Swan Lake Cabin Seward
Tonight: low 40 °F, some dew, rain likely, strong gusts.
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 47°F. The coldest are in December, when 1 night in 10 drops to -3°F. Frost is common in January, February, March, April, May, September, October, November and December.
- Jan15°F -3°FBag comfortable to 0°F · frost 100% · rain or snow 48% of days
- Feb15°F 0°FBag comfortable to 0°F · frost 100% · rain or snow 47% of days
- Mar16°F 1°FBag comfortable to 0°F · frost 100% · rain or snow 39% of days
- Apr24°F 14°FBag comfortable to 15°F · frost 97% · rain or snow 39% of days
- May30°F 25°FBag comfortable to 25°F · frost 63% · rain or snow 47% of days
- Jun41°F 36°FBag comfortable to 35°F · frost 2% · rain or snow 47% of days
- Jul47°F 41°FBag comfortable to 40°F · frost 0% · rain or snow 46% of days
- Aug45°F 40°FBag comfortable to 40°F · frost 0% · rain or snow 54% of days
- Sep (this month)38°F 31°FBag comfortable to 30°F · frost 13% · rain or snow 59% of days
- Oct28°F 17°FBag comfortable to 20°F · frost 79% · rain or snow 51% of days
- Nov16°F -1°FBag comfortable to 0°F · frost 98% · rain or snow 49% of days
- Dec12°F -3°FBag comfortable to 0°F · frost 100% · rain or snow 53% 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 nightFriday, September 25, 10 p.m. to 7 a.m.
Your setup looks borderline for this night
You may feel chilly from around 5 a.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 5 a.m.ComfortableAir around you 48 to 43°F, some dew, strong gusts, rain likely (up to 51 mph).
- 5 a.m. until morningChilly. Add a layerAir around you 42°F, some dew, strong gusts, rain likely (up to 45 mph).
Every hour
- 10 p.m.48°Fcomfortable, some dew, strong gusts, rain likely
- 11 p.m.47°Fcomfortable, some dew, strong gusts, rain likely
- midnight46°Fcomfortable, some dew, strong gusts, rain likely
- 1 a.m.46°Fcomfortable, some dew, strong gusts, rain likely
- 2 a.m.45°Fcomfortable, some dew, strong gusts, rain likely
- 3 a.m.43°Fcomfortable, some dew, strong gusts, rain likely
- 4 a.m.43°Fcomfortable, some dew, strong gusts, rain likely
- 5 a.m.42°Fchilly, some dew, strong gusts, rain likely
- 6 a.m.42°Fchilly, some dew, gusty, rain likely
- 7 a.m.42°Fchilly, some dew, gusty, rain likely
This spot sits about 90 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-8).
What works tonight
The gear this night calls for, for someone who sleeps like you.
- You have this
Sleeping bag
Comfort 40°F or colder
Usually sold as a 31° 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.
Before you sleep
- Put on a warm layer and a hat before about 5 a.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.
- Stake out every guyline and point the low, narrow end of the tent into the wind.
- Gusts get strong during the night. Do not pitch or park under dead trees or big dead branches.
- Rain is possible from about 10 p.m. Keep the rain fly on and bring shoes and packs inside.
- Bring shoes, clothes and electronics inside. Anything left out will be wet by morning.
How we estimated this
At the coldest hour (7 a.m.):
- Outside at your spot
- 40°F
- Warmth your shelter holds
- +2 °F
- Air around you
- 42°F
- Your bag's comfort rating
- 39°F
- Cold ground through what you lie on
- +4 °F
- Your comfort limit
- 43°F
1 °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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