obliquity

Here is a scan from The Planetary Scientist's Companion, by Lodders and Fegley, published by Oxford University Press, 1998, Table 2.5 (page 91). The fifth column (of data) down is Obliquity to Orbit (measured in degrees). You can see that four of the planets, including Earth, have angles of obliquity between 23.45 degrees and 29.56 degrees. These are The Four "Seasonal" Planets.