Happy First Frost Day!

Thanks to El Niño replacing his sister La Niña , we have enjoyed a delayed frost this fall, well beyond the average first frost day of September 14 for Calgary. We almost surpassed the extents of the Freezing Date Adjustment Factor Chart, with less than 10% probability of a frost this late!

Of interest to note is that the Average First Frost Day does not necessarily correspond with the Average End of Growing Season for perennial crops such as pastures and forages (see previous link for blow-up of map below). This map is based on an average daily temperature of less than 5°C after July 1.

This late frost is a good balance to our late Last Frost Day earlier this year, a welcome relief for many plant growers. I've heard some gardeners have even managed to grow corn this year, which can be hit and miss, depending on the location and variety of corn. Now to see how long the frost resistant kale and swiss chard hold out for!