That juicy, tree-ripened peach you bite into on a warm summer day is shaped during the winter months, long before the harvest. While cold weather may make it feel like the orchard is at rest, it’s actually doing some of its most important work. This behind-the-scenes process centers on chill hours, a key factor in determining the health, timing, and productivity of our fruit each year. As weather patterns become less predictable, understanding chill hours has never been more important for farmers and fruit lovers alike.
What Are Chill Hours?
Chill hours refer to the cumulative number of hours when temperatures fall between 32°F and 45°F during the winter months. For stone fruit trees—like peaches, nectarines, apricots, plums, pluots, and cherries—these hours are essential. During the fall, shorter days and cooler temperatures stimulate tree hormones that inhibit growth, keeping the trees dormant through the winter.
Dormancy isn’t inactivity, it's a natural resting phase that allows them to reset after a long growing season and prepare for what’s ahead. During this time, trees conserve energy, repair internal systems, and build the reserves they’ll need to produce strong blossoms and healthy fruit in the spring. Chill hours in the winter eventually break down the trees’ growth-inhibiting hormones. As the days grow longer and temperatures rise, the tree starts to grow again, producing the buds and blooms that will become the fruit we love.
So far, winter has been doing its job! As of February 8, 2026, Brentwood has accumulated 798 chill hours, putting us in a very encouraging position for this year’s harvest. In fact, this is some of the strongest chill accumulation we’ve seen at this point in the past five years. While chill hours are just one piece of a much larger puzzle, this steady winter cold has helped set the stage for a promising spring and summer.
The Hurdles Still Ahead
Of course, winter chill is only the beginning of the story. We still have spring bloom, weather patterns, and rainfall to move through before we know what this season will ultimately bring. From a chill-hours perspective, things are shaping up well for our fruit set—but nature always has the final say.
A few warm days last week gave the trees an early nudge, jump-starting the transition out of dormancy. This is a normal response: warm weather following sufficient cold signals to trees that it’s time to move forward. Because this warmth arrived a bit earlier than usual, it could mean an earlier bloom and fruit set this year.
An early bloom can be a good thing, but it also comes with added vulnerability. Blossoms are delicate, and once trees are in bloom, they’re more susceptible to weather extremes. Heavy rain can physically damage flowers, warm rain can increase the risk of fungal disease, and sudden cold snaps can cause injury. The earlier the bloom, the longer the window in which those challenges could arise.
Looking Ahead with Optimism
That said, history gives us reason to feel hopeful! In past seasons, we’ve often seen a strong fruit set when bloom arrives early and conditions cooperate. With solid chill hours already in place and careful orchard management guiding every step forward, we’re feeling optimistic as we head into spring.
Farming is always a balance of science, experience, and trust in the natural systems we steward. Chill hours remind us that even in the quietest months, the orchard is hard at work, laying the foundation for the fruit we’ll all enjoy in the months to come. 🍑