Hotel rates move for the same reasons airline fares do, with an extra layer of distribution costs.
Revenue management
Rates adjusted continuously based on occupancy and demand forecasts.
Which is why the same room costs different amounts on different days.
Booking platform commission
Intermediaries taking a substantial share.
Which is why hotels push direct booking.
Rate parity clauses
Agreements preventing hotels undercutting platforms.
Which regulators in several countries have restricted.
Cancellation policies
Cheaper rates carrying stricter terms.
Which is the actual trade.
Why direct booking is pushed so hard
Booking platform commissions take a substantial share of the room rate, and hotels keep all of a direct booking.
Which is why loyalty schemes, free breakfast and best-rate guarantees are offered for booking on the hotel's own site.
The commission is generally invisible to the guest and is one of the largest costs a hotel carries on each room sold through a platform.
Rate parity and its erosion
Clauses preventing hotels from offering lower prices elsewhere.
Which competition authorities in several countries have restricted or banned.
Length of stay pricing
Rates varying with how many nights are booked.
Which reflects turnover cost and demand shape.
Group and corporate rates
Negotiated pricing outside public rates.
Practical approach
Compare on a platform and then check the hotel directly.
Why the same room varies so much
Occupancy forecasts, local events, day of week, season and how far ahead the booking is made all feed into the rate.
Which means a price that looks arbitrary is the output of a model rather than a decision about you.
Hotels near a venue hosting a major event will price accordingly, and that is visible months ahead if you look.
Loyalty programmes
Points, upgrades and status benefits.
Which are worth more to frequent travellers than to occasional ones.
Resort and facility fees
Mandatory charges added to the advertised rate.
Which regulators in several jurisdictions have acted against.
Reviews and their influence
Ratings affecting bookings substantially.
Which is why hotels solicit them.
Practical points
Check total cost including all mandatory charges before comparing.
Booking sensibly
Compare on a platform to find candidates, then check the hotel's own site for the same dates, and compare total cost including every mandatory charge.
Which frequently produces a better rate or better terms for the same money.
Free cancellation rates cost more and are worth it whenever plans could change, because the difference is usually smaller than the amount at risk.
Timing
No reliable rule about when to book.
Which is the same conclusion as for flights and for the same reasons.
Alternative accommodation
Short-term rentals with different cost structures and regulation.
Which several cities have restricted.
Overbooking
Hotels occasionally relocating guests.
Which carries obligations in many jurisdictions.
Complaints
Raising issues during the stay rather than afterwards.
The pattern that recurs
Across almost all of these systems, the same three things turn out to be true. The behaviour that looks irrational from outside is optimising for something the observer cannot see. The cost that seems unexplained is usually concentrated in one specific stage of the process. And the information that would resolve the confusion is generally published somewhere and read by nobody.
That last point is the most useful. Regulators, operators and industry bodies publish an enormous amount of explanatory material that answers exactly the questions people complain about not being able to get answers to. It is dry, it is not promoted, and it is free.
A note on sources
Where regulation is involved, national regulators publish the actual rules and they are generally clearer than press coverage of them. Where an industry is involved, trade publications aimed at people working in it are considerably more informative than consumer coverage.
Practices described here vary substantially between countries, and anything with legal, financial or medical consequences warrants checking against the rules that apply where you are.
What to do with any of this
Very little of it changes a decision on its own. What it changes is the ability to ask a better question: of a company, of a service, of a regulator, or of yourself before assuming that something went wrong.
Why it is worth knowing how these things work
Most of the systems that shape ordinary life are invisible by design. Nobody explains why a parcel took an odd route, why a price changed between two searches, or why a wait extended.
The absence of explanation is rarely deliberate concealment. It is that the people running these systems are solving their own problems, and the reasoning behind their decisions is obvious to them and completely opaque from outside. Understanding the mechanism does not always change what you can do about it, and it does remove a category of frustration that comes from assuming something is arbitrary when it is not.
Where to read further
Trade publications written for people working in an industry are consistently the most informative public source on how it operates, and most of them are freely readable.
They assume knowledge that general coverage explains and skip the framing that general coverage adds, which makes them harder to start with and considerably more useful once you do.