RUDO Weather Challenge · El Niño Challenge Season
Let tomorrow's weather test your judgment.
Forecast the daily high at Boston Logan, keep a receipt, then check it against the NWS climate report. Learn weather with mathematics and AI, and bring what you find back home.
1 station · 1 variable · 1 scoring rule
Current round
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Three steps
Make a forecast, keep the receipt, see what happened.
Choose your family entry
A parent or guardian creates a family in under a minute. No email, names or birthdays.
Forecast and get a receipt
Enter tomorrow's high in °C with one decimal and say whether you used AI. Your receipt proves the forecast was not changed.
Reveal and review
When the NWS report arrives, see your exact error next to simple reference lines, then try again.
Learning paths
Short lessons that make the next forecast better.
Latest verified day
How the yardsticks did.
Reference lines are simple methods we score the same way as everyone else. They are yardsticks, not competitors.
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One ruler, three boundaries
The same rules for everyone, in the open.
One station
Everyone, everywhere, forecasts the daily high at Boston Logan. Where you live does not change your score.
One deadline: 18:00 EST the day before
That is 23:00 UTC. The server clock decides, and a forecast received exactly at the cutoff is late.
One truth source: the NWS daily climate report
The first complete report for Boston after the day ends. Corrections within 7 days are applied; after that the result is final.
Season calendar
El Niño Challenge Season 2026–27
Core rounds are S-01 (2026-11-21), S-02 (11-23) and S-03 (11-25), then every Saturday and Wednesday target day through 2027-02-28. Every other day is an open practice round.
Season 1 has no leaderboard and no percentiles. Each participant sees their own forecasts, errors, reference lines and coverage.