Spring frost is something that producers need to consider into late May and in some areas of Manitoba, there is an elevated risk of occurence into the month of June.
Average Date of last Spring Frost – is considered after May 19th. In the Portage la Prairie, Langruth, Pilot Mound, Morden and Altona regions there is less than a 50 percent chance that frost will occur after the 19th. In other areas, the last spring frost occurs, on average, after May 24. On higher elevations, central Interlake and the south-eastern regions of Manitoba can expect frost during the first week of June in one out of every two years. Figure 1: Manitoba Average Last Spring Frost
1 in 4 year risk– that the last frost will occur about eight days later than average. This means a 25 % risk that the last spring frost will occur after May 24 in the Portage la Prairie and Altona regions. In most other regions of Manitoba, a 25% risk of a spring frost in the first week of June and in the Riding Mountain and Hodgson regions, that is will occur later than mid-June. Figure 2: Manitoba Last Spring Frost (1 in 4 years)
1 in 10 year risk – a 10% risk that the last spring frost will occur later than June 3 for most regions. A recent example of this is in 2009, when there was a wide spread frost through the agricultural growing region on June 6th. Figure 3: Manitoba Last Spring Frost (1 in 10 years)
If a frost does occur, please refer to MAFRI`s Spring Frost Damage Bulletin to help assess the situation at http://www.gov.mb.ca/agriculture/crops/cropproduction/faa23s00.html