The only thing the weather may trigger on me is a headache...usually a sinus headache.
Indoor or outdoor lighting issues

Bright sunlight sometimes triggers migraines...which theoretically may trigger some som symptoms.  Still trying to figure that one out. 

You mean, like at the disco?  lol 
Night driving

I have not been able to see well to drive at night for quite a few years...usually ok in town, definitely have trouble in the country or on the highway or in unfamiliar territory...does it trigger the som?  I don't think so.
Seasonal changes

Well, believe it or not...I seem to have more trouble in the summer/early fall.  Although I don't know why. 
Sinus and/or upper respiratory conditions

I do have sinus and allergy problems...again, does it trigger my som?  I don't know if it triggers it, but occasionally, they do occur simulaneously.
Colds, flu

No correlation there.
Insufficient sleep

Definitely a factor...if I get less than 6 hours of sleep, I can feel the eye quivering.
Emotional conditions or situations

Absolutely...I had a big flare up after my dad died. 
Work issues, like computers or other focused tasks/jobs

Well, working in the pharmacy, I had plenty trouble gazing downward...however, I believe some of that had to do with his weird patterned carpeting on the floor.  Yes, I think that was a trigger. 
Chemical agents, i.e. cleaning products

Doesn't appear to be any connection for me....of course, if I actually used cleaning products...(just kidding!)
Stress

Oh, boy and how. 
Any other environmental or situational issues

I too have a certain amount of trouble if people stand to my left or stand too close to me....As I said earlier, sometimes glancing downward triggers, or if my neck is stiff that will trigger it as well.