Light Switch utility

Light Switch is a PowerToys utility that automatically switches your Windows theme between light and dark modes based on time of day. You can configure Light Switch to change themes automatically using sunrise and sunset times in your location, or set custom schedules that work best for your daily routine.

Benefits of using Light Switch include:

• Reduced eye strain - Dark themes are easier on your eyes in low-light environments
• Better battery life - Dark themes can help extend battery life on devices with OLED displays
• Automatic adaptation - No need to manually change themes throughout the day

How to activate and use Light Switch

Light Switch can be activated or deactivated by opening PowerToys Settings and changing the Enable Light Switch toggle. You can then configure the settings to specify the times for switching between light and dark themes based on your local sunrise and sunset times or manually set times.

The following settings are available for Light Switch:

Setting	Description
Enable Light Switch	Turn the Light Switch utility on or off.
Theme toggle shortcut	Set a keyboard shortcut to manually toggle between light and dark themes.
Schedule Mode	Choose between using dark mode from Sunset to Sunrise (based on your location), Fixed hours (set specific times), or Follow Night Light (synchronize with the Windows Night Light schedule). Note that you must have location services enabled and synced for the Sunset to Sunrise mode to work. You can also disable the schedule by using the Off mode while still having access to the shortcut to toggle your theme.
Location	Enter your coordinates manually or use location services to automatically switch between light and dark mode based on local sunrise and sunset times.
Offset in minutes	Adjust the time for switching themes by a specified number of minutes before or after sunrise and sunset.
Turn on dark mode	Set the time to switch to dark mode when using manual mode.
Turn on light mode	Set the time to switch to light mode when using manual mode.
Apply dark mode to	Choose whether Light Switch applies dark mode to System (Taskbar, Start, and other system UI) and/or Apps (supported apps).
Apply monitor settings to	When the Power Display utility is enabled, choose a Power Display profile to apply when Light Switch transitions Windows into Dark mode profile and a profile to apply when it transitions to Light mode profile. This makes your saved monitor brightness, contrast, and color temperature settings switch automatically with the system theme.

Command-line interface

Light Switch includes a command-line interface that controls the running Light Switch service, so you can check or change the theme from scripts and terminals. PowerToys adds its bin folder to your PATH, so you can run PowerToys.LightSwitch.CLI.exe from any folder in Windows Terminal, PowerShell, or Command Prompt. If a terminal was already open when you installed PowerToys, open a new one so it picks up the updated PATH.

Light Switch must be enabled in PowerToys and its service must be running. The CLI doesn't start PowerToys or turn on Light Switch for you.

Command	Description
status	Show the current system and app themes, which theme targets Light Switch changes, the schedule mode, and whether a manual override is active.
light	Apply the light theme to the targets selected in Apply dark mode to (System, Apps, or both).
dark	Apply the dark theme to the selected targets.
toggle	Toggle the selected targets between light and dark, the same as the Theme toggle shortcut.
schedule enable [--mode <mode>]	Turn on scheduling. Use --mode with fixed-hours, sunset-to-sunrise, or follow-night-light to choose the schedule.
schedule disable	Turn off scheduling by setting the schedule mode to Off.

Option	Description
--json	Write a single JSON object, including for errors.
-h, --help	Show help. Doesn't contact the service.
--version	Show the CLI version. Doesn't contact the service.

When light, dark, or toggle sets a theme that's different from what the schedule calls for, Light Switch keeps that theme as a manual override until the next scheduled change or until you change a relevant setting.

schedule enable --mode uses the times, location, and offsets already saved in Light Switch settings. If you omit --mode, the command succeeds when a schedule is already on. If the schedule mode is Off, the command fails and asks you to specify a mode.

Usage example

# Check the current theme and schedule state
PowerToys.LightSwitch.CLI.exe status

# Switch the configured targets to dark mode
PowerToys.LightSwitch.CLI.exe dark

# Turn on the sunset-to-sunrise schedule
PowerToys.LightSwitch.CLI.exe schedule enable --mode sunset-to-sunrise

# Get the current state as JSON
PowerToys.LightSwitch.CLI.exe status --json

With --json, the output contains a version, a success value, and either a state object or an error object with a code and message. For example:

{"version":1,"success":true,"state":{"systemTheme":"dark","appsTheme":"dark","changeSystem":true,"changeApps":true,"scheduleMode":"FixedHours","manualOverride":true}}

The CLI returns the following exit codes:

Exit code	Meaning
0	Success.
1	The command failed, the theme couldn't be read or changed, or the service returned an unexpected response.
2	Invalid arguments or configuration.
3	The Light Switch service isn't available. Turn on Light Switch in PowerToys and try again.
4	The command timed out or the connection to the service was lost. The change might still have been applied, so run status before you try again.

The CLI never retries a command that changes the theme or schedule automatically.

Install PowerToys

This utility is part of the Microsoft PowerToys utilities for power users. It provides a set of useful utilities to tune and streamline your Windows experience for greater productivity. To install PowerToys, see Installing PowerToys.