diff --git a/repository/ZTimestamp-Core/ZTimestampFormat.class.st b/repository/ZTimestamp-Core/ZTimestampFormat.class.st
index fec307a..553f27b 100644
--- a/repository/ZTimestamp-Core/ZTimestampFormat.class.st
+++ b/repository/ZTimestamp-Core/ZTimestampFormat.class.st
@@ -361,7 +361,13 @@ ZTimestampFormat >> compileSpecification [
 	| elements |
 	elements := self specificationElements.
 	formatter := elements
-			collect: [ :each | each isCharacter ifTrue: [ each ] ifFalse: [ (#format: , each , #On:) asSymbol ] ].
+			collect: [ :each | 
+				each isCharacter 
+					ifTrue: [ each ] 
+					ifFalse: [
+						(each beginsWith: #timeZone)
+							ifTrue: [ (#format: , each , #'On:usingOffset:') asSymbol ]
+							ifFalse: [ (#format: , each , #On:) asSymbol ] ] ].
 	parser := elements
 			collect: [ :each | 
 				each isCharacter
@@ -627,12 +633,16 @@ ZTimestampFormat >> format: object nanosecondOn: stream [
 ZTimestampFormat >> format: object on: stream [
 	"Format object on stream according to my specification"
 
-	| local |
+	| local offset|
 	local := self gmtToLocal: object.
+	offset := self actualOffsetForTimestamp: object.
 	formatter do: [ :each |
 		each isCharacter 
 			ifTrue: [ stream nextPut: each ] 
-			ifFalse: [ self perform: each with: local with: stream ] ]
+			ifFalse: [ 
+				each numArgs = 2
+					ifTrue: [ self perform: each with: local with: stream ]
+					ifFalse: [self perform: each with: local with: stream with: offset ] ] ]
 ]
 
 { #category : #formatters }
@@ -654,6 +664,13 @@ ZTimestampFormat >> format: object timeZoneAbbreviatedLongOn: stream [
 		ifFalse: [ stream << (self abbreviationForTimeZoneOffset: offset) ]
 ]
 
+{ #category : #formatters }
+ZTimestampFormat >> format: object timeZoneAbbreviatedLongOn: stream usingOffset: offset [
+	offset isZero
+		ifTrue: [ stream << #UTC ]
+		ifFalse: [ stream << (self abbreviationForTimeZoneOffset: offset) ]
+]
+
 { #category : #formatters }
 ZTimestampFormat >> format: object timeZoneAbbreviatedOn: stream [
 	| offset |
@@ -663,6 +680,13 @@ ZTimestampFormat >> format: object timeZoneAbbreviatedOn: stream [
 		ifFalse: [ stream << (self abbreviationForTimeZoneOffset: offset) ]
 ]
 
+{ #category : #formatters }
+ZTimestampFormat >> format: object timeZoneAbbreviatedOn: stream usingOffset: offset [
+	offset isZero
+		ifTrue: [ stream << #UTC ]
+		ifFalse: [ stream << (self abbreviationForTimeZoneOffset: offset) ]
+]
+
 { #category : #formatters }
 ZTimestampFormat >> format: object timeZoneOn: stream [
 	| offset |
@@ -675,6 +699,16 @@ ZTimestampFormat >> format: object timeZoneOn: stream [
 		printOn: stream base: 10 length: 2 padded: true 
 ]
 
+{ #category : #formatters }
+ZTimestampFormat >> format: object timeZoneOn: stream usingOffset: offset [
+	stream nextPut: (offset positive ifTrue: [ $+ ] ifFalse: [ $- ]).
+	offset hours abs
+		printOn: stream base: 10 length: 2 padded: true.
+	stream nextPut: $:.
+	offset minutes
+		printOn: stream base: 10 length: 2 padded: true 
+]
+
 { #category : #formatters }
 ZTimestampFormat >> format: object timeZoneZOn: stream [
 	| offset |
@@ -690,6 +724,19 @@ ZTimestampFormat >> format: object timeZoneZOn: stream [
 				printOn: stream base: 10 length: 2 padded: true ]
 ]
 
