ようと思っているContinuing intention
The volitional form plus と思っている expresses an intention that the speaker has been holding or considering over time. It presents an ongoing plan rather than just a decision made at that moment.
An intention held over time
This pattern is useful when the intention already exists and is still in the speaker's mind. The plan may be firm or still under consideration; the important point is that it is not presented merely as a new decision made on the spot.
Continuing plans
A continuing thought or a settled intention?
ようと思っている presents the intention as something being maintained or considered. つもりだ states an intention more directly and often sounds more settled. They can describe similar real-world plans, but they do not focus on the plan in exactly the same way.
Intention versus schedule
ようと思っている describes what someone has in mind to do. 予定だ instead focuses on an arranged plan or schedule, so it is often better for fixed dates, bookings, and official plans.
More examples
健康のために、これからは毎日歩こうと思っている。
For my health, I intend to walk every day from now on.
Analyze次の休みに、この小説を最後まで読もうと思っています。
I am planning to finish reading this novel during my next break.
Analyze来学期は日本史の授業を取ろうと思っています。
I am thinking of taking a Japanese history class next term.
Analyze週末に台所をきれいにしようと思っている。
I am planning to clean the kitchen this weekend.
Analyze春になったら、京都へ桜を見に行こうと思っています。
When spring comes, I am thinking of going to Kyoto to see the cherry blossoms.
Analyzeしばらく車は買わないでおこうと思っています。
I intend not to buy a car for a while.
Analyze