1) Paint dries in tools a lot faster - plan on frequent cleanup.
2) I almost always use Floetrol to slow drying time.
3) I only paint surfaces that are in shade* and will stay in shade while the paint dries (more than to touch - at least a couple of hours).
4) In spite of all that, if temp will get much above 90 I use those hours for prep work.
*I just checked with an infrared thermometer. Air temp is 92. Wall of house continuously in shade is 92. Wall of house in full sun is 144.
Perhaps, but the paint I am currently using, and all other I recall reading the specific instructions (hmm... other than the one I just read, I wonder how many years it has been since I actually read a paint can?) say the air temperature should not be above 90. I have applied a LOT of paint when it was hotter than that but have learned to use the procedures I listed above.
It just occurred to me that as a resident of the Sacramento valley I make the unconscious assumption that hot = dry. Forcast humidity for this afternoon is 16%, heading down to 12% on Friday. Painting where hot = humid is outside my experience and may be a whole different world.
The result when painting the outside indeed depends largely on the weather conditions. My advice is first choose a good quality exterior paint. Woodyexpert has overviews about stucco paints you can check. Then, paint stucco when the temperature is between between 50-90F. It's better to let the paint dry over the night. However, the t shouldn't drop below 35F. Also, be sure there won't be any rains. You should also mind that the first coat can be applyed with a roller, but it's better to use a sprayer for the second one to avoid lap marks, which occur when paint dries too fast.