Learn Swedish: Vi tog hänsyn till vädret när vi planerade. - We took the weather into consideration when we planned.

Yes, absolutely! Ta hänsyn till is a very common phrase that means both "to take into account" (like the weather here) and "to be considerate of". For example, du måste ta hänsyn till andra means "you must be considerate of others".

Could I use a single verb like "övervägde" instead of the phrase "tog hänsyn till" here?

Not quite. While överväga means "to consider", it usually refers to weighing a choice or an option, like deciding whether to do something (for example, vi överväger att flytta, meaning "we are considering moving"). Because the weather is an external factor you are adjusting your plans around, ta hänsyn till is the natural choice.

Why is the preposition "till" used here rather than "på" or "om"?

In Swedish, the noun hänsyn (consideration or regard) strictly pairs with the preposition till when specifying what you are considering. It is a fixed collocation, similar to how we say "pay attention to" rather than "pay attention on" in English.

Is the word "hänsyn" ever used with articles or in the plural?

It is an en-word (en hänsyn), but it is almost exclusively used in its uncountable, indefinite form. You will mostly encounter it in fixed expressions like ta hänsyn till or med hänsyn till (with regard to), so you rarely need to worry about its definite or plural endings.