My theory goes something like this. Cancer rules the moon and having the sun in Cancer or even an Ascendant in Cancer in the Natal chart gives us more access to the moon's energies. For most signs, the Solar Return moon is just another energy in the transit chart, but for the Cancer, ruled by the moon, the sign of the Solar Return Moon matters a great deal. Not only will Cancers experience the themes of that moon, but expect the personality to alter a bit or a lot depending on the sign. Though I will say that the comfort level decreases when the Solar Return Moon falls in a Fire or Air Sign unless the Cancer Sun Native has several planets in Fire or Air signs in their Natal chart. Does this make sense?
So if you have a Cancer Sun (or Ascendant), take a look at your Solar Return chart for the 2015-2016 SR year. Now, this will be different for those of you with the Cancer Ascendant and I only mention the Ascendant because it represents our self-identity. Your Solar Return chart won't take place in June and July when the Cancer Sun rules, but at whatever time your Sun Sign rules. But those of you with a Cancer Sun look back to your last birthday chart (which is the Solar Return chart) and find the moon and it's sign. Look at the house it falls in and the themes of that house, using my cheat sheet and then the sign of the Solar Return moon.
Then for the next 12 months or so, see what areas of your life have changed. How has your attitude or personality changed during that time? For Cancer Sun we are approaching 6 months into this journey. So how has your Solar Return moon shaped your life thus far? Are you wanting to travel or spend more time at home? Are you feeling more adventurous or less? Are you changing your eating habits, finding that you're picky, or wanting to break up with your partner? Your experiences will differ depending on the Zodiac Sign your Solar Moon falls for the year. Then track the Solar Moon signs for the next several years because it changes every year.
Now, I'm wondering if it works the same way with the Solar Return Mercury for Virgo and Gemini, changing their communication style from year to year (even if with Mercury you only get a choice of three signs adjacent to your Solar Return or Natal chart Sun). But for now, let's stick to Cancerians and the Solar Return Moon. I enjoy astrological experiments and if you are Cancerian please leave your observations in the comments below.