Determining how much damage will be done to fruit trees as a result of the cold depends on bloom stage, length of the cold period, how low the temperature was and type of fruit.
During dormancy, fruit tree buds are hardy to winter temperatures. As the buds develop and swell, they lose their hardiness and become more susceptible to cold injury.
Washington State University published a chart that shows the effect of cold temperatures on fruit trees during varying stages of flowering. You can reference that chart here: https://cpg.treefruit.wsu.edu/
Here is an example to help you understand how to read the chart. For apricot trees in their first bloom period, 10% of the buds would be damaged/killed after 30 minutes at 24 degrees F. 90% of the buds would be damaged/killed at 14 degrees F for 30 minutes at that same flowering stage.
