Depending on the day hike, you may think insulation is not really an essential. But at higher altitudes, when the sun goes down, so does the temperature. And if your day trip ends up going long, you could be unexpectedly out in the cold.
The best thing to do before your day hike is to check the weather. Look at the day’s highs, lows and precipitation forecast to determine what you need to wear, and what you should pack to keep you warm in case of emergency.
If I’m hiking in the Valley, I usually just throw one of the cheap emergency blankets into the bottom of my pack because I know that in the spring and fall near the Millerton Lake or Auberry area, you’re not going to run into any extreme cold temperatures. The blanket simply reflects heat, so I can wrap that underneath one of my clothing layers to provide a bit of insulation if needed. If I’m hiking in the Sierras or anywhere else where temperatures can drop easily, there are a few things I always pack.
One of my go-to items I pack for insulation is a down vest. I stuff my down vest into a one-liter dry sack and it packs down to a convenient size that I hardly notice in my daypack. The vest keeps your core warm while giving you the freedom to move your arms without restriction, and since I usually wear a long sleeve sun shirt when I hike, usually that’s enough to keep me warm.
I also usually throw in a thin windbreaker packed down in a dry bag if I know that there is potential for rain, moisture, or wind. This outer shell can help keep the layers underneath warm and dry.
And I ALWAYS pack an extra pair of merino wool hiking socks. Whether or not you are hiking in cold weather, it’s always nice to have a pair of dry socks in case the ones you’re wearing get wet from sweat, slogging through rivers or puddles, or if you find snow on the trail that gets into your boots.
Keeping Your Core Temperature
It is critical to keep your core warm, When the body goes into a hypothermic state, its natural self-preservation response is to stop sending blood out to your extremities to protect your vital organs from the cold. It is unlikely that you will end up in a hypothermia situation on your day hike, but the premise remains the same. Keep your heart warm, and it will help maintain your whole-body temperature.
Warming Your Extremities for Comfort
If you’re one of those people that can’t stand cold hands and feet, you may want to look into ways to keep those areas warm for your own comfort and enjoyment on your day hike in cold climates. Merino wool socks are my go-to no matter the weather because it helps regulate your body temperature. When it’s cold, the natural bends in its fibers trap air, insulating you. When it’s warm outside, it wicks sweat quickly away from the skin, helping to keep you cool and dry.
To keep your fingers warm, try using mittens instead of gloves because it’s easier for your body to keep your fingers warm together, versus individually in a glove. You can also try an electric hand warmer, like the KARECEL rechargeable hand warmers that will give you 4-8 hours of warmth depending on the setting.
Emergency Blanket vs. a Bivvy
A lot of times you’ll see people pack the cheap foil blankets that you can get pretty much anywhere that you can buy hiking gear. These are not always effective in trapping warm air near your body because it’s a loose sheet and it can easily tear. They do have other handy uses though, like adding windproof protection to your clothing layers, serve as a makeshift emergency signal with it’s reflective side, and can be a makeshift poncho if you run into unexpected rain.
For a more reliable insulation blanket, buy an emergency bivvy bag, which will reflect 90% of your body heat and zip up around you to keep that warmth in. A bivvy, or bivouac, is an emergency shelter, with the term originating from WWII army slang for their temporary shelter for troops. Depending on the brand and type you get, they can be tear-proof, wind-proof and quieter than the foil blanket. For a few bucks more, go with the bivvy bag instead.