Web Map shows wrong "beach sampling date" in popup window

Question

I created a web map of beach monitoring sites and results for San Mateo County Calif.  The popup includes the sampling date.  The date in the popup does not match the date in the underlying data (feature service or shapefile or Excel table).  For example:

Data says 7/5/2011,   web map popup shows  7/4/2011 5:00 PM
Data says 5/17/2011, web map popup shows 5/16/2011 5:00 PM

This is consistently wrong for all the map points in all the popups.

The operational layers are on an ArcGIS server behind our county firewall, so you can't see them.  So I've documented and illustrated the problem in the attached 2-page PDF.  I hope you'll take a look and help figure this out.

Thanks.

Date display issue in AGO web map.pdf

IMG_20201103_093258.jpg

cartograham · Answer

The responses here identify the problem, but the resolution is actually present in the ArcGIS/ArcMap documentation here:

Calculate Field examples—Help | ArcGIS for Desktop

A slight tweak the examples gives the resolution, using the Field Calculator:

arcpy.time.ParseDateTimeString(!field1!) + datetime.timedelta(hours=12)

RichardCitkowicz · Answer

I am uploading a feature class from ArcMap 10.1 without a date edit and date created field and turning this on after the feature service is published.

DonBarker · Answer

Great, Mike.  This makes sense.

Thanks for taking time to reply with explanation and suggestions.