Weather and Time Sync in FiveM

Weather and time synced across servers creates a shared experience and atmosphere that makes RP more interesting.

Basic Time Sync

-- server.lua
local serverTime = { hour = 12, minute = 0 }
local TIME_MULTIPLIER = 2 -- time is 2x faster than actual time

Citizen.CreateThread(function()
    while true do
        Citizen.Wait(30000) -- updated every 30 seconds realtime
        
        serverTime.minute = serverTime.minute + (TIME_MULTIPLIER)
        if serverTime.minute >= 60 then
            serverTime.minute = serverTime.minute - 60
            serverTime.hour = serverTime.hour + 1
        end
        if serverTime.hour >= 24 then
            serverTime.hour = 0
        end
        
        -- Broadcast to everyone
        TriggerClientEvent('weather:syncTime', -1, serverTime.hour, serverTime.minute)
    end
end)

-- Send time to the player who just joined.
AddEventHandler('playerJoining', function()
    Citizen.SetTimeout(3000, function()
        TriggerClientEvent('weather:syncTime', source, serverTime.hour, serverTime.minute)
    end)
end)

-- client.lua
RegisterNetEvent('weather:syncTime')
AddEventHandler('weather:syncTime', function(hour, minute)
    NetworkOverrideClockTime(hour, minute, 0)
end)

Dynamic Weather System

-- server.lua
local weatherTypes = {
    'EXTRASUNNY', 'CLEAR', 'CLOUDS', 'SMOG',
    'FOGGY', 'OVERCAST', 'RAIN', 'THUNDER',
    'CLEARING', 'NEUTRAL', 'SNOW', 'BLIZZARD'
}

local currentWeather = 'CLEAR'
local nextWeather = 'CLEAR'
local weatherTransition = false

-- Change weather randomly every 15-45 minutes.
local function ScheduleWeatherChange()
    local delay = math.random(15, 45) * 60 * 1000
    Citizen.SetTimeout(delay, function()
        -- Select new weather (bias towards weather that makes sense)
        local weights = {
            EXTRASUNNY = 15, CLEAR = 25, CLOUDS = 20,
            OVERCAST = 15, RAIN = 15, THUNDER = 5,
            FOGGY = 5
        }
        
        local total = 0
        for _, w in pairs(weights) do total = total + w end
        
        local roll = math.random(total)
        local cumulative = 0
        for weather, weight in pairs(weights) do
            cumulative = cumulative + weight
            if roll <= cumulative then
                nextWeather = weather
                break
            end
        end
        
        TriggerClientEvent('weather:change', -1, nextWeather)
        currentWeather = nextWeather
        
        ScheduleWeatherChange() -- schedule next time
    end)
end

ScheduleWeatherChange() -- start loop

-- client.lua
local currentWeather = 'CLEAR'

RegisterNetEvent('weather:change')
AddEventHandler('weather:change', function(weather)
    -- smooth transition
    SetWeatherTypeOvertimePersist(weather, 30.0) -- Change in 30 seconds.
    currentWeather = weather
    
    -- Notify the player
    local weatherLabels = {
        CLEAR = 'clear sky',
        RAIN = 'Rain',
        THUNDER = 'thunderstorm',
        SNOW = 'It's falling snow',
        FOGGY = 'thick fog'
    }
    
    if weatherLabels[weather] then
        exports['M2.Notify']:Notify('info', 'Weather: ' .. weatherLabels[weather], 4000)
    end
end)

Season System

-- server.lua
local seasons = {
    { name = 'Summer', weatherWeights = { EXTRASUNNY = 40, CLEAR = 40, RAIN = 20 } },
    { name = 'rainy season', weatherWeights = { RAIN = 40, THUNDER = 20, OVERCAST = 40 } },
{ name = 'Winter', weatherWeights = { CLOUDS = 30, FOGGY = 30, CLEAR = 40 } }
}

local currentSeason = 1

-- Change season every 7 days real-time
local SEASON_DURATION = 7 * 24 * 60 * 60 * 1000

Citizen.SetTimeout(SEASON_DURATION, function()
    currentSeason = (currentSeason % #seasons) + 1
    TriggerClientEvent('weather:season', -1, seasons[currentSeason].name)
end)

Blackout System (Event)

-- Server: Turn on/off lights in the entire city.
RegisterCommand('blackout', function(source, args)
    if not IsPlayerAceAllowed(tostring(source), 'admin') then return end
    
    local state = args[1] == 'on'
    TriggerClientEvent('weather:blackout', -1, state)
end, false)

-- Client
RegisterNetEvent('weather:blackout')
AddEventHandler('weather:blackout', function(state)
    SetArtificialLightsState(state) -- Turn off/on street lights.
    SetArtificialLightsStateAffectsVehicles(state)
end)

Summary

Good weather and time sync create a shared world where players can live together. Dynamic weather increases unpredictability. That makes every gameplay session different.