Day & Night Cycle - Drop-in System v1.0

Overview

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A drop-in day/night cycle for any Roblox game. 6 themed presets (Realistic / Fantasy / Horror / Tropical / Arctic / Cyberpunk), four-phase color blending across every Lighting + Atmosphere + ColorCorrection property, auto-replicated time, an optional clock widget with phase-tinted dot, boundary hooks for Dawn / Noon / Dusk / Midnight, and a runtime API for cutscenes and time-of-day game logic.

Set RealSecondsPerDay and ship. The cycle handles everything else — sun position, sky color, fog, atmosphere, color grading.

Open source. Plain Luau. No obfuscation. Edit any file freely.

The Cycle

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4-Phase Color Blending

• Dawn — sunrise warmth, soft amber ambient, clearing fog
• Day — peak brightness, blue-shifted sky, low fog
• Dusk — sunset crimson, warm horizon, increasing fog
• Night — deep indigo, cool ambient, dense atmospheric haze
• Smooth interpolation every tick — no popping, no jarring transitions
• 20Hz update rate by default (UpdateInterval = 0.05) — buttery smooth, costs nothing on a server

6 Themed Presets

• Realistic — earth-like blue sky, golden sun, navy night with star-blue tint (default — fits 90% of games)
• Fantasy — pastel violets, rose horizons, magical cyan-purple haze (RPG · fairy · mystic)
• Horror — permanent overcast gloom, blood-tinted dusk, crushing dark night with thick fog
• Tropical — saturated golden sun, turquoise sky, vivid orange sunsets (beach · island · summer)
• Arctic — pale blue sun, ice-white horizons, aurora-tinted nights (snow · winter biomes)
• Cyberpunk — magenta sun, electric pink dusk, neon-glow night with deep purple haze (sci-fi · synthwave)
• Custom — hand-tune every value via Config.CustomPhases

What Gets Wired

• Lighting.ClockTime — drives Roblox's built-in sun/moon, replicates to all clients automatically
• Brightness · Ambient · OutdoorAmbient · ColorShift_Top/Bottom — base sky lighting
• FogStart · FogEnd · FogColor — atmospheric depth per phase
• Atmosphere instance — auto-creates if missing, blends Density / Color / Decay / Glare / Haze
• ColorCorrectionEffect — auto-creates if missing, blends Brightness / Contrast / Saturation / TintColor
• Per-layer toggles — disable any layer (WireFog, WireAtmosphere, etc.) if your game already handles it

The Clock Widget

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• 3 display formats — "24h" (default), "12h" (with AM/PM), "phase" (just "Dawn" / "Day" / "Dusk" / "Night")
• Phase-tinted dot — colored dot on the left interpolates through the four phase tints; glanceable mood indicator
• Pure scale sizing — UDim2.fromScale + Min/Max pixel clamps, looks identical on every device
• Mobile auto-position — relocates on phone-only devices to avoid Roblox's jump button area
• Configurable everything — position, anchor, size, font, colors, border, corner radius, transparency
• Disable in one line — Config.ClockWidget.Show = false
• No remotes needed — reads Lighting.ClockTime directly (replicated by Roblox automatically)

Boundary Hooks

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Wire game logic to time of day. Each callback fires exactly once per phase crossing.

• Hooks.OnDawn(prevHour, newHour) — shopkeepers wake, daytime mobs spawn, vampires retreat
• Hooks.OnNoon(prevHour, newHour) — midday market refresh, lunch buffs, sun magic peak
• Hooks.OnDusk(prevHour, newHour) — light lanterns, spawn nightly mobs, lock daytime shops
• Hooks.OnMidnight(prevHour, newHour) — daily reset, witching hour bosses, midnight events
• Bracket-crossing detection — fires correctly even when _G.CoreShunDayNight_SetTime skips a phase
• Server-side — fire RemoteEvents from inside the hook for client-side reactions

Runtime API (_G Hooks)

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Reading:

• _G.CoreShunDayNight_GetTime() — current in-game hour 0..24
• _G.CoreShunDayNight_GetPhase() — "Dawn" / "Day" / "Dusk" / "Night"
• _G.CoreShunDayNight_GetSpeed() — current speed multiplier
• _G.CoreShunDayNight_IsPaused() — boolean

Writing (server-side):

• _G.CoreShunDayNight_SetTime(hour) — jump to that hour, fire boundary hooks crossed
• _G.CoreShunDayNight_SetSpeed(mult) — speed multiplier (1.0 = normal); useful for "time potion" or cutscenes
• _G.CoreShunDayNight_Pause() — freeze the cycle in place
• _G.CoreShunDayNight_Resume() — unfreeze the cycle
• _G.CoreShunDayNight_AdvanceMinutes(n) — jump n in-game minutes forward

Configurable Cycle

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• RealSecondsPerDay — 1800 (30 min) is the sweet spot. 600 for arcade-fast. 3600 for realistic. 86400 to map in-game time to real time.
• StartingTime — boot at 06:00 (default), or set to 12:00 for daytime-start, 0:00 for midnight-start
• StartPaused — boot frozen at StartingTime; resume on any trigger you want
• SkipNight — fast-forward through nighttime hours if your game is daytime-only
• UpdateInterval — default 0.05 (20Hz). Bump to 0.1 for very large servers if you want to halve the work.
• DawnHour / NoonHour / DuskHour / MidnightHour — move phase boundaries. Want longer nights? DawnHour=8 + DuskHour=16.

