I was messing around on my creative single player world to get some data on temperature at different latitudes and altitudes and came up with this:

Latitude Average Temp. @ 160 Average Temp. @ 252
0 49.42 32.05
1000 46.26 28.9
2000 42.66 25.29
3000 38.92 21.55
4000 36.03 18.66
5000 31.73 14.36
6000 28.6 11.23
7000 25.52 8.16
8000 21.98 4.61
9000 18.35 0.98
10000 14.56 -2.81
11000 11.04 -6.33
12000 8.62 -8.75
13000 6.28 -11.09
14000 3.36 -14.01
15000 1.26 -16.11
16000 -0.64 -18.01
17000 -2.58 -19.95
18000 -4.91 -22.28
19000 -6.57 -23.94
20000 -7.93 -25.29
21000 -9.44 -26.81

I then cross checked this against the wiki to get possible animal spawning ranges:

Latitude Average Temp. @ 160 Average Temp. @ 252 Sheep Cows Pigs Chickens Horse Bear Deer Pheasant Wolf
0 49.42 32.05 No No No No No No No No No
1000 46.26 28.9 No No No No No No No No No
2000 42.66 25.29 No No Yes Yes No No No No No
3000 38.92 21.55 No No Yes Yes No No No No No
4000 36.03 18.66 No No Yes Yes No No No No No
5000 31.73 14.36 No No Yes Yes No No No No No
6000 28.6 11.23 No Yes Yes Yes Yes No No No No
7000 25.52 8.16 No Yes Yes Yes Yes No No No No
8000 21.98 4.61 Yes Yes Yes No Yes Yes No No Yes
9000 18.35 0.98 Yes Yes Yes No Yes Yes Yes Yes Yes
10000 14.56 -2.81 Yes Yes Yes No Yes Yes Yes Yes Yes
11000 11.04 -6.33 Yes Yes Yes No Yes Yes Yes Yes Yes
12000 8.62 -8.75 Yes Yes Yes No Yes Yes Yes Yes Yes
13000 6.28 -11.09 Yes Yes Yes No Yes Yes Yes Yes Yes
14000 3.36 -14.01 Yes Yes Yes No Yes Yes Yes Yes Yes
15000 1.26 -16.11 Yes Yes Yes No Yes Yes Yes Yes Yes
16000 -0.64 -18.01 Yes No Yes No No Yes Yes Yes Yes
17000 -2.58 -19.95 Yes No Yes No No Yes Yes Yes Yes
18000 -4.91 -22.28 Yes No Yes No No Yes Yes Yes Yes
19000 -6.57 -23.94 Yes No Yes No No Yes Yes Yes Yes
20000 -7.93 -25.29 Yes No Yes No No Yes Yes Yes Yes
21000 -9.44 -26.81 Yes No Yes No No Yes Yes Yes Yes

Note that different animals have additional spawning requirements that are biome and rainfall dependent. Check the wiki for details. I can make the following broad statements that may help you figure out how far north or south you should go for different animals and temperatures.

  1. No animals spawn within 2000 blocks of the equator.
  2. Chickens only spawn between 2000 and 7000 blocks of the equator.
  3. Sheep start spawning when you are more than 8000 blocks from the equator.
  4. Both cows and horses start spawning 6000 blocks from the equator but stop when you get more than 15000 blocks from the equator.
  5. If you liking hunting wild animals, look at least 9000 blocks from the equator.
  6. The temperature at y252 is about 17 degrees colder than the temperature at y160 no matter how far north or south you go.
  7. The temperature drops 34.86 degrees for the first 10000 blocks you walk from the equator but only 22.49 degrees after you walk an additional 10,000 blocks.
  8. The average biome temperature falls below zero once you are more than 16000 blocks from the equator.
  9. Pigs start spawning just 2000 blocks from the equator and can be found as far as 21000 blocks from the equator.