Castle Butte Lookout
Tonight: low 29 °F, frost likely, 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 July, typically 60°F. The coldest are in December, when 1 night in 10 drops to 11°F. Frost is common in January, February, March, April, October, November and December.
- Jan26°F 10°FBag comfortable to 10°F · frost 81% · rain or snow 51% of days
- Feb26°F 13°FBag comfortable to 15°F · frost 75% · rain or snow 66% of days
- Mar31°F 20°FBag comfortable to 20°F · frost 58% · rain or snow 56% of days
- Apr35°F 26°FBag comfortable to 25°F · frost 31% · rain or snow 51% of days
- May43°F 37°FBag comfortable to 35°F · frost 1% · rain or snow 48% of days
- Jun51°F 43°FBag comfortable to 45°F · frost 0% · rain or snow 39% of days
- Jul60°F 53°FBag comfortable to 55°F · frost 0% · rain or snow 10% of days
- Aug60°F 53°FBag comfortable to 55°F · frost 0% · rain or snow 13% of days
- Sep (this month)52°F 44°FBag comfortable to 45°F · frost 1% · rain or snow 28% of days
- Oct40°F 30°FBag comfortable to 30°F · frost 14% · rain or snow 45% of days
- Nov30°F 16°FBag comfortable to 15°F · frost 56% · rain or snow 56% of days
- Dec26°F 11°FBag comfortable to 10°F · frost 80% · rain or snow 61% 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 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 30°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.
Your night
- 10 p.m. to 1 a.m.Chilly. Add a layerAir around you 40 to 37°F, frost from 11 p.m., gusty (up to 29 mph).
- 1 a.m. to 2 a.m.Cold. Your setup is not warm enoughAir around you 35°F, frost.
- 2 a.m. to 3 a.m.Chilly. Add a layerAir around you 36°F, some dew.
- 3 a.m. until morningCold. Your setup is not warm enoughAir around you 34 to 31°F, frost.
Every hour
- 10 p.m.40°Fchilly, gusty
- 11 p.m.37°Fchilly, frost
- midnight37°Fchilly, frost, gusty
- 1 a.m.35°Fcold, frost
- 2 a.m.36°Fchilly, some dew
- 3 a.m.34°Fcold, frost
- 4 a.m.34°Fcold, frost
- 5 a.m.32°Fcold, frost
- 6 a.m.31°Fcold, frost
- 7 a.m.31°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
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.
- 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
- 29°F
- Warmth your shelter holds
- +2 °F
- Air around you
- 31°F
- Your bag's comfort rating
- 39°F
- Cold ground through what you lie on
- +8 °F
- Your comfort limit
- 47°F
16 °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.
Book or read more on Recreation.gov