The weekly rush report will tell you. Seems like you'd have a 50-60% chance of winning lately, one of the easier lotteries to win. Of course it will usually be easier to win earlier in the week than on Friday and Saturday evenings. Rush Report
I have never won a Wed matinee..but won a Sat Matinee once. I also won Fri evening once and Sat evening 3 times. Go figure. It's really hit and miss. Once I won with about 200 people there..another time, there were 25 people there and they pulled 20 names and I didn't get it. (I play for friends at times...this is not all for me..LOL).
I do agree there is probably a 50-50 chance of winning and losing overall.
Personally I had the worst experience sitting in the balcony..for me, it's a show I appreciate more closer to the stage. My preference...I would do the lottery and then if I didn't win, I would go over to TKTS. It's there almost every day and their seats are not bad - and between 30-50% off depending on the day.
I won about a month ago for a Saturday matinee on a warm sunny day. 50/50 seems about right. The seat I got was something like seventh row way on the side: very partial view for anything that didn't take place upstage, but I certainly won't complain for the price. :)
That's a good tip in general. If it's been miserable, rainy and cold for days..and finally you have a drop dead beautiful day, it's always a good day for lotteries. A lot of people will go to the beach or park instead and don't want to be indoors..and may not choose to to go a show.