I'm no Baja expert, only having been down there a few times. The whale watching peaks in February I think, there were a few to be seen at the end of March during our Cabo San Lucas honeymoon a few months ago.
Word is, from the locals, July the hot a humid, August gets tropical storms, sometimes flooding in the washes, most of the tourists don't bother coming down during that time.
If it were me, I might explore the California and Oregon coasts, San Juan Islands of Washington instead, and hold off until November or December to head south of the border.
1995 E350 7.3 Diesel, 4x4 high roof camper, UJOR 4" lift