The Mercury Cup
A daily temperature-forecasting contest

How it works & FAQ

Won't everyone just copy from a weather app?

Even though you could, that misses the point — this is about friendly competition, learning, and sharpening your own forecasting. Weather apps aren't always right, and forecasting yourself builds a real feel for how weather behaves over time.

What are bonus points?

Bonus points are rare — awarded when a prediction is exactly correct. You can earn them on both the low and the high.

What is XP and how is it awarded?

See the XP page for how experience points are awarded.

What are bolts and how are they awarded?

Your bolt total appears on your scorecard, alongside your XP. Bolts are awarded for:

+2 for each prediction submitted
+10 when at least one bonus point is earned on a prediction
+1 at 10 XP · +2 at 25 · +5 at 50 · +10 at 75 · +15 at 100 · +20 at 250 · +35 at 500 · +50 at 1000 XP

When are scores calculated?

Grading runs each day at the configured hour (default 3 AM), in the local time of the current city, and usually finishes within a few minutes.

Where do the actual temperatures come from?

The site uses OpenWeatherMap, along with each city's coordinates, to record the day's actual high and low.

Can you add my city — or one outside the U.S.?

More cities will be added over time. Cities outside the U.S. depend on data and development availability.