diff --git a/Scripts/check-moon-phase.ps1 b/Scripts/check-moon-phase.ps1
index a34f9af4..a530a6ae 100644
--- a/Scripts/check-moon-phase.ps1
+++ b/Scripts/check-moon-phase.ps1
@@ -1,8 +1,8 @@
 <#
 .SYNOPSIS
-	Checks the moon phase
+	Checks the Moon phase
 .DESCRIPTION
-	This script determines the moon phase and answers by text-to-speech (TTS).
+	This script determines the Moon phase and answers by text-to-speech (TTS).
 .EXAMPLE
 	PS> ./check-moon-phase
 .NOTES
@@ -12,23 +12,29 @@
 #>
 
 try {
-	$Day = (Invoke-WebRequest http://wttr.in/?format="%M" -UserAgent "curl" -useBasicParsing).Content
-	if ($Day -eq "0") {	  $Reply = "Today is "
-	} elseif ($Day -eq "1") { $Reply = "Yesterday was "
-	} else {                  $Reply = "$Day days ago "
+	$LunarCycle = 29.53058770576 # in days
+	$LunarHalfCycle = $LunarCycle / 2.0
+	$Phases = @("New moon", "Waxing crescent moon", "First quarter moon", "Waxing gibbous moon", "Full moon", "Waning gibbous moon", "Last quarter moon", "Waning crescent moon")
+	$PhaseLength = $LunarCycle / 8.0
+	$PhaseHalfLength = $PhaseLength / 2.0
+
+	$RefDate = get-date -Year 2021 -Month 12 -Day 4 -Hour 6 -Minute 43 # Dec 4, 2021 06:43 UTC [New Moon]
+	$Now = get-date
+	$TimeInterval = New-TimeSpan -Start $RefDate -End $Now
+	$Days = $TimeInterval.TotalDays
+
+	$MDays = $Days % $LunarCycle
+	$PhaseIndex = [int]($MDays * (8.0 / $LunarCycle))
+
+	$Visibility = [math]::Round((($Days % $LunarHalfCycle) * 100) / $LunarHalfCycle)
+	$Reply = "$($Phases[$PhaseIndex]) with $($Visibility)% visibility"
+
+	$MoonAge = [math]::Round($Days % $LunarCycle)	
+	if ($MoonAge -eq "0") {	      $Reply += " today"
+	} elseif ($MoonAge -eq "1") { $Reply += " since yesterday"
+	} else {                      $Reply += ", last new moon was $MoonAge days ago"
 	}
 
-	$Phase = (Invoke-WebRequest http://wttr.in/?format="%m" -UserAgent "curl" -useBasicParsing).Content	
-	if ($Phase -eq "🌑") {       $Reply += "new moon"
-	} elseif ($Phase -eq "🌒") { $Reply += "waxing crescent moon"
-	} elseif ($Phase -eq "🌓") { $Reply += "first quarter moon"
-	} elseif ($Phase -eq "🌔") { $Reply += "waxing gibbous moon"
-	} elseif ($Phase -eq "🌕") { $Reply += "full moon"
-	} elseif ($Phase -eq "🌖") { $Reply += "waning gibbous moon"
-	} elseif ($Phase -eq "🌗") { $Reply += "last quarter moon"
-	} elseif ($Phase -eq "🌘") { $Reply += "waning crescent moon"
-	}
-	$Reply += "."
 	"✔️ $Reply"
 	& "$PSScriptRoot/speak-english.ps1" "$Reply"
 	exit 0 # success