The hour a World Cup match kicks off looks arbitrary until the broadcast map is laid over it. Scheduling is largely an exercise in serving distant audiences.
The paying audience is mostly elsewhere
Broadcast rights sold across Europe, Asia, Africa and the Americas account for a substantial share of a tournament's revenue, far more than ticket sales.
Those buyers want matches in their own evening viewing hours, which for a tournament held in the Americas means kickoffs in the local morning or early afternoon.
The result is a schedule that appears strange to spectators in the stadium but sensible in the markets where most of the money originates.
A host spanning many time zones complicates it further
A tournament staged across a continent-sized area has host cities several hours apart, so a single national broadcast window covers very different local hours.
An afternoon slot on one coast is late morning on the other, and organizers assign fixtures to venues partly to keep that spread manageable.
The same problem affects the teams, whose travel between matches can cross more time zones than an entire European tournament would require.
Heat is the constraint pushing the other way
Midday summer kickoffs in warm host cities create conditions that slow the game and raise medical risk for players.
Cooling breaks part-way through each half are the standard response, and their timing depends on measured conditions rather than a fixed schedule.
Venue choice absorbs some of this too, with roofed or air-conditioned stadiums able to take slots that an open bowl in the same region could not.
Group stages and knockouts follow different rules
During the group stage, several matches happen each day and the schedule is built to avoid direct clashes in major markets.
The final round of group fixtures removes that freedom, because matches in the same group must start at the same moment to prevent teams knowing what result suits them.
Knockout rounds are sparser, so each fixture can be placed in the strongest available broadcast window without competing against another match.
What this means for a domestic viewer
Fans in a host nation often get the least convenient times of anyone, watching their own tournament during working hours.
Understanding why removes the mystery: the schedule was optimized for people who will never enter the stadium, and the local audience was assumed to attend rather than watch from home.
The practical consequence for anyone planning around the tournament is that the fixture list has to be read alongside a time zone map, because the published local start times vary from city to city within the same round.