Williwaw Campground

Girdwood, Chugach National Forest, Alaska

Tonight: low 23 °F, rain likely.

Nights by month

Night lows from 2016 to 2025: a typical night, and the cold one that comes 1 night in 10.

The mildest nights are in July, typically 54°F. The coldest are in December, when 1 night in 10 drops to 5°F. Frost is common in January, February, March, April, October, November and December.

Typical nightCold night (1 in 10)
  1. Jan25°F 6°FBag comfortable to 5°F · frost 77% · rain or snow 63% of days
  2. Feb24°F 10°FBag comfortable to 10°F · frost 89% · rain or snow 56% of days
  3. Mar26°F 12°FBag comfortable to 15°F · frost 77% · rain or snow 50% of days
  4. Apr34°F 24°FBag comfortable to 25°F · frost 37% · rain or snow 55% of days
  5. May38°F 35°FBag comfortable to 35°F · frost 3% · rain or snow 61% of days
  6. Jun48°F 41°FBag comfortable to 40°F · frost 0% · rain or snow 52% of days
  7. Jul54°F 49°FBag comfortable to 50°F · frost 0% · rain or snow 45% of days
  8. Aug52°F 48°FBag comfortable to 50°F · frost 0% · rain or snow 59% of days
  9. Sep46°F 38°FBag comfortable to 40°F · frost 2% · rain or snow 68% of days
  10. Oct36°F 22°FBag comfortable to 20°F · frost 36% · rain or snow 62% of days
  11. Nov (this month)25°F 8°FBag comfortable to 10°F · frost 69% · rain or snow 59% of days
  12. Dec22°F 5°FBag comfortable to 5°F · frost 81% · rain or snow 68% of days

| = 32°F

History: ERA5 and ERA5-Land reanalysis via Open-Meteo, corrected to the site's elevation. Bag rating: the comfort rating that keeps you warm in a tent on 9 of 10 nights that month.

Tonight

Rough nightSunday, November 8, 10 p.m. to 7 a.m.

Needs more warmth: sleeping bag

Your setup looks far too cold for this night

Expected from around 10 p.m.

Your sleeping bag is not warm enough for this night.

Best change

Use a sleeping bag rated comfortable at about 25°F or colder (estimate).

  • A liner or warm clothes add a few degrees, but not enough to close this gap on their own.

This is based on typical values for the gear types you picked, so treat it as an estimate.

  • Low outside23°F
  • Moisturedry
  • Windcalm
  • Rainrain likely, keep everything under cover

Your night

  1. 10 p.m. to 4 a.m.Chilly. Add a layerAir around you 37 to 35°F, rain likely from 1 a.m.
  2. 4 a.m. to 6 a.m.Cold. Your setup is not warm enoughAir around you 32 to 29°F, rain likely.
  3. 6 a.m. until morningDangerously coldAir around you 27 to 25°F.
Every hour
  • 10 p.m.36°Fchilly
  • 11 p.m.36°Fchilly, chance of rain
  • midnight37°Fchilly, chance of rain
  • 1 a.m.37°Fchilly, rain likely
  • 2 a.m.36°Fchilly, rain likely
  • 3 a.m.35°Fchilly, rain likely
  • 4 a.m.32°Fcold, rain likely
  • 5 a.m.29°Fcold, chance of rain
  • 6 a.m.27°Fdangerously cold
  • 7 a.m.25°Fdangerously cold

This spot sits about 30 m below the land around it. On clear, calm nights cold air pools here, so expect it colder and wetter than the forecast.

Times are local time at your spot (GMT-9).

What works tonight

The gear this night calls for, for someone who sleeps like you.

  • Missing

    Sleeping bag

    Comfort 25°F or colder

    Usually sold as a 16° bag. The number in a bag's name is the limit, not the comfort.

  • Missing

    Underneath you

    R3.5 or more

    The R-value says how well a pad keeps the cold ground out.

Before you sleep

  • Put on a warm layer and a hat before about 10 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.
  • Rain is possible from about 11 p.m. Keep the rain fly on and bring shoes and packs inside.
How we estimated this

At the coldest hour (7 a.m.):

Outside at your spot
23°F
Warmth your shelter holds
+2 °F
Air around you
25°F
Your bag's comfort rating
39°F
Cold ground through what you lie on
+8 °F
Your comfort limit
47°F

22 °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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