Lost Johnny Campground
Tonight: low 41 °F, heavy dew, breezy.
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 August, typically 51°F. The coldest are in February, when 1 night in 10 drops to -8°F. Frost is common in January, February, March, April, May, October, November and December.
- Jan20°F 1°FBag comfortable to 0°F · frost 99% · rain or snow 46% of days
- Feb16°F -8°FBag comfortable to -5°F · frost 99% · rain or snow 56% of days
- Mar23°F 11°FBag comfortable to 10°F · frost 96% · rain or snow 49% of days
- Apr28°F 16°FBag comfortable to 15°F · frost 81% · rain or snow 50% of days
- May35°F 29°FBag comfortable to 30°F · frost 27% · rain or snow 45% of days
- Jun43°F 36°FBag comfortable to 35°F · frost 0% · rain or snow 42% of days
- Jul51°F 45°FBag comfortable to 45°F · frost 0% · rain or snow 17% of days
- Aug51°F 45°FBag comfortable to 45°F · frost 0% · rain or snow 20% of days
- Sep (this month)45°F 36°FBag comfortable to 35°F · frost 3% · rain or snow 31% of days
- Oct33°F 23°FBag comfortable to 25°F · frost 44% · rain or snow 42% of days
- Nov26°F 15°FBag comfortable to 15°F · frost 82% · rain or snow 55% of days
- Dec21°F 6°FBag comfortable to 5°F · frost 97% · rain or snow 56% 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
Worth a lookFriday, September 25, 10 p.m. to 7 a.m.
Your setup looks borderline for this night
You may feel chilly from around midnight.
The cold comes from underneath: your pad does not insulate enough from the ground.
Best change
Add insulation underneath until you have about R1.5 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 midnightComfortableAir around you 44 to 43°F, heavy dew, gusty from 11 p.m. (up to 34 mph).
- midnight to 2 a.m.Chilly. Add a layerAir around you 42 to 41°F, heavy dew, gusty (up to 30 mph).
- 2 a.m. to 5 a.m.ComfortableAir around you 49 to 45°F, gusty from 3 a.m. (up to 31 mph).
- 5 a.m. to 6 a.m.Chilly. Add a layerAir around you 41°F, some dew.
- 6 a.m. to 7 a.m.ComfortableAir around you 41°F.
- 7 a.m. until morningChilly. Add a layerAir around you 40°F, some dew.
Every hour
- 10 p.m.43°Fcomfortable, heavy dew
- 11 p.m.44°Fcomfortable, heavy dew, gusty
- midnight41°Fchilly, heavy dew, gusty
- 1 a.m.42°Fchilly, heavy dew, gusty
- 2 a.m.49°Fcomfortable
- 3 a.m.47°Fcomfortable, gusty
- 4 a.m.45°Fcomfortable, gusty
- 5 a.m.41°Fchilly, some dew
- 6 a.m.41°Fcomfortable
- 7 a.m.40°Fchilly, some dew
This spot sits about 49 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-6).
What works tonight
The gear this night calls for, for someone who sleeps like you.
- Missing
Sleeping bag
Comfort 35°F or colder
Usually sold as a 26° bag. The number in a bag's name is the limit, not the comfort.
- You have this
Underneath you
R1.5 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 midnight, 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.
- Your spot sits lower than the ground around it. On a clear, calm night cold air drains into spots like this, so expect it colder and wetter than the forecast. If you can, move a little higher up, away from the creek or valley floor.
- Stake out every guyline and point the low, narrow end of the tent into the wind.
- Bring shoes, clothes and electronics inside. Anything left out will be wet by morning.
- Open the tent vents and keep the door zip open a bit at the top. Some condensation inside is normal on a night like this, so bring a small towel to wipe it off.
How we estimated this
At the coldest hour (7 a.m.):
- Outside at your spot
- 41°F
- Warmth your shelter holds
- +2 °F
- Clear-sky cooling
- −1 °F
- Low spot
- −2 °F
- Air around you
- 40°F
- Your bag's comfort rating
- 39°F
- Cold ground through what you lie on
- +4 °F
- Your comfort limit
- 43°F
3 °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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