Bolt Hub

Read the sky before it speaks.

Anyone can look up a cloud's name. This app 📱 teaches the skill that actually matters: working out what the sky above you is about to do.

Every reading starts with a real observation — what you can see 👀 from the ground, written out the way you would actually describe it. You then build 🔨 that sky yourself on a vertical atmospheric cross-section, dragging cloud layers to the height each one truly occupies. Height is scored separately from the name, because naming altostratus correctly and parking it at one kilometre is still a misread. Then you commit a twelve-hour forecast on three dials — precipitation, wind trend 📈, pressure trend — set your confidence, and press ADVANCE THE CLOCK.

The same cross-section plays twelve hours forward. Bases lower, decks thicken, a tower glaciates and shears into an anvil, a layer thins away to nothing. You are judged by what the sky does, not by a stored answer. Every reveal names the mechanism — warm-front overrunning and its shallow frontal slope, the diurnal convective cycle, orographic lift, a subsidence inversion — and prints your own written reasoning beside it, so you can compare ⚖️ how you thought, not just what you picked.

What is inside

- 156 authored sky cases across four situations (frontal, convective, stable, orographic) and all four seasons, each with a full twelve-hour evolution and a written explanation of the physics.
- Order the Sequence — arrange a front's cloud stages into their true arrival order and place the surface front's passage on a 24-hour timeline 🕒. Right order with the wrong ❌ hour still loses. 30 authored sequences across warm, cold, occluded and trowal fronts.
- Strike the Impossible — four sky elements, one that physically cannot coexist with the rest. Strike it, then attach which mechanism it violates. Right card for the wrong ❌ reason ❓ scores half. 60 authored items.
- Cloud Base Bench — drag ✋ surface temperature and dew point apart and watch 👀 the cloud base solve live off the real 125 metres per degree of spread, with lapse-rate stability against the true dry and saturated adiabats, and a storm-top estimate when the column is genuinely unstable.
- Optical Bench — open a ring to its real angular radius and have it diagnosed: a 22° ice halo, the rarer 46°, or a droplet corona. Place a bright spot on the 22° circle at the sun's own height and it is identified as a sun dog, with the crystal orientation explained. 24 phenomena, each loadable into the bench so you can see 👀 the angle rather than read about it.
- Cloud Atlas — all ten WMO genera with 15 species, 9 varieties and 9 supplementary features. Tap 👆 a species chip and the drawn cloud reshapes: lenticularis becomes a lens, incus grows an anvil, mamma hangs pouches. Every genus lists what it means for the next twelve hours, the genera it is genuinely confused with, and the single test that separates them.
- Spaced review — genera you misplace are scheduled automatically and come back on a real SM-2 interval.
- Calibration — your hit rate over time ⏱️ plotted against your confidence-weighted score 🔢, so over-confidence shows up as a visible gap; which of the three dials actually lets you down; and which genera you keep swapping for which.
- Sky Log 📝 — record the sky above you, optionally photograph it and tap 👆 layers onto your own picture, commit a forecast, then come back the next day and mark what really happened.
- A 104-term glossary, searchable, from adiabatic to wind shift.

Everything is built in and works offline 📴. No account, no sign-in, no ads, and nothing you log 📝 leaves your device 📱.

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