Pack or skip
Packable down jacket for Denver in September
Verdict
Pack it
Lows around 48°F — the packable puffer covers 90% of layering needs.
Why
Denver in September averages highs of 77°F, lows of 48°F, 7 rainy days.
That climate means a packable down jacket earns its space in the bag. Lows around 48°F — the packable puffer covers 90% of layering needs.