Frost dates are set by finding an average based on the last 20 years. The last frost date for the Vancouver, BC area is March 28. This is the last date, on average, when we might experience frost at night. The first average frost date of autumn falls on November 2 in Vancouver. These dates will be different if you live outside of the Vancouver area.
To find your first and last frost dates, search Google for the phrase “average frost date” plus the name of your town or a town nearby. Remember that these dates are averages only, and can fluctuate dramatically from year to year.
Frost dates give growers a good idea of how early or late it might be practical to sow seeds, depending on the variety, its germination time, and its days to maturity.