We are easily three, and maybe four weeks ahead of “average” bloom dates in the Winchester area. Apples flower buds are ranging from tight cluster (Fuji) to open cluster (Red Delicious) to about 10% bloom open (Pink Lady). Peaches are at full bloom to petal fall. Cherries are at first bloom.

Pink Lady–10% bloom open.

Sweet Breeze peach — full bloom

Sweetheart/G.12 sweet cherry — full bloom

The National Weather Service is forecasting a potential low of 34F on Monday night (Tuesday morning) and a potential low of 38F on Tuesday night (Wednesday morning). If you have areas that are known frost pockets (low areas with minimal or no air drainage) in your orchard, the temperatures may be closer to the freezing point.

However, these temperatures should be above the critical temperature for damage. Apples in tight cluster to first bloom should be able to withstand temperatures down to 27 or 28F until there is a 10% kill, and down to 21F for tight cluster and 24-25F for pink to full bloom until there is a 90% kill.

Peaches in full bloom to petal fall can withstand 27-28F until there is a 10% kill, and down to 24-25F until there is a 90% kill.

Cherries in first to full bloom can withstand 28F until there is a 10% kill, and down to 25F until there is a 90% kill.

Pears in first to full bloom can withstand 27-28F until there is a 10% kill, and down to 23-24F until there is a 90% kill.

Nonetheless, it’s going to be a long time until we get through the last potential frost occurrence. The NOAA cites April 23 as the day beyond which we have only a 10% chance of having a temperature below 28F. You can look up other locations, temperatures , and percent chances for a frost occurrence here: NOAA Freeze/Frost Occurrence Data.

Here are pdf links for the Washington State University fact sheets on the critical temperatures for flower buds:

• Apples
• Peaches
• Cherries
• Pear