Union City Weather Forecast

    • 58
    • 71

    Mostly Cloudy

    • 58
    • 73

    Partly Sunny

    • 58
    • 75

    Partly Sunny

    • 60
    • 84

    Partly Sunny

    • 61
    • 86

    Partly Sunny

    • 59
    • 80

    Partly Sunny

Today 20 Sep San Francisco Bay Shoreline

Mostly cloudy. Highs in the upper 60s to mid 70s. West Winds 5 to 15 Mph.

Tonight 20 Sep San Francisco Bay Shoreline

Mostly cloudy. Lows in the upper 50s. West Winds 5 to 15 Mph.

Graph Plots Open in Graphs

  • Temperature Forecast NOAA

  • Temperature Real-Time

Union City Temperature Statistics

September Temperature

Hayward, Hayward Air Terminal (6.2 miles)

  • Lowest 7 September, 2026

    55.7 °F

  • Average September

    68.2 °F

  • Highest 9 September, 2026

    99.6 °F

Climate (2021–2026)

Hayward, Hayward Air Terminal (6.2 miles)

Take a look at our website widgetsAvailable free! Find Out More

  • Average Low 2021–2026

    52.4 °F

  • Average 2021–2026

    59.8 °F

  • Average High 2021–2026

    69.2 °F
Get WillyWeather+ to remove ads