Why the first two meters from the window matter most
Daylight falls off quickly as you move away from a window, so the desk you choose changes what your body clock actually receives. In field measurements and annual simulations of offices, desks within roughly 2 meters of the window were the ones able to meet circadian light targets from daylight; desks further in did not reliably get there [1]. The practical reading is that proximity to the glass, not just the size of the window, decides whether daylight alone is enough to signal "daytime" to your body.
This is a threshold effect rather than a smooth gradient you can ignore. A desk just inside the 2-meter band behaves more like a window seat than like a desk in the middle of the floor [1]. That makes desk assignment a circadian decision, not only a matter of view or draft.
Orientation and season change how much light arrives, and when
Which way a window faces changes the daylight a desk receives across the year, which is why the same desk can look bright in one season and dim in another. The office study compared rooms with different window orientations and modeled light across the full year, treating orientation as a factor in circadian exposure rather than a fixed backdrop [1].
Season enters through both sky conditions and sun position. Simulations and real-time office experiments that varied seasonal conditions and sky type found circadian stimulus changing with them, including cases where an occupant faced an open east-oriented window [2]. In plain terms, a desk's circadian dose is a moving target: the same spot can be adequate in one part of the year and marginal in another [1][2].
Blinds can cancel a good desk position
A close desk only helps if the daylight is allowed in. Experiments with controlled venetian blinds in office settings found that circadian stimulus dropped when blinds were deployed, compared with the same setup with the window uncovered [2]. That means the 2-meter advantage measured with daylight available [1] is conditional: close to the window with blinds down can deliver less circadian light than the distance alone would suggest.
The two effects compound. Distance sets the ceiling on how much daylight can reach you, and blinds decide how much of that ceiling you actually get [1][2]. A worker who closes blinds against glare in the afternoon may be trading away the very signal that keeps their body clock aligned.
What this means for choosing and adjusting a workstation
If circadian light is the goal, the priority order is distance first, then whether the blinds stay open, then orientation and season as the backdrop that decides how much margin you have [1][2]. A desk within about 2 meters of an open window has the best chance of meeting circadian targets from daylight alone; a deeper desk should not be assumed to do so [1].
Two gaps are worth naming beside these conclusions. The office study did not examine blinds or seasonal variation, so its distance finding describes daylight potential rather than what a worker with closed blinds experiences [1]. The blind experiments did not isolate desk distance, orientation, or season, so their result describes the effect of blind position within a given setup rather than a full map of every combination [2]. Together the evidence supports the direction of each factor but not a precise formula for any single desk.
Sources used in this answer
Analysis of integrative lighting through field measurements and annual daylight simulations in offices
In office field measurements and annual simulations, desks within about 2 meters of the window could meet circadian light targets from daylight, and window orientation affected circadian exposure, while blinds and seasonal variation were not addressed.
Real-time investigations and simulation on the impact of lighting ambience on circadian stimulus
Office simulations and real-time experiments found circadian stimulus varied with seasonal and sky conditions and decreased when controlled venetian blinds were used, without isolating desk distance, orientation, or season.