Fontainebleau Climbing Conditions

updated 21:106
A satellite spotted a fire near Bois le Roi at 04:15. It may already be out. Stay clear, and call 18 or 112 if you see smoke.Fire spotted · near Bois le Roi, 04:15NASA satellite
Moderate fire danger today today, from Météo-France: All fires are forbidden in the forest..Moderate fire danger today · All fires are forbidden in the forest.Météo-France
TemperatureOvercast, air temperature14° → 29°
FRICTION
6/ 10AverageAverage
VERDICT:Poor friction until 10:00, then good friction
  • ·Best session: midday–evening
  • ·Dry. Last rain was 1.6 mm, a day ago.
  • ·Dry air, 9° above the dew point. Holds should feel dry.
Simulated view west over the forest, drawn from the current weather: overcastSimulated view

Today

Sunrise 07:4507:45Sunset 19:3219:32
4
6
6
6
Some cloudClearOvercastOvercast, windy
Air17°25°28°28°
Humidity80%52%39%36%
Rainnonenonenonenone
Wind 11 13 17 17
Dryness98%99%100%100%
Dew point13°14°13°11°
Cloud68%20%91%88%

Where it rained

Loading the map…

Next 48 hours

Hour by hour for the next 48 hours: the score, the sky, and the rain.
TodayTomorrow

Tomorrow

Morngreasy
Middry
Afthot
Everaining
6
6
6
4
OvercastOvercastOvercastRain
Air21°24°26°23°
Humidity65%56%50%75%
Rainnonenonenone3.5 mm
Wind 17 14 17 15
Dryness100%100%100%87%
Dew point14°15°15°18°
Cloud100%98%99%100%

Next 6 days

Wedraining
Thugreasy
Fridry
Satdry
Sundry
Mondry
6
7
7
7
7
7
RainSome cloudSome cloudOvercastSome cloudSome cloud
Air23°17°17°18°8°8°
Humidity62%77%63%57%70%70%
Rain3.5 mmnonenonenonenonenone
Wind 16 12 8 8 0 0
Dryness97%71%93%98%96%94%
Dew point15°13°10°9°0°0°
Cloud99%63%61%91%50%50%

About bleau.today

bleau.today tells boulderers whether the sandstone at Fontainebleau is dry, and when the friction will be good. It scores every hour, from yesterday to seven days ahead, for the whole forest and for five areas: Fontainebleau, Bois-le-Roi, Milly (Trois Pignons), Nemours and Buthiers.

Every hour it reruns a physical model of the rock on the latest forecasts from Météo-France (ARPEGE, AROME) and the German weather service (ICON), via Open-Meteo. For hours already past, the rain comes from Météo-France's own gauges. The model follows the temperature of the rock face, a fast surface layer of moisture and a slow core, the dew point, the humidity of the air and the wind. Wet Bleau sandstone breaks, so rock too wet to climb gets no score at all.

How the score works →Public API →

At a glance

CoversThe whole forest, and 5 areas scored apart
ForecastHour by hour, from yesterday to 7 days ahead
UpdatedEvery hour
Weather dataMétéo-France and ICON models via Open-Meteo; measured rain from Météo-France gauges
AlertsMétéo-France weather warnings, forest fire danger, NASA satellite fire detections
Score
Humidity94% → 36%
WindWind from SSE, 9 then 18 km/h9 → 18 km/h
Last rain1.6mm 1d ago
Next rain11mm in 22h
Thursday
10°15°20°25°30°
212223000102030405060708091011121314151617181920212223000102030405060708091011121314151617181920
Humidity %474752647679756666656767666360575551504959739295959496979594949494939596969692867873686159515561
Friction out of 10 for every hour; none when the rock is too wet
CostFree, no account
LanguagesEnglish and French
APIPublic, read-only JSON

Questions climbers ask

Is Fontainebleau dry enough to climb today?

The verdict at the top of this page answers it for the whole forest, or for one area once you pick it. It is rebuilt every hour from the latest forecast and, for the hours already past, from measured rain. When the rock is too wet it says so, rather than giving a low score.

How long does Fontainebleau sandstone take to dry after rain?

It depends on how much fell, and on the sun, the wind and the humidity since, which is why the model follows the surface and the core of the rock apart. A light shower on an exposed block can be gone within hours. A real soaking takes a day or more to leave the core, and drying slows down as the rock dries.

Why not climb on wet sandstone?

Wet Bleau sandstone is weaker: holds snap, edges crumble, and a broken hold never grows back. That is why wet rock is a gate here and not a penalty. Past the threshold, no temperature or breeze can make it climbable.

What gives the best friction at Bleau?

Cold rock well above the dew point, dry air and a breeze. Colder is better for friction right down past freezing; above about 26 °C the heat drags it down however dry the day is. Comfort is scored separately, so a freezing day loses a few points without pretending the friction is bad.

Which areas are covered?

Fontainebleau (Bas Cuvier, Apremont, Franchard), Bois-le-Roi (Rocher Canon), Milly and the Trois Pignons (95.2, Cul de Chien, Roche aux Sabots), Nemours (Dame Jouanne, Maunoury) and Buthiers. Each is scored twice, for its open blocks and for its wooded ground, and the areas are kept apart because one shower can soak Milly and miss Nemours.