Summary of Bitcoin's performance in May in recent years:

May 2021: -35.31% (Significant decline, mainly due to regulatory crackdowns such as China's mining crackdown, quick pullback from the high point).
May 2022: approximately -15% to -20% (Bear market continues, prices dip to lower levels).
May 2023: slight positive return or flat (Bull market recovery, mild fluctuations).
May 2024: sideways or slight decline (Post-halving, price adjusts in the $60k-$70k range, then continues upward).
May 2025: positive return (Once rose from about $94k to hit a high of $111k, overall strong in May, but with later pullback).
For earlier years (2017-2020): May 2017: strong rally (Bull market, rapid surge from over $1k).
May 2018: decline (Bear market).
May 2019-2020: mixed, some years positive returns.
Overall statistical trend (long-term backtest, approximately 2011-2025/2026): The average return in May ranks as mid-lower among Bitcoin months (not the worst month; sometimes September-October are weaker).
The summer half-year (May-October) historically yields significantly lower cumulative returns than the winter half-year.
Proportion of positive return months: about 50-60% in May (high volatility, no overwhelming advantage).
Most strong months are commonly: October-November, January-March, December; weaker months include: May-September, June-August summer months.