You are not imagining it, October was a cold month.
The University of Waterloo weather station said it was the coldest October we have seen in the last ten years.
But, the whole month wasn't that frigid.
The weather station found the first eleven days of the month were, on average ten degrees higher than the rest of October.
And yes, we did see some signs of winter over the past 31 days, October 14th marked the first frost of the season.
Precipitation wise, the beginning and end of the month were especially wet with a total of 94.2 mm of rain falling over 31 days.
From The University of Waterloo Weather Station:
Summary for October 2018:
-Maximum Temperature 28.5°C
-Minimum Temperature -2.6°C
-Average Daily High Temperature 12.7°C (Long term average 13.5°C)
-Average Daily Low Temperature 3.7°C (Long term average 2.9°C)
-Total Precipitation 94.2 mm (Long term average 67.4 mm)