Several PBS members from northern to southern coastal California and even
the south of France have described when bulbs emerge in the fall relative
to when the rain or irrigation begins. My garden is 300 miles south of
Mike's and 100 miles north of Lee's but unlike the others, no significant
rain has fallen yet this fall. (Rainfall amounts, in inches: June 0.10,
July 0.06, August 0.00, September 0.02, October thru 27th 0.00; 0.01 inch
is roughly 0.03 cm.) I will share my notes on which bulbs emerge without a
moisture trigger.

Then later in October more and more had shoots (just the white
cataphyll) and now even some have roots. This is without significant
precipitation.

Lately night temperatures have dipped below 50F / 10C and day temperatures
are mostly in the 70's reaching 80F/27C less often. Now the soil is around
60F/15C at 4 to 6 inches depth. This hints Narcissus tazetta primarily
responds to soil moisture but responds to cooling temperatures even without
any moisture, other than air humidity or dew. Another generalization I feel
confident making is that with moisture the roots emerge around the same
time as the shoots but in absence of moisture the shoot precedes the roots.