weatherAI.io
The weather decision API

Don't send your users a forecast. Send them an answer.

One call tells your app, your team or your AI assistant whether and when to do something outside: a go or no-go, a score out of 100, the best hours and the risks.

Get your free API key See what's included
  • 1,000 free calls every month
  • Then £0.0012 per call, VAT included
  • No subscription

Try it now, no sign-up needed

30 activities, from running to crane lifts

5 industry packs

14 days ahead, anywhere in the world

Hour by hour scoring, with the reasons

One weather engine, six ways to use it

Every account gets all of it. No plans, no add-ons: you only ever pay per answer.

Ask about any day, get a clear answer

/v1/decide scores every hour for the activity and comes back with a verdict, the best windows, what could spoil it and a sentence you can show as it is.

  • Rain, wind, gusts, heat, frost, thunder, visibility, UV
  • Air quality, pollen (for hay fever) and sunshine where available
  • Daylight-aware, in the place's own time zone

How decisions work · Try the playground

Find the best day in the next two weeks

/v1/best-day ranks up to 14 days for one activity and picks the winner, with its best time. Comparing all of them still costs one call.

  • Plan the pour, the shoot, the harvest or the barbecue
  • Every day comes back with its own score and risks

Best day in the docs

Get told when the forecast changes its mind

Alerts watch a place for up to 7 days and email you, or call your webhook, the moment a day switches between go and no-go. We do the checking, every 1 to 12 hours, for free.

  • Only real changes: no daily digest to ignore
  • Signed webhooks to move jobs, warn crews or update bookings
  • Each notification is one call; the checks cost nothing

Set up an alert · Alerts in the docs

Use your own limits, not ours

Your crane's wind limit, your client's minimum temperature, your rule about lightning. Save them once as a custom rule and every answer, alert and widget follows it.

  • Hard limits on gusts, wind, rain, temperature, humidity, visibility and UV
  • Working hours and minimum window length
  • Free to save, up to 50 rules

Create a rule · Custom rules in the docs

Ask in plain words, in the AI tools you already use

weatherAI.io is an MCP server, so Claude, ChatGPT, Cursor, VS Code and Gemini CLI can use it directly. Sign in once; no code and no API key.

  • Decisions, best day, alerts and your custom rules as tools
  • OpenAPI and llms.txt for building your own agents

Connect your assistant

Show your visitors the outlook

A small go / no-go badge for your golf course, venue, beach hut or site, for today or the next few days. Paste two lines into WordPress, Wix, Squarespace or any page.

  • Uses your activity or custom rule, in your colours
  • At most 48 calls a day however many people see it
  • Only works on the websites you list

Create a widget · Widgets in the docs

What every account gets

Free to sign up. The same features whether you make ten calls or ten million.

Create your free account

Already use the API? See what each feature costs.

  • 1,000 free calls every month, renewed on the 1st
  • All 30 activities and all 5 industry packs
  • Decide and best day, up to 14 days ahead, worldwide
  • Up to 50 custom rules with your own limits
  • Up to 20 alerts by email or signed webhook
  • Up to 20 website widgets
  • MCP server for Claude, ChatGPT, Cursor and VS Code
  • Dashboard with usage by day and activity
  • Spending limit and low-credit emails
  • VAT receipts, and invoices for businesses

Ready-made for your industry

Activities tuned to how each trade actually works, from concrete curing temperatures to high-sided vehicle wind limits.

Construction Pouring concrete, Crane lifts, Roofing and work at height, Groundworks and excavation, Exterior painting, Outdoor work (building sites, landscaping, events crew) Events and hospitality Outdoor event (BBQ, party, wedding), Marquees, gazebos and temporary structures, Beer gardens, terraces and outdoor dining, Drone flying Agriculture Crop spraying, Harvesting and haymaking, Irrigation and watering, Drone flying, Outdoor work (building sites, landscaping, events crew) Logistics and field service Lorries, vans, coaches and towing, Driving and road trips, Field service and engineering, Outdoor work (building sites, landscaping, events crew) Energy Solar panel output (PV), Small wind turbine output, Field service and engineering, Roofing and work at height

Plus everyday activities: running, cycling, beach day, drying laundry outside, stargazing, hiking and hill walking, golf, tennis, padel and pickleball (outdoor), dog walking, gardening, fishing (from the shore or bank), sailing (leisure, inshore) and more. All activities

Works where you work

Your codeREST API with OpenAPI, from any languageDocs
AI assistantsClaude, ChatGPT, Cursor, VS Code, Gemini CLIConnect
WebhooksSigned alerts to your own systemsWebhooks
No-codeZapier, Make and n8n (coming soon)Integrations
Your websiteEmbeddable go / no-go widgetWidgets

Live in five minutes

  1. Sign up free and verify your email. Your key is ready straight away.
  2. Call one endpoint with a place, an activity and a date.
  3. Show the answer: the verdict, the best time and the summary sentence.
Get your free API key 
curl -H "X-API-Key: wai_…" \
  "https://api.weatherai.io/v1/decide?location=Leeds&activity=bbq&when=tomorrow"

{
  "verdict": "good",
  "score": 78,
  "best_windows": [
    { "start": "… 12:00", "end": "… 17:00", "score": 81 }
  ],
  "risks": [
    { "type": "rain", "severity": "moderate",
      "from": "… 18:00", "to": "… 21:00",
      "detail": "45% chance of rain" }
  ],
  "summary": "Good conditions for an outdoor event in Leeds;
              best 12:00–17:00. Watch for rain from 18:00."
}

We publish our track record

Every evening we record tomorrow's verdict for a fixed set of cities and check it against the weather that actually happened. All of it, misses included.

See the accuracy figures

Open about uptime

The API, website and alerts are checked from the outside every 5 minutes, with 90 days of history.

System status

No surprise bills

Prepaid credit, failed calls free, an optional monthly limit. When credit runs out, the API says so instead of charging you.

Pricing

Questions

How is this different from a weather API?

Weather APIs give you the data; weatherAI.io gives you the decision. There are no raw hourly tables to interpret: you get a verdict, a score, the best times and the risks for the thing your user wants to do.

What counts as a call?

Each successful /v1/decide or /v1/best-day answer is one call, and so is each alert notification and each widget refresh. Bad requests, unknown places and our own errors are free, and so are custom rules, alert checks, listing activities and checking your usage.

What happens after my free calls?

Paid calls come from prepaid credit at £0.0012 each, VAT included. Larger top-ups get bonus credit (+10% from £250, +20% from £1,000). When both run out the API answers 402 until you top up or the next month's free calls start.

Can my business pay by invoice?

Yes, for top-ups from £250. Add your company details, VAT number and purchase order reference, and pay by card or bank transfer within 14 or 30 days.

Can I use it from an AI agent?

Yes. Add our MCP server to Claude, ChatGPT, Cursor or any MCP client, or point your agent at our OpenAPI spec or llms.txt. The summary field is written to be read out as it is.

How accurate is it?

It's as good as the forecast it's based on, and forecasts are less certain further ahead. We publish how our day-ahead calls hold up on our accuracy page. Use it as a planning aid, never as the only check for anything safety-critical.

Start with 1,000 free calls a month

No card, no subscription. Upgrade by topping up when you need more.

Get your free API key See pricing