+{ #category : #formatters }
+ZTimestampFormat >> format: object timeZoneZOn: stream usingOffset: offset [
+	offset isZero
+		ifTrue: [ stream nextPut: $Z ]
+		ifFalse: [ 
+			stream nextPut: (offset positive ifTrue: [ $+ ] ifFalse: [ $- ]).
+			offset hours abs
+				printOn: stream base: 10 length: 2 padded: true.
+			stream nextPut: $:.
+			offset minutes
+				printOn: stream base: 10 length: 2 padded: true ]
+]
+
 { #category : #formatters }
 ZTimestampFormat >> format: object weekdayNameAbbreviatedCapitalizedOn: stream [
 	stream << ((self weekdayNames at: object dayOfWeek) copyFrom: 1 to: 3)
diff --git a/repository/ZTimestamp-GT/ZTimezone.extension.st b/repository/ZTimestamp-GT/ZTimezone.extension.st
index d4f26dc..dca700e 100644
--- a/repository/ZTimestamp-GT/ZTimezone.extension.st
+++ b/repository/ZTimestamp-GT/ZTimezone.extension.st
@@ -141,9 +141,13 @@ ZTimezone >> gtViewTransitionsIn: composite [
 	^ composite columnedList
 		title: 'Transitions';
 		items: [ self resolvedTransitions ];
-		column: 'Start absolute' text: [ :association | association key ];
-		column: ('Start ' , self id) 
-			text: [ :association | ZTimestampFormat isoTZ timezone: self; format: association key ];
+		column: 'Start absolute' 
+			text: [ :association | association key ];
+		column: 'Start local' 
+			text: [ :association | 
+				((ZTimestampFormat fromString: '2001-02-03 T 16:05:06+00:00') timezone: self; format: association key - 1 second) , 
+				' > ' , 
+				((ZTimestampFormat fromString: '16:05:06+00:00') timezone: self; format: association key) ];
 		column: ('Start ' , ZCurrentTimezone value id) 
 			text: [ :association | ZTimestampFormat isoTZ useCurrentTimezone; format: association key ];
 		column: 'Subzone' text: [ :association | association value description ]
diff --git a/repository/ZTimestamp-Tests/ZTimestampFormatTests.class.st b/repository/ZTimestamp-Tests/ZTimestampFormatTests.class.st
index 30839a0..c6b849a 100644
--- a/repository/ZTimestamp-Tests/ZTimestampFormatTests.class.st
+++ b/repository/ZTimestamp-Tests/ZTimestampFormatTests.class.st
@@ -287,6 +287,30 @@ ZTimestampFormatTests >> testTimeParsing [
 		equals: (ZTimestamp year: 1 month: 1 day: 1 hour: 23 minute: 30 second: 19).
 ]
 
+{ #category : #accessing }
+ZTimestampFormatTests >> testTransitionFormatting [
+	| t1 t2 |
+	t1 := ZTimestamp fromUnixTime: 1679792400. "winter->summer"
+	t2 := ZTimestamp fromUnixTime: 1698541200. "summer->winter"
+	ZCurrentTimezone
+		value: ZTimezone europeBrussels
+		during: [
+			self
+				assert: (ZTimestampFormat isoTZ useCurrentTimezone; format: t1)
+				equals: '2023-03-26T03:00:00+02:00'.
+			self
+				assert: (ZTimestampFormat isoTZ useCurrentTimezone; format: t1 - 1 second)
+				equals: '2023-03-26T01:59:59+01:00'.
+
+			self
+				assert: (ZTimestampFormat isoTZ useCurrentTimezone; format: t2)
+				equals: '2023-10-29T02:00:00+01:00'.
+			self
+				assert: (ZTimestampFormat isoTZ useCurrentTimezone; format: t2 - 1 second)
+				equals: '2023-10-29T02:59:59+02:00'.
+ ]
+]
+
 { #category : #testing }
 ZTimestampFormatTests >> testWeekdayNames [
 	| timestamp |