Rain is needed in small doses throughout the winter. Too little rain provides a poor climate for seed germination. Too much rain, and the seeds could rot or be washed away. Showers too early or too late in the season may not help the flowers bloom. Temperature is also critical.
Warm days are a good indicator of a full bloom ahead.
Cool nights can assist flower seedlings by slowing the growth of competitors like grasses and mustards. However, very cold temperatures mean bad news for blossoms. None of us knows for sure. Each year's bloom is unique in its variety, profusion and timing. From late February through March, you can find blossoms on the desert floors.