In July 2027 the son-eomneun days fall on 3, 12, 13, 22, 23. 5 in all. These are days whose lunar date ends in 9 or 0 — long the first thing people check before moving house or opening a shop.
July 17: 제헌절; July 19: 대체공휴일(제헌절). Taken from Korea Astronomy and Space Science Institute open data.
July 7: 소서; July 23: 대서. Computed from the sun's ecliptic longitude, not looked up in a table.
These dates hold for every visitor. A son-eomneun day is fixed by the lunar calendar alone and has nothing to do with your birth chart. What a given day means for you needs a birth date — there is no auspicious day that holds for everybody.