Kaisei
- Gender
- Boy
- Say it
- ky-SAY
- Origin
- Japanese
- US rank, 2025
- #10,690 for boys
Kaisei is a boys' name of Japanese origin. In 2025 it ranked 10,690th for boys in the US (6 babies).
What does Kaisei mean?
Japanese: Japanese; meaning depends on the kanji used
One common writing, 快晴, is the Japanese word for clear, cloudless weather.
Is Kaisei a girl's or a boy's name?
Kaisei is a boys' name. In 2025, it was given to 6 boys in the US. Too few girls were given it to be listed.
How popular is Kaisei in the US?
- Rank in 2025
- #10,690among boys
- Babies in 2025
- 6about 1 in 280,000 boys
- Five-year trend
- Too rare to calltoo few babies to tell
- Same name in a class
- under 1%chance among 15 boys
In 2025, 6 boys in the US were named Kaisei, making it the 10,690th most popular name for boys. Its busiest year was 2007, with 10 boys. It first appears in the records in 2005.
Half of all the boys named Kaisei in the US since 1880 were born between 2010 and 2019, the years shaded on the chart below.
Kaisei in the US, year by year
| Year | Boys | Rank |
|---|---|---|
| 2025 | 6 | #10,690 |
| 2024 | 9 | #8,307 |
| 2023 | 6 | #10,815 |
| 2022 | 7 | #9,815 |
| 2021 | 6 | #10,794 |
| 2020 | 0 | – |
| 2019 | 9 | #8,209 |
| 2018 | 5 | #12,150 |
| 2017 | 9 | #8,136 |
| 2016 | 6 | #10,739 |
| 2015 | 7 | #9,562 |
| 2014 | 9 | #8,124 |
| 2013 | 9 | #8,113 |
| 2012 | 7 | #9,703 |
| 2011 | 0 | – |
| 2010 | 9 | #8,133 |
| 2009 | 7 | #9,859 |
| 2008 | 5 | #12,546 |
| 2007 | 10 | #7,586 |
| 2006 | 6 | #10,655 |
| 2005 | 5 | #11,464 |
Names like Kaisei
Names given in the same years and the same naming tradition, with a similar sound.
Kairo Kaizen Kenzo Kasai Tru Sakai Koa Kenai Akari Loki Kota Makai
Names related to Kaisei
More Japanese names
Kobe Raiden Ren Ronin Kyomi Akira Yuna Emi Kiyomi Kairi Miya Kenji Reo Jiraiya Aizen Sora
Sources
Figures from Popular Baby Names (US Social Security Administration). Nameling last updated them on 20 October 2026. How the figures are worked out, and the data to download.
To cite this page: Nameling, “Kaisei: name meaning, origin and popularity”, https://www.nameling.co.uk/names/kaisei, updated 20 October 2026.