Why do scientist have to use weather insturments?

Answer 1

This is a rediculous quesiton. Would you want people to guess?

Answer 2

Weather forecasting cannot be predict by approx calculation, the time when scientist are trying to get most accurate instruments and results so the havoc happening every year can be minimized..millions of people die every year because they were not warned before the havoc had passed, a country which have a effective forecasting methodology is automatically have criteria of a most developed nation...i don't think this is possible without science & technology (instruments)...you question is just like why we use Pen to write?...do you answer this ..if than you have your question answers too.

Answer 3

Because they don't all have a bum knee to do it for them.

Seriously, though - it's because some of the factors used to evaluate the weather measure things that humans can't (such as air pressure) or can't measure accurately (such as temperature).

Answer 4

Because if they didn't use instruments they would have to guess by wetting a finger and holding it up in wind.
If you had something else in mind, clarify your question.