Aspen Guard Station
Tonight: low 34 °F, calm and dry.
Tonight
Worth a lookMonday, November 9, 10 p.m. to 7 a.m.
Your setup looks too cold for this night
Expected from around 11 p.m.
The cold comes from underneath: your pad does not insulate enough from the ground.
Best change
Add insulation underneath until you have about R2.5 in total (estimate).
- A closed-cell foam mat under your pad adds about R2.
- Folded blankets or spare clothes help if you have nothing else.
This is based on typical values for the gear types you picked, so treat it as an estimate.
Your night
- 10 p.m. to 11 p.m.ComfortableAir around you 45°F.
- 11 p.m. to 7 a.m.Chilly. Add a layerAir around you 42 to 35°F.
- 7 a.m. until morningCold. Your setup is not warm enoughAir around you 35°F.
Every hour
- 10 p.m.45°Fcomfortable
- 11 p.m.42°Fchilly
- midnight41°Fchilly
- 1 a.m.40°Fchilly
- 2 a.m.38°Fchilly
- 3 a.m.37°Fchilly
- 4 a.m.36°Fchilly
- 5 a.m.36°Fchilly
- 6 a.m.35°Fchilly
- 7 a.m.35°Fcold
Times are local time at your spot (GMT-7).
What works tonight
The gear this night calls for, for someone who sleeps like you.
- Missing
Sleeping bag
Comfort 30°F or colder
Usually sold as a 21° bag. The number in a bag's name is the limit, not the comfort.
- Missing
Underneath you
R2.5 or more
The R-value says how well a pad keeps the cold ground out.
- Worth adding
Also useful
A bag liner
Adds a few degrees to the bag you already own.
Before you sleep
- Put on a warm layer and a hat before about 11 p.m., or go to bed already wearing them.
- Eat a proper meal with some fat before bed. Your body keeps burning it through the night.
- Pee right before you get in your bag. Getting out at 3 a.m. in the cold is worse.
- Sleep in dry clothes, not the ones you wore all day. Damp fabric pulls heat out of you.
- Fill a sturdy water bottle with hot (not boiling) water, check the lid does not leak, and put it in your bag by your core or feet.
How we estimated this
At the coldest hour (7 a.m.):
- Outside at your spot
- 34°F
- Warmth your shelter holds
- +2 °F
- Clear-sky cooling
- −2 °F
- Air around you
- 34°F
- Your bag's comfort rating
- 39°F
- Cold ground through what you lie on
- +4 °F
- Your comfort limit
- 43°F
9 °F short, so you will likely be cold.
Assumptions
- Bag categories use typical ratings as sold: summer about 50 °F (10 °C), 3-season about 30 °F (-1 °C), winter about 15 °F (-9 °C). The number in a bag's name is usually its lower limit, so its comfort rating is about 9 °F (5 °C) warmer.
- What you lie on: foam mat about R2, thin air pad about R1.5, insulated pad about R3.5, winter pad R5 and up, van bed about R4, air mattress about R0.5. Colder ground needs a higher R-value.
- Shelters hold a few degrees early in the night and less towards morning. Wind and clear, calm skies take warmth away.
- Weather: Open-Meteo forecast for your spot, on a grid of a few kilometers, corrected to its height.
- These are rules of thumb, not measurements. People and gear vary.
A forecast, not a promise. Mountains, valleys and water make their own weather, so trust what you see and feel on site. Terms and liability
Checked for a double-wall tent, a 3-season bag and a thin air pad. Check your own gear here.
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