Custom Presets

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Adding your own preset takes about 5 lines.

Open DayNightPresets.lua, append a new entry to Presets with Dawn / Day / Dusk / Night tables (Brightness, Ambient, OutdoorAmbient, ColorShift, Fog, nested Atmosphere, nested ColorCorrection). Then set Theme.Preset = "MyPalette" in DayNightConfig.lua.

All numeric fields interpolate linearly. Color3s use Color3:Lerp. Nested tables interpolate field-by-field.

Pairs Well With

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• Quest System — time-locked quests via _G.CoreShunDayNight_GetPhase() in CanAccept predicates; spawn nightly quest mobs in OnDusk
• Music Player — swap to a "night" playlist on OnDusk, back to "day" on OnDawn; massive mood shift for free
• Toast — fire _G.CoreShunToast_Show("Night falls...", "info") inside OnDusk so players notice the shift
• Settings Menu — expose a "skip night" toggle that flips Config.Cycle.SkipNight at runtime

Cross-Platform

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• Desktop — clock widget renders top-right by default
• Mobile — clock widget auto-relocates to a touch-safe position on phone-only devices
• Console — same widget, no input needed
• Replicated for free — server writes Lighting.ClockTime, all clients read it; no RemoteEvents, no drift

What's Included

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• CoreShunDayNightCycle.rbxmx — the full system (drop into Workspace + run installer)
• DayNightConfig.lua — single config ModuleScript (the only file you edit)
• DayNightPresets.lua — 6 themed palettes (extensible)
• DayNightServer.lua — cycle loop + phase blending + atmosphere wiring + boundary hooks
• DayNightClient.lua — optional on-screen clock widget
• Installer.lua — one-click command bar installer
• Manual.pdf — comprehensive feature guide
• Cheatsheet.pdf — visual quick-reference
• README.txt — setup + reference
• Rojo project — for active development

Easy Installation

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1. Drag CoreShunDayNightCycle.rbxmx into your place
2. Open the Studio Command Bar
3. Run require(workspace.CoreShunDayNightCycle.Installer)
4. Open DayNightConfig in ReplicatedStorage and pick a preset (or skip — Realistic is default)
5. Press F5 — the cycle starts at 06:00, completes a full day in 30 minutes. The clock widget appears top-right.

Frequently Asked

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How long is one in-game day?
30 real minutes by default. Edit Config.Cycle.RealSecondsPerDay — 1800 = 30 min, 600 = 10 min, 3600 = 1 hour, 86400 = 24 hours (real-time).

My game already has a custom Atmosphere — will it conflict?
Set Config.Wiring.WireAtmosphere = false. The cycle will leave your Atmosphere alone. Same for Fog (WireFog = false) and ColorCorrection (WireColorCorrection = false).

How do I freeze the cycle at sunset for a screenshot?
_G.CoreShunDayNight_SetTime(18); _G.CoreShunDayNight_Pause(). Resume with Resume().

How do I make night last longer than day?
Edit Config.Phases. Default is symmetric (DawnHour=6, DuskHour=18 — 12 hrs each). For 8 hours of day and 16 hours of night, set DawnHour=8 + DuskHour=16. Blending handles non-uniform spacing.

Can I add my own preset?
Yes. Open DayNightPresets.lua and append a new entry with Dawn / Day / Dusk / Night tables. Then set Theme.Preset = "MyPalette". About 5 lines.

Does the cycle persist across rejoin?
The cycle is per-server. New servers always start at StartingTime. If you want game-wide synced time, store the start time in MemoryStoreService and set StartingTime dynamically before requiring the system.

How does the clock widget know the time without a remote?
The server writes Lighting.ClockTime every tick. Roblox replicates Lighting properties to all clients automatically. The client reads Lighting.ClockTime directly — no RemoteEvent, no drift.

Will it conflict with other systems that touch Lighting?
Use the wiring flags. If another system handles Fog, set WireFog = false. The cycle only touches the layers you opt in to.

Can I disable the clock widget entirely?
Yes — set Config.ClockWidget.Show = false. The cycle still runs in the background; you just won't see the on-screen clock.

Open source?
Fully. Plain Luau, no obfuscation. Edit any file to customize.

More Tools by coreshun

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• In-Game Systems — Quest System, Settings Menu, Music Player (premium), Simple Music Player, Daily Rewards, Loading Screen, Advanced Chat System, Toast, Anti-Exploit, AutoRejoin, Codes Redemption
• Studio Plugins — Color Picker, UI Wireframe, Gamepass Manager, TODO Tracker (free)
• Bundles — up to 45% off

Browse all: builtbybit.com/creators/coreshun

Support

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Discord: discord.com/invite/hdB5tadkk8