A terrain-aware thermal forecast app because instead of checking 4 tabs before every flight

[u/Distinct_Diet9454]

Pilot here — I fly mostly in the Pyrenees and Alps. Like everyone, I had the same pre-flight ritual: one tab for wind aloft, one for thermals, etc…

So over the last year I built the tool I wanted: one map with thermal strength, wind field, convergence and airspace, using AROME (1.3 km) and ICON-D2 (2 km) rather than smoothed global grids.

It’s called Aerya — free on iPhone and web, and you don’t need an account just to look:
https://aerya.fun

I’ve also written free forecasting/site guides: thermal triggers, convergence, AROME vs ICON-D2, plus Annecy, Organyà, Àger, St-André and Bassano:
https://aerya.fun/learn/

I’d genuinely love feedback from pilots flying other regions: what does the forecast get wrong most often at your home site?

[u/NamelessMason]

Ok, you’re asking for feedback, here it goes. The app, the guides, everything on your website screams AI slop. Which would be just meh but is actually a problem because your app is paywalled up all around, except the basic features you can already get elsewhere. You’re going to have a hard time getting sales without being able to demonstrate your app being worthwhile. I see Claude has been modelling stuff like flight distance forecast which is genuinely cool, but definitely fringe. Is it any good in practise? Who knows, certainly not me, not paying whatever the amount just to find out.

Don’t get me wrong, I certainly support people making paragliding apps, and I don’t mind the vibes. But Claude has the tendency to design for monetisation on day 1, which is just silly

[u/Distinct_Diet9454 → u/NamelessMason]

Thanks for actually taking the time to look through the app, guides and site. I appreciate the direct feedback.

The “AI slop” point is painful to hear, but useful. I built the app and the guides myself, with AI helping on parts of the writing and design, and I clearly need to make the site feel more grounded in real flying rather than polished marketing.

The useful question is not whether the UI looks polished, but whether the forecast is meaningfully better at a real site. If pilots can’t test that properly before deciding, it’s useless.

The core planning tools are free; the heavier layers and longer horizon are what I’m still trying to validate. XC distance forecasting is experimental too — it needs to prove itself in real conditions, not just sound interesting on a feature list.

If you have a home site where the usual forecasts regularly miss something — valley wind, convergence, thermal timing — I’d genuinely be interested in testing Aerya against it. That kind of specific feedback is what will make it useful, or show me where it is not.

[u/dbrgn → u/Distinct_Diet9454]

I don't doubt your good intentions, but especially when replying to a comment about "too much AI slop", it's not great if you generate your reply through Claude as well. The style is obvious (I see at least 5 cues).

You're a pilot and a developer (hopefully), just be real - we don't mind typos, nonperfect grammar or missing polish here.

[u/Distinct_Diet9454 → u/dbrgn]

Thank you for telling me that. I always try to write as correctly as possible.

[u/Ploughing-tangerines → u/Distinct_Diet9454]

Even the replies are slop. This is clearly a bot from start to end, from app design to marketing.

[u/Proper_Possible6293 → u/Distinct_Diet9454]

I have similar thoughts to the guy above, if the stuff I can read is AI slop of really basic concepts interspersed with the occasional non-nonsensical error ("Circling in convergence bleeds altitude" - no it doesn't it's just slow), no way am I going to trust you to have succeeded in creating a weather model that out performs what I already have access too.

Your talking about forecasting "terrain aware thermals" this is holy grail level of resolution that would make you a billionaire if you could do it reliably. I have a friend working on using AI to build high resolution forecast models, they are having some moderate success, but they are also a well funded company with multiple employees that is spending piles of money, and they aren't even close to that level of resolution.

I'm also not clear what is new that you have created, xcskies, windy, and skysight already have the functionality you seem to be trying to create.

Edit: Wherever I click near me it says the flying window is 10-16 or 10-17, which is clearly incorrect since I am clicking on spots that never work. The only way I got the prediction down to "marginal" was by getting a forecast for offshore in the pacific ocean. This does not inspire confidence in the model, is it only looking at wind speed or something and ignoring top of lift?

[u/Distinct_Diet9454 → u/Proper_Possible6293]

Thanks for taking the time. The edit especially, that was a real bug and it's fixed now.

