If you're American, or come from a predominantly English speaking or Western country, you probably know that LA is known for its year long sunny weather. In Los Angeles, it probably rains a single digit amount of days on average per year (legit all day rain). It's always some combination of summer and fall, a weird hybrid of a never ending season that is only demarcated really by a variation of hours of sunlight. It's not quite hot enough to be tropical but it never gets below freezing.
It almost feels twilight zone-y, where the passage of time is thrown off because everything is just the same. It's hard to say things like, "remember that time in so and so season in that year", because you end up scratching your head and wondering when that actually was. It's funny when I saw people saying here how autumn was their favorite season, as we had two weeks of 90+ degree heat in the past month.
LA is technically a desert mediterranean climate, a climate really only found in the Mediterranean area and parts of Australia. Because of this, there's a bit of variation from area to area in daily temperature, the more inland you are the more extremes the temperature changes will be (Santa Monica's highs are almost always in the mid to high 60s, while downtown LA highs go from the high 60s in the winter to the mid 80s in the summer).
However, the weather doesn't really surprise you day after day. If today was a shorts and t-shirt day, tomorrow will likely be the same. There are definite pluses to this. You don't have to really think too hard about what you will need to brave the outdoors everyday, you just throw some stuff on and go. And going out in general is easier to do from a mood standpoint, there's very little from the elements that could stop you from feeling fine in leaving the great indoors.
There is something to note however: Since LA is a desert, the climate tends to variate more from day to night, due to specific heat of water being higher than dirt/concrete/land etc.. More inland, like the downtown area, there can be a 20-25 degree drop off from daytime to nighttime, so whenever you go out for the entire day, you'll probably want to pack a light jacket in your car for the night.
If it ever became practical for me to do so, I would live in LA during late spring to early fall and early winter to late spring and NYC on the opposing times. Of course there's a week or so I would enjoy the winter wonderland that takes place in the city, turning Christmas into, well, Christmas (commercial Christmas, I mean), but once I've had my fill, I don't think I would need it for three months. Overall, it's pretty nice having consistent weather day in, but sometimes you need a little spice.
From the info session that I attended about LA, they advertised the fact that there are times in the year where you can be snowboarding on a mountain, chilling in LA in regular weather, and soak in the pool in the heat all in the same day as those three different climates were within 100 miles of each other. If I were into that kind of thing, it'd be cool, but let's be honest, no one does that because of the traffic, which will bring me to my next entry.