The last three time were in 1991, 1996 and 2002. The next time will be in 2013.
April 6th falls on a Saturday this year - 2013.
In 1977, when it was on a Thursday. In the other two years, the 21st of April was on a Saturday.
April 20, last fell on a Saturday in 2002 and will again fall on a Saturday in 2013.
April 11th will fall on a Saturday in 2026 and 2037. It will fall on a Monday in 2022 and 2033. The specific years where April 11th lands on either of these days can be determined by looking at the calendar patterns for leap years and the day of the week shifts.
April 20, last fell on a Saturday in 2002 and will again fall on a Saturday in 2013.
18th April 1950 was a Tuesday.
February 18th 1967 was a Saturday.
The calendar repeats every 11 years. Therefore - the next time April 20th will fall on a Saturday is 2024.
Saturday
Since the start of the 20th century, the 18th of August was on a Saturday in 1906, 1917, 1923, 1928, 1934, 1945, 1951, 1956, 1962, 1973, 1979, 1984, 1990, 2001, 2007 and 2012. It will next be on a Saturday in 2017.
Easter falls on April 18th three times during the 21st century: 2049, 2055 and 2060.
April 14, 2012 will fall on a Saturday.