Need Help with Item Value and dynamic Item Label

Setup, Configuration and Use Scripts & Rules
1

Hi i am using OH2 on Win10.
I Wold like to have an Item with Value Max. Temperature of the day and as Label the Date and Time of this Value.

This is my Code:

Item

Number 	 Aquara_Temp_Wz_Max "Wz.MAX.Temp [%.1f °C]"

Sitemap

Text item=Aquara_Temp_Wz_Max   icon="temperature"

Rule

rule "Test"

when
	Time cron "0/2 * * ? * * *"
	then
	
    val maxWz = Aquara_Temp_Wz.maximumSince(now.withTimeAtStartOfDay).state as DecimalType

	Aquara_Temp_Wz_Max.label= Aquara_Temp_Wz.maximumSince(now.withTimeAtStartOfDay).timestamp.toString
	Aquara_Temp_Wz.maximumSince(now.withTimeAtStartOfDay).state as DecimalType

end

The Rule is working and my Item gets the Max.Temp. Value and The Label with the Timestamp ->
Mon Mar 04 10:08:09 CET 2019.
How cam i format this Timestamp in different way?
Thanks for any advice