Alright, so I'm intending to make a 4th Gen link battle UU Sunny Day team, but since this is my first team I'm ever assembling, I wanted some advice before I go and make the team. I made the team using the Teambuilder on Pokemon Online, and I appreciate any and all comments.

Ambipom @ Focus Sash ** Beetle (Here Comes the Sun)
Trait: Jolly
EVs: 4 HP/252 Attack/252 Speed
Moveset:
Sunny Day
U-Turn
Taunt
Sand-Attack

What I wanted for Ambipom was to be the lead, first setting up Sunny Day, then switching out with U-Turn to bring in one of the sweepers who rely on the sun. Other than that, he's a pure Annoyer.

Arcanine @ Life Orb ** Len (Steal My Sunshine)
Trait: Lonely
EVs: 252 Attack/4 Spe. Attack/252 Speed
Moveset:
Solar Beam
Morning Sun
ExtremeSpeed
Flare Blitz

With Arcanine, he's pretty much my Physical Sweeper, with the exception of Solar Beam, which I can use if the sun is out. Morning Sun allows me to recover most of the HP lost due to Life Orb, especially when the sun is out, and ExtremeSpeed will allow me to get a few hits on the few that are faster than Arcanine.

Moltres @ Life Orb ** Hi-Tel (Sun God)
Trait: Timid
EVs: 4 Defense/252 Spe. Attack/252 Speed
Moveset:
Sunny Day
Solar Beam
Morning Sun
Fire Blast

Moltres is the Special Sweeper of the group, with the added bonus of being able to bring back the sun should he need to. I figure he'll probably only come in late in the game, which is why I gave him Sunny Day. Morning Sun again is to try and counter the Life Orb, while Solar Beam is set to go off during the sun, and Fire Blast if I can't achieve that.

Claydol @ Heat Rock ** Diffie (Third Rock From the Sun)
Trait: Impish
EVs: 252 HP/252 Spe. Defense/4 Speed
Moveset:
Sunny Day
Earthquake
Reflect
Stealth Rock

This is an alternate lead I read about while researching Sunny Day teams, and it seemed interesting, so I wanted to give it a shot. However, I didn't really like the Explosion attack too much, so I decided I want to try Earthquake, but I'm still sort of iffy about that one. Basically, he sets up the sun, throws out some stealth rocks, and gives the team some added defenses with Reflect. If he needs to, he throws out an Earthquake or two, though I don't think I'm gonna need to, I'll probably just switch out or something.

Venusaur @ Life Orb ** Crow (Soak Up the Sun)
Trait: Timid
EVs: 4 HP/252 Spe. Attack/252 Speed
Moveset:
Leaf Storm
Synthesis
Sludge Bomb
Solar Beam

Venusaur is one of my favourite Pokemon, and the whole reason I made this team in the first place. He's another Special Sweeper, which I'm not sure if that's bad to have 2 Special Sweepers, but I thought it was a good idea. Solar Beam is obviously for under the sun, and Leaf Storm will counter all those Rock types who threaten my Arcanine and Moltres. Synthesis will help counter Life Orb, and Sludge Bomb is for just in case.

Tangrowth @ Leftovers ** Hank W (All for the Love of Sunshine)
Trait: Rash
EVs: 32 Attack/252 Spe. Attack/224 Speed
Moveset:
Ancient Power
Power Whip
Solar Beam
Sleep Powder

With Tangrowth, he's my attempt at a Mixed Sweeper. His Ancient Power should deal with any Fire types that come in, while Solar Beam is ready for sunshine spamming. Sleep Powder should buy me at least a turn to hit them with something, or at least switch out should I find myself at a disadvantage.

Well, there's my Sunny Day team. I'm sure it's not great, but it's my first team, and that's why I'm posting here, so I can figure out the weaknesses and try to fix them. Any comments will be much appreciated!