I also picked February. While the weather is never really bad in Arizona, February is when I start to get sick of all the snowbirds here. Plus, after the Super Bowl, there is a let down for sports fans.
March is probably my favorite month. Spring Training and the start of the hot and dry weather!
January, solely because of the weather. My favorite is May.
Perhaps cliche because it’s true. December is the beginning of winter, and hence the end of happiness. The beginning of year-end madness at work (do I finally get to sleep again, now that it’s over?), holiday hell, holiday travel hell, radio stations not playing anything but Xmas music for a whole bloody month! When I finally figure out how to build my time machine, I’m not even going to visit the past or the distant future; I will use it exclusively for skipping December of every single year.
July.
I would’ve said August, because August is usually worse weather-wise (I despise summer), but my birthday is in August, and it’s hard to hate a month when you get loot.
July, August and September all suck - I hate summer. Too goddamn hot, and I live in the PNW. August is generally the worst, so it got my vote.
olives, I love March here in Virginia. Because March is the month that really shows the difference between Virginia and the frozen North where I grew up. In the North, March was always an endless purgatory of cold. Winter seemed to linger long after by any sense of decency it should have been over with. But in Virginia, March brings the beautiful spring weather. A touch muddy, but I feel so alive again as soon as it gets springlike. My favorite Virginian day every year is the first warm day in March. I revel in the warmth as the bitter endless cold of northern Ohio fades away in memory like a bad dream. In the middle of winter, it gets just as cold here as up north. But the real difference comes in March, when winter departs early, like it’s supposed to.
I voted for February, based on how it is in the US - usually the worst weather in terms of cold, and with short dreary days.
Here in Panama, my least favorite months are October and November, the depths of the rainy season when it sometimes rains all day. November is somewhat redeemed by Thanksgiving (when I go to the US), so October is probably the worst.
February here is one of the best months - it’s the middle of the dry season, the trade winds are blowing, and all the trees are in flower.
I’m with the hot-weather haters, and picked the endless month of August.
I’m going to be a rogue and say June. I hate June. When I get rich, I plan on spending every June away from here, every year. It’s usually very hot, and very, very dry. The monsoon hasn’t begun yet, and every day is sunny, bright, hot, and dry. It’s excrutiating, and even July’s humidity and frequent afternoon storms are welcome after the hell that is June.
I should add that August through October and even November here in So. Cal. tend towards hot, dry, windy and aflame, so I really don’t like any of them.
sorry if it’s a cliche, but I really dislike December. Holiday stress, even if I can avoid it, permeates the month.
If my birthday wasn’t in February, I might have chosen that. It’s probably the coldest month of the year, but it’s short. By the time March rolls around, all you want is spring and fresh air back, but no, March just continues to dump wet snow, cold rain, bitter temperatures, and horribly gray weather on your face. April is a strong contender too, but at least spring is starting to pry the top off of winter. I do find Easter incredibly annoying as a holiday though.
Much appologies Olives, but March blows! 
I picked February, but in retrospect, it’s also when spring break starts, and this year I am going to the Philippines for my break (it’s an Educational Experience, though, so it won’t about lying on beaches or anything like that). Last year I went to Colombia. So maybe February is okay.
Even though I hate the snow, I like cooler weather. I detest the steamy hot of summer. July or August. I picked August.
July. Around here it’s hot and humid and the saylights lasts so long it’s hard to sleep.
I hate the heat. January however is lovely (I live in Tucson). 68 degrees and sunny today.
Another vote for August. Too hot, no holidays. Blah.
I voted for January, but according to T. S. Eliot, April is the cruellest month.
February. It’s hideous in Sydney: hot and humid.
Definitely January. Holidays are over, all the family birthdays are over and done with until next June, all the money gone and very little work to be found in construction. Plus it’s cold and we’re always sniffling and snorting. It’s too cold to send the little one out to play, and it’s dangerous when we get ice but I still have to get out in it every day to drive my daughter to work. Blah!
March. At that point winter has long since worn out it’s welcome and nice weather is a ways off yet.
A case could be made for April because it will tease with an occasional nice day and then slap you with a miserable one.