Isa Atmosphere

{
  "altitudeFt": 10000,
  "asOf": "2026-10-11T14:44:08.573Z",
  "degraded": false,
  "densityRatio": 0.7385,
  "disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
  "isaDensityKgM3": 0.9046,
  "isaDeviationC": 9.81,
  "isaPressureHpa": 696.82,
  "isaPressureInHg": 20.577,
  "isaTemperatureC": -4.81,
  "isaTemperatureF": 23.34,
  "layer": "troposphere (6.5 C per km, 1.98 C per 1000 ft)",
  "notChecked": [
    "the real atmosphere, which differs from the ISA by tens of degrees and by humidity",
    "geopotential versus geometric altitude, which differ by under 0.3% below 65,000 ft",
    "…1 more"
  ],
  "oatC": 5,
  "reasons": [
    "Below 36,089 ft the temperature falls 6.5 C per 1000 m (about 1.98 C per 1000 ft) from 15 C; above it the temperature holds at -56.5 C.",
    "ISA deviation = actual temperature - ISA temperature at the same pressure altitude."
  ],
  "ruleOfThumbIsaTempC": -5,
  "source": "computed locally",
  "speedOfSoundKt": 638.3,
  "summary": "At 10000 ft the standard atmosphere is -4.8 C, 696.82 hPa (20.577 inHg), density 0.9046 kg/m3 (73.8% of sea level). 5 C is ISA +9.8.",
  "verdict": "WARMER_THAN_ISA"
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://aviation-calc.x402tookit.com/isa-atmosphere?altitudeFt=10000&oatC=5'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - 'https://aviation-calc.x402tookit.com/isa-atmosphere?altitudeFt=10000&oatC=5' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.02 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.02" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.02 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Faviation-calc.x402tookit.com%2Fisa-atmosphere
const res = await pay("https://aviation-calc.x402tookit.com/isa-atmosphere?altitudeFt=10000&oatC=5");
console.log(res.status, await res.text());

# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.02 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.02"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://aviation-calc.x402tookit.com/isa-atmosphere?altitudeFt=10000&oatC=5")
    print(res.status_code, res.text)