Grinnell Lake Weather Forecast

    • 32
    • 50

    Mostly Sunny

    • 37
    • 59

    Sunny

    • 39
    • 61

    Mostly Sunny

    • 39
    • 60

    Mostly Sunny

    • 37
    • 59

    Mostly Sunny

    • 36
    • 57

    Mostly Sunny

Today 29 Sep Upper San Joaquin River

Warmer, sunny. Patchy smoke late in the afternoon. Highs 53 to 71. Northeast Winds 5 to 15 Mph. Gusts up to 45 Mph decreasing to 30 Mph in the afternoon.

Tonight 29 Sep Upper San Joaquin River

Clear. Lows 37 to 49. Northeast Winds 5 to 15 Mph with Gusts to around 45 Mph.

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  • Temperature Forecast NOAA

  • Temperature Real-Time

Grinnell Lake Temperature Statistics

September Temperature

Mammoth Yosemite Airport (10.6 miles)

  • Lowest 18 September, 2026

    28.4 °F

  • Average September

    58 °F

  • Highest 9 September, 2026

    84.2 °F

Climate (2021–2026)

Mammoth Yosemite Airport (10.6 miles)

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  • Average Low 2021–2026

    29.4 °F

  • Average 2021–2026

    45.7 °F

  • Average High 2021–2026

    60.5 °F
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