Pack or skip
Packable down jacket for San Jose in December
Verdict
Pack it
Lows around 41°F — the packable puffer covers 90% of layering needs.
Why
San Jose in December averages highs of 57°F, lows of 41°F, 8 rainy days.
That climate means a packable down jacket earns its space in the bag. Lows around 41°F — the packable puffer covers 90% of layering needs.