The most efficient tilt for photovoltaic panels in Boston, Massachusetts at a latitude of 42.32°:
Your photovoltaic panels need to be angled facing south.
If you're mounting the photovoltaic panels at a stationary angle, such as on your roof, the most efficient angle is 35.3°.
If you're planning to change the angle of your photovoltaic panels twice per year, the most efficient angle is 18.4° in summer months and 56.2° in winter months.
If you're planning to change the angle of your photovoltaic panels each season, the most efficient angle is 14.6° in summer months and 61.7° in winter months, and 39.2° in autumn and spring months.