day to register at the early rate. Its housing notice puts the block close on 19 November and adds the qualifier a revenue manager should read twice: bookings may fill before that date.
Both dates are Thursdays. Fourteen days separate them. A delegate who pays the higher rate on 6 November still has thirteen days to take a room inside the block. That gap is the planning window.
The meeting opens Monday 7 December and closes Friday 11 December. The core stay is the nights of Monday 7 through Thursday 10, against a Friday checkout. Registration and housing both opened on 25 August 2026.
What a Delegate Who Misses 5 November Does
The rate steps up after that date. AGU publishes the ladder on its rates page. This pass could not reach that page, so the size of the step is a question for the organiser.
The delegate who misses the deadline carries a shorter runway on lodging. AGU states that it has secured exclusive discounted rates at top-rated, conveniently located hotels, on a first-come, first-served basis.
The Block Holds 44 Properties and Closes 19 November
AGU publishes the block as a numbered hotel map. The key runs 1 to 44, from the Axiom Hotel and the Beacon Grand to The Westin St. Francis and Yotel San Francisco. AGU describes those rates as secured exclusively for attendees.
Forty-four discounted properties on one set of dates puts one buyer in front of 44 suppliers across the Monday-to-Friday week.
A Per-Diem Ceiling Caps Part of the Demand
Part of AGU's audience travels on federal or university funding. The General Services Administration's San Francisco lodging ceiling for December 2026 is $279 a night, excluding taxes, under the fiscal 2027 table. Meals and incidentals run $92 a day, with $69 on the first and last travel day.
A federally funded delegate cannot reimburse above $279 for those nights without another funding source. A rate above that ceiling puts that delegate out of reach at any block rate.
Two Block Hotels Are Also Programme Venues
AGU states that some events and sessions will also take place at the San Francisco Marriott Marquis, 780 Mission Street, and at InterContinental San Francisco, 888 Howard Street. Both sit on the block key, at 33 and 28.
Programme traffic moves between those two buildings and the convention centre, so a delegate on foot weighs both hardest.
Four Terms to Get in Writing Before 19 November
AGU26 publishes the deadline, the key and the first-come rule. It publishes no nightly rate, deposit schedule, cancellation window or attrition clause on any page this pass could read. Ask the housing provider for four terms in writing: the date inventory releases, the rate the property charges after release, the penalty and attrition terms, and whether a government per-diem rate can be loaded alongside the block rate.
Maritz is the vendor AGU names as official for AGU26 registration and housing, so those answers come from the housing desk.
What the Block Does to Direct-Booking Leverage
Inside the block the lever is inventory. Forty-four properties at one negotiated band leaves a delegate comparing streets, and the first-come rule makes the room the scarce good. Holding the block rate and releasing inventory to the property's own channels after the close protects both.
Outside the block the lever is the calendar. The 19 November close leaves the December dates to whatever demand did not clear the block, including every delegate who registered after 5 November. Diarise both dates. That fourteen-day window is when the late registrant is still choosing, and still inside the block.
A hotelhuddle request reaches 50 or more hotels in the city in one submission, hotels respond in 24 to 72 hours, submission is free, and the group pays the property directly with no markup added to the rate.
The Date to Confirm, and the Contact
AGU's annual-meeting page and its education section carry two readings of the early-rate close: 5 November and 6 November. Confirm the day when the booking is made.
The Member Service Center takes registration and housing questions at service@agu.org, 800.966.2481 toll-free in North America and +1 202.462.6900. Press registration is complimentary, and press delegates book inside the same 44-property block on the same 19 November close.