Please stay on the official trails, and do not walk where others have started a new trail.
The most consistent poppy-bearing land in California is here in the western end of the Antelope Valley. This park land is not cultivated to artificially produce wildflower blooms, rather it is left to the forces of nature, which vary each year.
Poppies may begin to bloom as early as February, and last into June, or rarely July if rains continue through the spring. Seeds may stay dormant for years until they are germinated by just the right conditions.
The timing of rain, not the amount, is the primary condition that affects bloom duration and intensity. Moderate rains, beginning in fall and continuing regularly throughout the winter, are what triggers spectacular desert wildflowers. However, significant late-season rain storms after an otherwise dry fall and winter have surprised us with a "March Miracle!"
Other factors can unexpectedly alter bloom predictions. Late-winter freezes can nip germination in the bud if rains didn't come early enough for roots to grow deep, where they're protected by the soil. Also, early heat waves can wipe out a bloom in three days if soil moisture is shallow after years of drought, leaving desiccated buds clinging to dry stems.
Typically, the peak bloom is late March-early April. The peak has shifted forward two weeks from a generation ago when the peak was mid-April, likely due to climate change.
The California poppy's native range is from Baja California to southern Washington, and into Nevada. The bloom season comes earlier to the south, and later to the north.