DPPt dates

All these dates decrease the encounter rate by 3% in grass and 1% in caves:
January 1st
March 21st (Spring Equinox)
August 6th (Hiroshima)
August 9th (Nagasaki)
September 11th (911) ** Only in JPN DP
September 23rd (Autumn Equinox)

All these dates decrease the encounter rate by 1.5% in grass and 0.5% in caves:
August 13th (Obon, lantern festival)
August 14th (Obon)
August 16th (Obon)
November 3rd (Culture Day)
December 25th (Christmas)
December 31th (New Year's Eve)

All these dates increase the encounter rate by 3% in grass and 1% in caves:
January 12th (Masuda's Birthday)
July 7th (Tanabata)

All these dates increase the encounter rate by 1.5% in grass and 0.5% in caves:
January 11th (Opening the Mirror)
February 3rd (Setsubun)
February 11th (National Foundation Day)
February 12th (Lincoln's Birthday)
March 3rd (Hinamatsuri)
March 17th (St Patrick's Day)
March 25th (Viernes Santo)
April 1st (School Entrance Ceremony)
April 25th (Italian Liberation Day)
April 29th (Greenery Day)
May 3rd (Constitution Memorial Day)
May 5th (Children's Day)
May 8th (End of WWII, France)
May 29th (Whit Monday)
June 2nd (Festa della Repubblica)
June 21st (dummy)
July 4th (Independence Day)
July 14th (Fête Nationale)
July 24th (dummy)
August 15th (Obon, Assumption)
August 28th (Bank holiday)
September 15th (Mid-Autumn Festival)
September 20th (?)
October 3rd (Tag der Deutschen Einheit)
October 12th (Fiesta Nacional de España)
October 30th (?)
November 1st (All Saints' Day)
November 11th (Veteran's Day, WWI Armistice Memorial Day)
November 16th (Volkstrauertag)
December 6th (Día de la Constitución)
December 8th (Virgin Immaculate Conception Day)
December 23rd (Emperor Akihito's Birthday)
December 24th (Christmas Eve)