Two guests in identical rooms on the same night have often paid very different amounts, and neither was cheated. Hotel rates move daily because the thing being sold cannot be stored.
A room night is perishable inventory
An empty room on Tuesday cannot be sold on Wednesday instead. The revenue for that night disappears at midnight, which makes an unsold room worth nothing rather than something.
That perishability pushes a hotel toward selling at almost any price as the date approaches, provided the rate still covers the cost of cleaning and servicing the room.
The opposite pressure applies months earlier. Selling too much inventory cheaply and too soon leaves nothing for the guests who would have paid far more nearer the date.
Demand is forecast rather than observed
Revenue systems build an expected booking curve for every future date, based on how that day of that week in that season has filled in previous years.
Rates are then set to keep actual bookings tracking the curve. A date running ahead of forecast gets more expensive; a date running behind gets cheaper.
Because the forecast is revised each time a booking arrives or cancels, one night can change price several times in a week while nothing visible happens at the property.
Guests are sorted into segments
A hotel does not sell one rate to everyone. It sells a corporate rate, a group rate, an advance non-refundable rate and a flexible walk-up rate, all for the same physical room.
Each segment behaves differently. Business demand books late and cares about flexibility, while leisure demand books early and cares about price.
Fencing those segments apart with rules about refundability and lead time is how the hotel charges each group closer to what that group will bear.
Group business anchors the calendar
Conferences and weddings are contracted a year or more ahead and take a block of rooms out of circulation at a negotiated rate.
Once a block is committed, the remaining rooms are scarcer, so the rate offered to individual travellers on those dates rises accordingly.
This is why a city can be expensive for reasons a visitor never sees. The event driving the rate may be entirely internal to a convention centre nearby.
Competitors are watched in near real time
Hotels track the published rates of a defined competitive set, usually a handful of properties of similar standard in the same district.
A move by one property is often matched within hours, because a rate that sits visibly above the set loses share on the booking pages where most comparisons happen.
The result is a market that adjusts constantly in small steps, which is why the same room quoted twice in one week rarely returns the same number.