Et0 Hargreaves
by Farm & Garden Calc in Weather & location
Hargreaves reference evapotranspiration (mm/day) from max and min temperature, latitude and day of year.
https://agri-calc.x402tookit.com/et0-hargreaves- Price
- $0.02
- per call in USDC
- Uptime
- 64.3%
- last 30 days
- Response time
- 526 ms
- 579 ms slowest 5%
- Last check
- Passed
- 1 h ago, next in 5 h
Reliability
Status and outage history · Atom feed · Watch with other listings
How to call it
GET https://agri-calc.x402tookit.com/et0-hargreaves
Each call costs $0.02 in USDC on Polygon, paid with the request over x402.
Run a free test callOne unpaid request, the way an agent sends it. You see the payment challenge it gets back. Nothing is charged.
Example request
From the listing.
GET https://agri-calc.x402tookit.com/et0-hargreaves?dayOfYear=246&latitude=-20&tmaxC=21.5&tminC=12.3Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
dayOfYear | number | Yes | Day of year, 1 to 366 |
latitude | number | Yes | Latitude in degrees, -90 to 90 (south negative) |
tmaxC | number | Yes | Daily maximum air temperature, Celsius |
tminC | number | Yes | Daily minimum air temperature, Celsius |
Example response
The provider's example. We can't check it without paying.
{
"asOf": "2026-10-11T23:40:36.036Z",
"degraded": false,
"disclaimer": "Screening signal computed from the named public source. Not financial, legal or investment advice; provided as is. Verify at the source before acting.",
"et0InchesPerDay": 0.12519,
"et0MmPerDay": 3.1797,
"extraterrestrialRadiationMJm2Day": 32.194,
"extraterrestrialRadiationMmDay": 13.135,
"meanTempC": 16.9,
"notChecked": [
"wind, humidity and cloud cover (Hargreaves uses temperature only, so it is rougher than Penman-Monteith)",
"local calibration (accuracy is worse on coastal and humid sites)",
"…1 more"
],
"reasons": [
"ET0 = 0.0023 x (Tmean + 17.8) x sqrt(Tmax - Tmin) x Ra, with Ra the extraterrestrial radiation in mm/day equivalent.",
"A rough estimate from temperature alone; use it for planning, not scheduling to the millimetre."
],
"source": "computed locally (Hargreaves and Samani 1985 with FAO-56 eq. 21 extraterrestrial radiation)",
"summary": "Reference ET0 about 3.18 mm/day (0.125 in/day) at latitude -20, day 246.",
"tempRangeC": 9.2,
"verdict": "ET0_COMPUTED"
}Call it from code
The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.02.
curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://agri-calc.x402tookit.com/et0-hargreaves?dayOfYear=246&latitude=-20&tmaxC=21.5&tminC=12.3'
# 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://agri-calc.x402tookit.com/et0-hargreaves?dayOfYear=246&latitude=-20&tmaxC=21.5&tminC=12.3' \
| grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decodeJavaScript: pay and call
// 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%2Fagri-calc.x402tookit.com%2Fet0-hargreaves
const res = await pay("https://agri-calc.x402tookit.com/et0-hargreaves?dayOfYear=246&latitude=-20&tmaxC=21.5&tminC=12.3");
console.log(res.status, await res.text());Python: pay and call
# 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://agri-calc.x402tookit.com/et0-hargreaves?dayOfYear=246&latitude=-20&tmaxC=21.5&tminC=12.3")
print(res.status_code, res.text)Security scan
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Recent checks
| When | Result | HTTP | Time | Price |
|---|---|---|---|---|
| 1 h ago | Passed | 402 | 537 ms | $0.02 |
| 15 h ago | Passed | 402 | 552 ms | $0.02 |
| 47 h ago | Expected HTTP 402, got 530 | 530 | 80 ms | - |
| 3 days ago | Expected HTTP 402, got 530 | 530 | 107 ms | - |
| 4 days ago | Expected HTTP 402, got 530 | 530 | 93 ms | - |
Show 9 older checks
| 5 days ago | Expected HTTP 402, got 530 | 530 | 189 ms | - |
| 5 days ago | Expected HTTP 402, got 530 | 530 | 169 ms | - |
| 5 days ago | Passed | 402 | 579 ms | $0.02 |
| 5 days ago | Passed | 402 | 571 ms | $0.02 |
| 6 days ago | Passed | 402 | 188 ms | $0.02 |
| 6 days ago | Passed | 402 | 526 ms | $0.02 |
| 6 days ago | Passed | 402 | 493 ms | $0.02 |
| 6 days ago | Passed | 402 | 491 ms | $0.02 |
| 7 days ago | Passed | 402 | 177 ms | $0.02 |