Contra Costa County, California Weather by Month

By | January 11, 2024

Contra Costa County, located in the San Francisco Bay Area of California, experiences a Mediterranean climate characterized by mild, wet winters and warm, dry summers. The region is known for its diverse landscapes, including urban areas, agricultural zones, and scenic hills. Here’s a detailed breakdown of the weather by month in Contra Costa County:

January-February: Winter Months

  • January and February are the coldest months in Contra Costa County, with daytime temperatures typically ranging from 50 to 60 degrees Fahrenheit (10 to 16 degrees Celsius).
  • Nights can be cool, with temperatures often dropping into the 30s. The region experiences its highest rainfall during these months, contributing to lush greenery and replenishing water supplies.┬áSee for climate and weather in San Jose, California.
  • Occasionally, the area may witness some fog, especially in the mornings.

March-April: Transition to Spring

  • March marks the beginning of the transition to spring. Daytime temperatures start to warm up, ranging from 60 to 70 degrees Fahrenheit (16 to 21 degrees Celsius).
  • As spring progresses into April, temperatures continue to rise, and the landscape becomes more colorful with blooming wildflowers. Rainfall decreases, but sporadic showers are still possible.

May-June: Late Spring

  • May and June bring a significant increase in temperatures. Daytime highs can range from 70 to 80 degrees Fahrenheit (21 to 27 degrees Celsius).
  • Late spring is characterized by mild and pleasant weather, making it an ideal time for outdoor activities. Rainfall is minimal during this period, and the region starts to experience the dry season.

July-August: Summer Months

  • July and August are the warmest months in Contra Costa County. Daytime temperatures often exceed 90 degrees Fahrenheit (32 degrees Celsius).
  • Nights remain relatively warm, with temperatures staying in the 60s. Humidity is low during the summer months, contributing to the dry heat.
  • This period is marked by clear skies and abundant sunshine, making it a popular time for outdoor events, festivals, and recreational activities.

September-October: Early Fall

  • September marks the beginning of the transition to fall, but temperatures remain warm, ranging from 80 to 90 degrees Fahrenheit (27 to 32 degrees Celsius).
  • Fall foliage begins to appear in October, and daytime temperatures gradually decrease. This period still experiences dry conditions, with minimal rainfall.
  • The warm weather makes early fall a pleasant time for outdoor activities, and residents may start to see the first signs of the upcoming rainy season.

November-December: Fall into Winter

  • November sees a further decline in temperatures, with daytime highs ranging from 60 to 70 degrees Fahrenheit (16 to 21 degrees Celsius).
  • December marks the beginning of winter, but daytime temperatures are still relatively mild compared to many other parts of the country, ranging from 50 to 60 degrees Fahrenheit (10 to 16 degrees Celsius).
  • Nights can be cool, with temperatures occasionally dropping into the 30s. Winter is the rainy season for this region, and occasional storms bring much-needed precipitation.

Throughout the year, Contra Costa County experiences the characteristic climate of the Mediterranean region, with distinct seasons. Residents and visitors can enjoy a variety of outdoor activities, from hiking and cycling in the scenic hills to exploring urban areas and enjoying the agricultural landscapes. It’s advisable to stay informed about local weather forecasts, especially during the winter months when rain can be more frequent, to be prepared for any changes in conditions.

Contra Costa County, California