Weather conditions now vary unpredictably with every season. The last three years – 2023, 2024 and 2025 – are in a tie for hottest years ever recorded worldwide . But so far this year California is drought-free for the first time in 25 years, according to new data from the U.S. Drought Monitor (San Francisco Chronicle, Jan.13, 2026). As of mid-January the state’s major reservoirs are at 130% of capacity and the Sierra snowpack is 89% of average. However, drought conditions could return if there’s not enough rainfall in March and April, the months during which the majority of the annual rainfall for the Central Valley has usually fallen.
The summer growing season here in the Central Valley now begins in April and can last until mid-October with daytime temperatures exceeding 100 degrees more frequently for longer periods of time and nighttime temperatures remaining above 70 degrees for weeks. The winter dormancy period is now shorter, reducing the number of hours of cold temperatures that produce the ‘chill factor’ necessary for good fruit and nut production.
With summer temperatures now regularly exceeding the previously normal highs and significant rainfall arriving on a variable schedule every year gardeners’ observations of the microclimates in every inch of our gardens become increasingly important. Determining the best and worst growing spots can help us make adjustments for existing plants and trees as well as help us choose new plants and trees that can withstand long hot summers, persistent drought conditions and atmospheric river bombs that leave behind soggy soil and thick fog on winter days. Fortunately, plant hybridizers and growers are working hard on developing and marketing plants and trees that will be better able to tolerate weather extremes.
In every garden there are micro-climates created by sun/shade patterns, wind patterns and structures that block or divert rain and wind as well as differing soil types and their differing abilities to retain water and drain well.
Most every growing thing needs afternoon shade during Central Valley summers. Planting sun-tolerant shade trees and large shrubs on the western and southern sides of a property isn’t always possible. Some of the hottest, sunniest spots in a garden may not be suitable for growing. When planting in sunnier spots with little shade try to tailor irrigation to each plant species and to the duration of daily sunlight in each spot, not just to a drought-tolerant zone.
Microclimates that are created near south- or west-facing structures that reflect and retain the day’s heat will be hotter than other locations. Structures that block the prevailing northwest breeze or storm winds that arrive from the west cause heat to increase in those locations. Large trees also block sun and wind and large tree roots take up huge amounts of water from surrounding areas, creating drier soil conditions in those areas.
Amending the soil to improve water retention and drainage can no longer be a process of tilling in a single bag of compost or humus when planting. The benefits of adding copious amounts of organic materials to native soil will become obvious in just a few years as the soil itself begins to restructure significantly.
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Written by UC Master Gardener Elinor Teague