Orchard Frost - Critical Temperatures for Various Fruits

The temperature at which fruit buds are injured depends primarily on their stage of development.
Orchard Frost - Critical Temperatures for Various Fruits - Articles


Examples of stages of fruit bud development: top left - apple tight cluster; top right - apple first bloom; lower left - sweet cherry first white; lower right - peach pink.

As flowers begin to swell and expand into blossoms, they become less resistant to freeze injury. Not all blossoms on a tree are equally tender. Resistance to freeze injury varies within trees as it does between orchards, cultivars, and crops. Buds that develop slowly tend to be more resistant. As a result, some buds are usually killed at higher temperatures, while others are resistant at much lower temperatures.

The table below shows the average temperatures required to kill 10 percent and 90 percent of buds if they are exposed for 30 minutes. Consideration should also be given to weather conditions preceding cold nights. Prolonged cool weather tends to increase bud hardiness during the early stages of bud development.

Stage of Development10% kill (°F)90% kill (°F)
Adapted from 1989 Spray Guide for Tree Fruits in Eastern Washington. Bulletin EBO419. E. H. Beers, coordinator.
  1. For Red Delicious. Golden Delicious and Winesap are approximately 1 degree hardier. Rome Beauty is 2 degrees hardier, except after petal fall when all cultivars are equally tender.
  2. For Bartlett. D'Anjou is similar but may bloom earlier and therefore may be more tender than Bartlett at the same date.
Apples a
Silver tip152
Green tip1810
½-inch green2315
Tight cluster2721
First pink2824
Full pink2825
First bloom2825
Full bloom2825
Post bloom2825
First swelling181
Calyx green215
Calyx red239
First pink2515
First bloom2621
Full bloom2724
Post bloom2825
Pears b
Scales separating150
Blossom buds exposed206
Tight cluster2415
First white2519
Full white2622
First bloom2723
Full bloom2824
Post bloom2824
Sweet cherries 
First swelling175
Side green229
Green tip2514
Tight cluster2617
Open cluster2721
First white2724
First bloom2825
Full bloom2825
Post bloom2825
First swelling15-
Tip separates200
Red calyx229
First white2414
First bloom2519
Full bloom2722
In the shuck2724
Green fruit2825

For additional information, please refer to the Penn State Extension Tree Fruit Production Guide .