In April, Castro Valley typically sees daytime highs of 18.9°C and overnight lows around 7.9°C. Compared to the annual average high of 20.0°C, April runs -1.1°C.
April in Castro Valley averages a daytime high of 18.9°C and an overnight low of 7.9°C.
April runs -1.1°C compared to Castro Valley's annual average high of 20.0°C, ranking #7 of 12 months by warmth.
Plan for daytime highs near 18.9°C and cooler evenings around 7.9°C.