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@xmayeth built a Claude Code bot that pulled live METAR from the settlement…

2026-06-20 · 15:40 UTC ·@xmayeth ·2 min read

Brief

Trader @xmayeth automated a simple edge on Polymarket by feeding live METAR from the settlement station into a Claude Code bot; late-afternoon temperatures (highs usually 2–4pm local) often already determine resolution while markets lag on morning forecasts. The bot buys underpriced favorites (e.g., 84–85°F at ~68c) when estimated probability exceeds ~90% (and price <80c), yielding ~$900 in a day.

Why it matters

@xmayeth built a Claude Code bot that pulled live METAR from the settlement station (e.g., KLGA) to trade Polymarket temperature markets, netting about $900 in one day.

Key details

  • Edge comes from timing: daily high usually occurs between 2–4pm local, so late-day METAR often pins the resolution while markets still price on morning forecasts; the bot buys baskets priced ~70–80c when it estimates prob >0.9 (rule: if prob > 0.9 and price < 0.8 and hours_left < 18 -> enter).
  • Live example: at ~3:40pm an NYC station read ~84°F with maybe 1°F left; the 84–85°F basket traded ~68c while it would resolve at $1, so the bot captured that mispricing and then continues to scoop locked baskets through the evening with light hedges.
Source evidence

A follower DM'd me a weather edge on Polymarket.
Built a bot around it - $900 in a day.

His whole message was one line. "Look at the temperature markets. Wait for the last hours before close, watch the live station, buy the underpriced favorite."

That was it, nothing else.

Sounded too easy.
If it actually worked like that, the gap would've been gone already.

But I had a free morning. Threw together a bot in Claude Code, plugged in METAR, left it running. Checked back a few hours later and it had already grabbed a couple of baskets cheap and was sitting green.

By resolve I was up $900.

That's when I actually dug into why something this simple isn't already picked clean.

It's all about timing.

The daily high almost always lands between 2 and 4pm local. After that the temperature isn't climbing anymore, it's falling. So by end of day the outcome is basically settled - the day physically can't get any hotter.

Which means the live station reading - METAR from the exact airport the market settles on (KLGA and so on) - already tells you what the resolution temp is going to be, with pretty high confidence.

The market doesn't.

Half of it is still sitting on the morning forecast, and the lazier bots can't be bothered to reprice on fresh data.

So the basket that already won is still hanging at 70-80c, while the real probability is way past that.

The bot just hunts for exactly that:

  1. pulls live METAR from the settlement station
  2. takes the current high + how much the day can still realistically add
  3. if that clears ~90% and the price is under 80c, it buys

  4. light hedge, only if the book flips hard

    Roughly what's under the hood:
    if prob > 0.9 and price < 0.8 and hours_left < 18 -> enter

What it looks like live (rough, from memory on one NYC market): around 3:40pm the station's already at ~84F, maybe a degree left in the day.

The 84-85 basket is going for about 68c. Resolves at 84 -> a dollar.

Edge caught a good four hours before the high locked in for good.

Now I just leave the bot running and watch it scoop up locked baskets at 70c through the evening.

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