How do I check the heat and wind on a race route with AI?
Updated
With the livedot connector in ChatGPT or Claude, ask “What will the weather be like for the NYC Marathon?” Within 10 days of the start you get the live forecast along the course, timed to when runners reach each stretch; further out, 10 years of weather on that date, labelled as history.
Ask it
Add the livedot connector first: it takes a minute. See using RunFast in ChatGPT and Claude.
Then name the race:
- “What will the weather be like for the NYC Marathon?”
- “Will it be hot for the Comrades demo?”
- “Fly the NYC Marathon course.”
You get the answer in words, and a map of the course coloured by how hard the weather makes each stretch: Ideal, A little slower, Hard or Very hard.
Forecast or history
The answer depends on how far away the start is, and it always says which one you’re reading.
| When | What you get | Labelled |
|---|---|---|
| Within 10 days | The live forecast from Apple Weather, timed to when runners reach each stretch. | “Forecast from Apple Weather, timed to the course” |
| More than 10 days out | What the course has had on this date over 10 years of weather records (Copernicus ERA5, 2015–2024). | “Based on 10 years of weather on this date … not a forecast” |
From 10 days out the forecast takes over by itself. See no forecast yet.
What’s in the answer
The same numbers as RunFast, because they come from the same engine:
- The rating, Good, Fair or Tough, and with a forecast, the reason;
- the temperature at the start and the finish;
- heat stress, from Low to Extreme, with the highest WBGT on the course. See heat stress levels;
- the weather cost, such as “Weather costs about 13 min”, with a forecast. See what the weather cost means;
- the hardest stretch, such as “Hardest from km 6 to 90”;
- rain: the amount, or for history, how many days in 10 had rain;
- the timing it used, such as “Timed for a runner at 6:00 per km”.
Which routes it can read
The connector reads only what’s public on livedot:
- races on a club’s or organiser’s page that start in the next 14 days;
- races with a livedot weather preview, such as the NYC Marathon;
- the Comrades demo, any day.
It can’t read your own runs. For a route of your own, or the weather at your own pace and start time, use Map your run: drop in your GPX, set your pace, and RunFast times every kilometre to you. For the Comrades, Berlin, London and Boston, Map your run also shows the real weather on past race days. See race-day weather history.
Good to know
- The answer is timed for the pace it names, not yours. Your own pace changes when you reach the hot part of the day.
- If several races match, the assistant asks which one you mean.
- Ask in miles and °F, or km and °C, and the answer follows.