Cossatot Reefs
Tonight: low 64 °F, some dew.
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 74°F. The coldest are in January, when 1 night in 10 drops to 24°F. Frost is common in January, February and December.
- Jan34°F 24°FBag comfortable to 25°F · frost 40% · rain or snow 31% of days
- Feb38°F 26°FBag comfortable to 25°F · frost 25% · rain or snow 43% of days
- Mar46°F 36°FBag comfortable to 35°F · frost 4% · rain or snow 41% of days
- Apr53°F 43°FBag comfortable to 45°F · frost 0% · rain or snow 39% of days
- May62°F 53°FBag comfortable to 55°F · frost 0% · rain or snow 41% of days
- Jun70°F 64°FBag comfortable to 65°F · frost 0% · rain or snow 33% of days
- Jul74°F 70°FBag comfortable to 70°F · frost 0% · rain or snow 36% of days
- Aug73°F 69°FBag comfortable to 70°F · frost 0% · rain or snow 34% of days
- Sep (this month)69°F 60°FBag comfortable to 60°F · frost 0% · rain or snow 24% of days
- Oct58°F 46°FBag comfortable to 45°F · frost 0% · rain or snow 27% of days
- Nov45°F 34°FBag comfortable to 35°F · frost 7% · rain or snow 26% of days
- Dec39°F 29°FBag comfortable to 30°F · frost 23% · rain or snow 30% 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
Good nightFriday, September 25, 10 p.m. to 7 a.m.
Your selected gear looks warm enough
About 27 °F to spare at the coldest hour.
This is based on typical values for the gear types you picked, so treat it as an estimate.
Your night
- 10 p.m. until morningComfortableAir around you 76 to 66°F, some dew from 2 a.m.
Every hour
- 10 p.m.76°Fcomfortable
- 11 p.m.70°Fcomfortable
- midnight74°Fcomfortable
- 1 a.m.74°Fcomfortable
- 2 a.m.68°Fcomfortable, some dew
- 3 a.m.72°Fcomfortable
- 4 a.m.71°Fcomfortable
- 5 a.m.69°Fcomfortable
- 6 a.m.67°Fcomfortable
- 7 a.m.66°Fcomfortable
This spot sits about 23 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-5).
What works tonight
The gear this night calls for, for someone who sleeps like you.
- You have this
Sleeping bag
Comfort 65°F or colder
Usually sold as a 56° bag. The number in a bag's name is the limit, not the comfort.
- You have this
Underneath you
R1 or more
The R-value says how well a pad keeps the cold ground out.
Before you sleep
- 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.
- 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
- 64°F
- Warmth your shelter holds
- +2 °F
- Air around you
- 66°F
- Your bag's comfort rating
- 39°F
- Your comfort limit
- 39°F
27 °F to spare, so warm enough.
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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