In December, the weather along the John Muir Trail is quite variable, characterized by cold temperatures and frequent precipitation events. Temperatures often range from highs around 8°C to lows reaching -24°C, with instances of both light and heavy snowfalls. There are periods of sunshine, but cloud cover and overcast skies are common, contributing to the cold and sometimes harsh conditions. Intermittent snowfall, freezing rain, and cloudy days underscore the wintery setting, with snowfall playing a significant role, especially in higher elevations. The trail in December presents a challenging environment, as the combination of cold, precipitation, and varied weather patterns highlight the demanding winter terrain.
The Sierra Nevada region of the John Muir Trail experiences varied weather conditions throughout December. At Happy Isles, temperatures fluctuate widely. Early in the month sees sunny spells with highs reaching up to 12°C, while nighttime temperatures drop to -10°C. Mid-month, heavy snow showers blanket the area with up to 51 mm of snowfall, ushering highs down to -5°C.
Further along at Sunrise Creek, the weather remains harsh, with light freezing rain and heavy snow showers leading to significant precipitation totals. Highs settle around 3°C, contrasting starkly with lows that can plummet to -15°C during clear, sunny nights.
Lower Cathedral Lake experiences periods of sunshine, briefly interrupted by moderate snow showers and heavy rain. With highs peaking at 7°C and lows bottoming out at -14°C, the region oscillates between sunny and snowy conditions.
Tuolumne Meadow weather mirrors Lower Cathedral Lake, with frequent sunny days and moderate snow showers. While daytime highs manage around 9°C, freezing nights persist, with lows diving as low as -20°C on overcast days.
Donahue Pass displays a mix of light freezing rain and snow showers, peaking at a modest 9°C but dropping to a frosty -24°C. Snow showers deliver up to 17 mm of precipitation, reinforcing the wintry backdrop.
Garnet Lake is part cloud, part sun throughout the month, occasionally bedecked by moderate snowfalls. Here, temperatures swing from 9°C in sunny periods to -20°C during chilly nights. Partly cloudy skies often herald brief snowfalls or freezing rain.
In contrast, Red's Meadow succumbs to frequent heavy snow showers, especially early on when temperatures hit -10°C. Periods of sunshine make an appearance, but not without dense clouds and overcast spells keeping the environment cold, with lows dropping to -22°C.
Lake Virginia alternates between partly cloudy and sunny, interspersed with light freezing rain. December ends on this section with fewer snow showers, but temperatures can still dip to -20°C.
As the trail progresses to McClure Meadow, periodic heavy snow showers linger. Days typically enjoy clearer skies, up to 15°C, with nights notably cold, often around -9°C. Sunshine dominates the weather toward the latter part of the month, drawing an end to the intermittent snow.
At Whitney Portal, December is relatively more benign compared to other areas, as light precipitation occasionally dampens the trail. Still, mild sunny days can hit 16°C, yet nights consistently dip below freezing. This section wraps up the December journey with partly overcast skies, sustaining the chilly yet less tempestuous atmosphere characteristic for this part of the Sierra Nevada during this month.
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