The day for today is taken from the first 3 hour forecast. If it is after 9:00pm it will return tomorrows day instead of today. strDate() should be used instead. In the section "Get 3 hourly index at start of next day" replace this:
String today = forecast->dt_txt[0].substring(8, 10);
with this:
String today = strDate(now()).substring(4, 6);
The day for today is taken from the first 3 hour forecast. If it is after 9:00pm it will return tomorrows day instead of today. strDate() should be used instead. In the section "Get 3 hourly index at start of next day" replace this:
String today = forecast->dt_txt[0].substring(8, 10);
with this:
String today = strDate(now()).substring(4, 6);