When is it light
in Dayton?
Compare how much daylight you get before and after noon with different clock settings. Change the date, choose a clock time, and explore the Earth all the way down to Dayton’s streets.
Keep today’s twice-a-year changes, keep the summer clock all year (later sunrise and sunset), or keep the winter clock all year (earlier sunrise and sunset). No setting creates extra sunlight.
Each globe shows the same local clock reading, which can represent a different real instant.
Your daylight comparison
Drag to explore · Scroll to zoom · Maps stay linked
Daylight figures always refer to Dayton. Street View links open real Google panoramas in a new tab; their photo lighting does not follow the simulation.
Morning = midnight–noon. Afternoon/evening = noon–midnight. These are full-day totals, not just light elapsed by the chosen time. Twilight is excluded.
It changes when daylight falls on your daily schedule. Permanent daylight time moves sunrise and sunset one hour later on the clock than permanent standard time.
A year of light / 2026
Each column is a local calendar day, from midnight at the top to midnight at the bottom. Purple marks identify skipped or repeated hours; a repeated hour can contain light from either occurrence. Hover for sunrise and sunset. Click to explore a date.
How this model works
All years from 1900 through 2100 use today’s US schedule: advance at 2 AM on the second Sunday in March, reverse at 2 AM on the first Sunday in November. Each transition uses that policy’s own clock. This is a hypothetical comparison using modern rules, not a reconstruction of historical time laws. Permanent daylight time is UTC−4; permanent standard time is UTC−5.
In “same moment” mode, the date and time controls refer to the current Ohio schedule. In “same clock time” mode, each policy interprets those controls using its own clock. The yearly charts always use each policy’s own local calendar days.
Morning and afternoon/evening totals count actual elapsed daylight within that policy’s local calendar date, split at noon. Skipped hours do not count; a repeated hour counts each actual occurrence. Sunrise and sunset describe the solar day nearest noon on the selected clock date. In “same moment” mode, all cards use the same Ohio reference solar day.
“Spring forward” and “fall back” change the clocks in March and November. They are not solstices. The summer solstice is the longest daylight day; the winter solstice is the shortest. The solstice presets use astronomical calculations for the chosen year, converted to the Ohio reference date.
Sunrise and sunset are approximate, calculated for an unobstructed horizon at Dayton’s coordinates with standard refraction. Civil twilight extends to a solar altitude of −6°. The globe uses geometric solar position with a softened day/night boundary; it is a visualization, not a forecast of clouds or weather.
Sources: US daylight saving schedule · US Naval Observatory · SunCalc · Astronomy Engine · CesiumJS. Satellite imagery: Esri, Vantor, Earthstar Geographics, and the GIS User Community. Street maps: © OpenStreetMap contributors. Detailed imagery is current, not historical imagery for the selected year; the Sun position is simulated. No building or terrain shadows are modeled.