Here are the contribution of the two major goods producing sectors (construction and manufacturing) as a percentage of total employment. These are seasonally unadjusted with 3 month moving average applied (CANSIM table 282-0111).
And the service producing sectors. There is seasonality in the education and recently in the business and building services sectors as well.
The latter half of 2011 has seen a welcome rebound to the manufacturing sector as well as a drop in construction employment as a percentage of total employment. Construction employment is still high relative to its historical limits of the past 15 years and remains a larger part of BC's workforce than previous. If construction were to stumble closer to levels seen earlier in the century, there is some hope that manufacturing can fill at least some of the gap, though at what quality remains to be seen.
What causes seasonality? With education there are typically layoffs in the summer break as teachers without full time positions are terminated then re-hired in the fall. The troughs in education employment correspond to the summer months. The recent uptick in construction employment peaked in the late spring and is now completing. I am not sure why this occurred. Other sectors show mild seasonality but nothing immediately obvious that could be of much use.
Despite BC not showing as strongly in the latest labour force survey, it nonetheless appears that parts of BC's economy are recovering alongside the rest of North America and that is a good thing.