Hi Laura,
Thank you for contacting Syncfusion Support.
We have prepared the sample to display the month and day names in Spanish, which can be download from the below link.
Kindly refer the below culture script file used in the above sample.
<Code>
@Scripts.Render("~/Scripts/ej/ej.culture.es-ES.min.js")
</Code>
Regards,
Nevitha.