idea Arcade Date function Month range = 0-11??? in Developers Ideas

Arcade Date function Month range = 0-11???

ThomasHoman — Mon, 11 May 2026 16:33:25 GMT

Hello,

Is it possible to bring the Arcade Date function into full reality?

In working with the Arcade Date function in Calculate Field the valid month range of 0-11 seems absolutely off especially when the rest of the past variables are based on reality. Year and Day components of the date are the normal values but the month is a 0 based number ...

Time values obviously can have a valid 0 value but month doesn't seem like a good candidate for this.

Am I missing something?

Thanks for the consideration

Tom

Re: Arcade Date function Month range = 0-11???

ChrisUnderwood — Wed, 27 May 2026 15:50:33 GMT

Hello @ThomasHoman , my apologies if this is rather unhelpful, but no, you are not missing something.

https://developers.arcgis.com/arcade/function-reference/date_functions/#date1

"month: Number - The month (0-11) where 0 is January and 11 is December."

Re: Arcade Date function Month range = 0-11???

ThomasHoman — Mon, 08 Jun 2026 16:35:11 GMT

@ChrisUnderwood Obviously any edits to this would break a bunch of existing code but is there a way to correct (idea submittal) or can you share specific reasons for this odd case?

Re: Arcade Date function Month range = 0-11???

ChrisUnderwood — Thu, 11 Jun 2026 15:28:20 GMT

@ThomasHoman If this Idea gains enough Kudos then it should get considered, but as you say, changing it would break lots of things. I presume there is some historical reason for using 0-11, but I don't know any details.

Meanwhile, the ISOMonth function does appear to offer a 1-12 Index instead,
https://developers.arcgis.com/arcade/function-reference/date_functions/#isomonth

And there are some other methods described in this Knowledge Article.
https://support.esri.com/en-us/knowledge-base/how-to-extract-names-of-the-month-from-a-date-field-usi-000033574

Re: Arcade Date function Month range = 0-11???

ThomasHoman — Fri, 12 Jun 2026 14:55:03 GMT

Thanks much sir for the additional references.