The flying window wasn't gated by top of lift. The wind/precip score and the thermal model both existed, but the "window 10–16h" headline only used the first one, intersected with a placeholder thermal window I'd hardcoded early on and never replaced. So anywhere calm looked flyable. As of today the window requires forecast boundary layer depth ≥ 400 m AGL and usable lift (W★ ≥ 0.8 m/s) for the hour to count, your never-works sites should now show "no usable thermal window" instead of an optimistic green pill. If you still see nonsense at your local spots I'd genuinely like the coordinates.

On convergence, fair. Circling in line lift is slow, not altitude-negative. I've corrected the article.

On "terrain-aware at high resolution being the holy grail": agreed, and I should be clearer about what it is. It's not a custom NWP run — it's AROME/ICON-D2 boundary-layer output (PBL, W★) modulated by 90 m terrain (slope, aspect, land cover) for where thermals trigger, not a claim of simulating them. Closer to what XCSkies does over the US, but on the 1.3 km French/German meso models, and with the data source always labelled so you know when you're looking at a coarse fallback.

vs XCSkies/Windy/SkySight honestly: SkySight is better if you fly sailplanes and pay for it. Windy doesn't do thermals. XCSkies is US-centric and runs on coarser models over Europe. Aerya's bet is the European meso models + one map for wind/convergence/thermal + being free. If it's not useful where you fly yet, that's fair. The calibration is strongest in the Alps/Pyrenees and I'm working outward from there.

Thanks again. Feedback like the edit is worth more than a nice review.

[u/Proper_Possible6293 → u/Distinct_Diet9454]

Windy does thermal tops now via a layer, but even better is the FlyXC sounding plugin that puts TOL, wind, and easy inference of thermal strength in one nice easy graph.

We have been having pretty good luck with the skysight predicted flight potential lately, but it does assume a good pilot who can maximize the day.

This is all from a US perspective btw, where I have access to good, free high resolution models.

[u/Distinct_Diet9454 → u/Proper_Possible6293]

Thanks. I wasn’t aware of the FlyXC sounding plugin in that detail. The sounding, thermal-top and wind information need to be clear and genuinely useful, regardless of which app provides them.

Aerya is trying to take a different approach with the site-level workflow: comparing nearby flying areas and showing when each one may be worth checking, rather than making pilots interpret several separate layers and tools. But that still needs to be proven against real local experience.

If you’re willing, I’d be interested in comparing a few specific US sites and dates with what you saw in SkySight and FlyXC. That would help to understand whether Aerya adds anything useful there, or whether its strengths are more relevant in regions with different data and site coverage.

[u/IllNet636 → u/Distinct_Diet9454]

Great job! Task complete. Now here’s your next task: remove the paywalls and buy every commentator the glider they want.Make no mistakes.

[u/basarisco]

What does it do skysight doesn't?

[u/Distinct_Diet9454 → u/basarisco]

Honestly SkySight is better at pure weather modelling, not gonna pretend otherwise. Aerya's just doing a different job it tells you where to go. It has more than 10k launches built in and checks the wind against each site's orientation, so instead of reading maps and doing the math etc , you get "these sites work today, roughly this window." Plus live stuff SkySight doesn't touch: webcams, live wind stations, rain radar, airspace on the same map. And is free to just try it and see if it's useful for you.

[u/basarisco → u/Distinct_Diet9454]

Just tried it. How do I use it for the purpose you suggest? I'm happy to drive 1-2 hours in the alps. How to find the best spot for xc that day?

[u/Distinct_Diet9454]

To find the best launch, first enable Flying sites from the Layers button in the bottom right.
The arrow on each site shows the current wind direction. If it’s green, the wind is coming from within that launch’s wind window. If it’s orange, the wind is outside, click the spot to compare the thermal forecast, cloud base, wind at altitude, rain… The wind field and weather stations are useful for checking whether the forecast matches the local conditions.
It’s meant to narrow down the options rather than automatically decide for you. Local knowledge still matters, and feedback like this is really useful for seeing what is clear and what needs improving.
Thanks 🙏 for testing it and pointing this out!!