1999
I think it was 2009 since there were 5 Saturdays in that month October.
October 2010 contains 5 weekends.
because of leap years, October has 5 weekends alternating between every 6 years and every 11 years. The next Octobers with 5 weekends will be 2021 and 2027.
2010
To determine when there were 5 weekends in a month, we look for months with 31 days where the 1st falls on a Saturday, Sunday, or Monday. The last occurrence of this was in January 2023, which had 5 weekends (January 7-8, 14-15, 21-22, 28-29) and began on a Sunday.
If you mean five Fridays and Saturdays, the last two years that happened were 2010 and 2004.
The last time there were five Fridays, Saturdays, and Sundays in October was in 2010.
2006.
3 months had five Sat-Sun weekends in 2011: January, July, and October.
October 2010
There are 14 calendar variations (7 days of the week plus leap years). Some years October will have 5 Fridays, 5 Saturdays, and 5 Sundays. October 1999, 2010, 2021, and 2032 all have 5 Fridays, 5 Saturdays, and 5 Sundays. This looks like an 11 year gap, but October 1988 and 2043 do not have 5 weekends.
2014
Using MS Works calendar - the last time it happened was in 2004. The next time will be in 2021 !