BTC ETH/BTC Trend Regime: 0.033
The ratio against its own 50- and 200-day averages. Above a rising 200-day line is the only stretch that honestly deserves the name ETH season.
The ETH/BTC ratio drawn with its 50-day and 200-day moving averages.
For example, ratio above both lines with the 200-day sloping up is a genuine ETH uptrend against bitcoin. Ratio below a falling 200-day is the long BTC-favouring regime that has held for most of the last three years.
The 50-day crossing the 200-day marks the handful of real turns; everything between them is noise.
Simple moving averages of the daily ratio over 50 and 200 days
Moving averages confirm a turn after it has happened - they never call one in advance. Both averages are computed over the full history and trimmed to your window afterwards, so a 90-day view still shows a true 200-day average.
Own compute - daily BTC closes (2010+) joined to daily ETH closes (2017+), no external API