Good point. Relevant article: http://lampx.tugraz.at/~hadley/uncomputable_numbers.html

"almost every number is uncomputable"

"This means that predicting the weather arbitrarily far into the future is impossible without knowing the current conditions (temperature, air pressure, humidity, wind speed, etc.) to arbitrary precision. Since the quantities that describe the weather are real numbers, they are uncomputable. No finite computer program can calculate the weather arbitrarily far into the future."