weather.forecast

Official US weather forecast for a coordinate (US land + territories). Pass lat + lon. Returns the National Weather Service forecast as a list of periods — by default ~7 days of day/night periods; pass hourly=true for an hour-by-hour forecast. Each period gives the temperature + unit, wind speed/direction, chance of precipitation, and a short + detailed forecast, plus the resolved city/state and issuing office. Source: US National Weather Service (api.weather.gov), public domain. For active warnings use weather.alerts.

price
$0.0014 USDC per call
method
GET/api/weather/forecast
payment
x402 v2 · USDC on Base (EIP-3009) or Solana (SPL transfer)
auth
None. Sign the payment, retry with PAYMENT-SIGNATURE.

Overview

The weather forecast API returns the official US National Weather Service forecast for any coordinate — the same authoritative source that powers weather.gov, served as clean JSON for agents.

Pass a latitude and longitude and get back a list of forecast periods: by default about seven days of day/night periods, or set hourly=true for an hour-by-hour forecast. Each period includes temperature and unit, wind speed and direction, chance of precipitation, and a short and detailed forecast, plus the resolved city/state and the issuing NWS office. The data is US public domain, and there is no API key — an agent signs a sub-cent USDC payment per call and gets the forecast back. For active warnings and watches, pair it with the weather alerts endpoint.

Use cases

Parameters

NameTypeDescription
latrequirednumber
min -90 · max 90
lonrequirednumber
min -180 · max 180
hourlyboolean
limitinteger
min 1 · max 156

Code samples

cURLbash
# 1. Probe with no auth → 402 envelope with PaymentRequirements
curl -sS 'https://2s.io/api/weather/forecast?lat=-90&lon=-180&hourly=false&limit=1'

# 2. Sign + retry with PAYMENT-SIGNATURE:
curl -sS 'https://2s.io/api/weather/forecast?lat=-90&lon=-180&hourly=false&limit=1' \
  -H 'PAYMENT-SIGNATURE: <base64-json-payload>'

# Or use the canonical runner (handles probe → sign → retry):
#   EVM_PRIVATE_KEY=0x... node --env-file=.env.local \
#     --experimental-strip-types scripts/x402-pay.ts \
#     'https://2s.io/api/weather/forecast?lat=-90&lon=-180&hourly=false&limit=1'
TypeScript / Node — @2sio/sdktypescript
import { TwoS } from '@2sio/sdk'

const client = new TwoS({
  privateKey: process.env.EVM_PRIVATE_KEY as `0x${string}`,
})

const result = await client.weather.forecast({
  "lat": -90,
  "lon": -180,
  "hourly": false,
  "limit": 1
})

console.log('endpoint:', result.endpoint)
console.log('cost:', result.costUsd, 'USDC')
console.log('tx:', result.settlement?.txHash)
console.log('data:', result.data)
Python — 2siopython
import os
from twosio import TwoS

client = TwoS(private_key=os.environ["EVM_PRIVATE_KEY"])

result = client.weather.forecast(lat=-90, lon=-180, hourly=False, limit=1)

print("endpoint:", result.endpoint)
print("cost:", result.cost_usd, "USDC")
print("tx:", (result.settlement or {}).get("tx_hash"))
print("data:", result.data)
MCP — Claude Desktop / AgentKit / any MCP hostjson
// 1. Add @2sio/mcp to your MCP host config (Claude Desktop example below).
//    EVM_PRIVATE_KEY funds x402 payments per call.

// claude_desktop_config.json
{
  "mcpServers": {
    "2sio": {
      "command": "npx",
      "args": ["-y", "@2sio/mcp"],
      "env": { "EVM_PRIVATE_KEY": "0x..." }
    }
  }
}

// 2. Once the server is running, agents call this tool via standard MCP:

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "weather.forecast",
    "arguments": {
      "lat": -90,
      "lon": -180,
      "hourly": false,
      "limit": 1
    }
  }
}

Response

FieldTypeDescription
okboolean
one of: true
itemsarray
totalintegerTotal matching rows upstream; null when unknown.
sourceobject
metaobject
Example response datajson
{
  "ok": true,
  "items": [
    {
      "name": "example",
      "startTime": "example",
      "endTime": "example",
      "isDaytime": false,
      "temperature": 1,
      "temperatureUnit": "example",
      "windSpeed": "example",
      "windDirection": "example",
      "precipProbabilityPct": 1,
      "shortForecast": "example",
      "detailedForecast": "example"
    }
  ],
  "total": 1,
  "source": {
    "provider": "example",
    "url": "example",
    "license": "example"
  },
  "meta": {
    "location": "example",
    "forecastOffice": "example",
    "updated": "example",
    "periods": 1
  }
}

FAQ

Where does the weather forecast data come from?
The US National Weather Service (api.weather.gov), which is public domain. The endpoint returns the official NWS forecast for the coordinate you pass.
Does the weather API cover hourly forecasts?
Yes. By default you get ~7 days of day/night periods; pass hourly=true for an hour-by-hour forecast. Use the limit parameter to cap the number of periods returned.
Does it cover locations outside the United States?
No — coverage is US land and territories, matching the National Weather Service. For non-US coordinates, geocode first and use a global source.
Do I need an API key to use the forecast API?
No. weather.forecast is x402-native — there is no signup and no API key. Your client makes the call, receives a 402 with payment requirements, signs a USDC payment, and retries. Funds come from a wallet you control.
How much does the forecast API cost?
$0.00144 USDC per call, charged per request. There are no monthly fees, seats, or minimums — you pay only for the calls you make.
Can I try the forecast API for free first?
Yes. Add ?trial=1 (or the header X-2s-Trial: 1) to get a free real call per endpoint per hour, so you can verify the response shape before wiring payment.
Which networks and tokens are supported?
USDC on Base (via EIP-3009 transferWithAuthorization) or Solana (SPL transfer), using the open x402 payment protocol.
How do I call weather.forecast from an AI agent or MCP host?
Use @2sio/sdk (TypeScript), 2sio (Python), or the @2sio/mcp server for any MCP host — each handles the probe → sign → retry loop for you. See the code samples on this page.

Discovery

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