A sudden, short, and heavy rain that stops quickly
When to use
sudden rain, short duration rain, heavy rain, temporary rain
The nuance
Use 소나기 for intense rain that starts suddenly and lasts a very short time.
소나기 (so-na-gi, sonagi) · 장마 (jang-ma, jangma)
소나기 refers to a sudden, short, heavy rain, while 장마 means a prolonged rainy season lasting several days.

One lane per word — no nested boxes, just the gist.
A sudden, short, and heavy rain that stops quickly
When to use
sudden rain, short duration rain, heavy rain, temporary rain
The nuance
Use 소나기 for intense rain that starts suddenly and lasts a very short time.
Long-lasting rain over several days, usually in summer
When to use
long summer rain, multi-day rain, seasonal rain, continuous rain
The nuance
Use 장마 to describe rain lasting several days, especially during the summer rainy season.
소나기가 갑자기 내렸다가 금방 그쳤다.
so-na-gi-ga gap-ja-gi nae-ryeoss-da-ga geum-bang geu-chyeoss-da., so na gi ga gap ja gi nae ryeoss da ga geum bang geu chyeoss da.
This perfectly fits the definition of 소나기: sudden and short rain.
장마가 하루만 내렸다.
jang-ma-ga ha-ru-man nae-ryeoss-da., jang ma ga ha ru man nae ryeoss da.
장마 means rain lasting several days, so one day of rain is incorrect usage.
오늘 소나기가 계속 몇 시간 동안 내렸다.
o-neul so-na-gi-ga gye-sok myeoch si-gan dong-an nae-ryeoss-da., o neul so na gi ga gye sok myeoch si gan dong an nae ryeoss da.
소나기 is short and sudden; rain lasting several hours is not 소나기.
장마철에는 며칠 동안 비가 계속 내린다.
jang-ma-cheol-e-neun myeo-chil dong-an bi-ga gye-sok nae-rin-da., jang ma cheol e neun myeo chil dong an bi ga gye sok nae rin da.
Accurately describes 장마 as continuous rain over several days in the rainy season.
갑자기 소나기가 와서 우산을 펴야 했다.
gap-ja-gi so-na-gi-ga wa-seo u-san-eul pyeo-ya haess-da., gap ja gi so na gi ga wa seo u san eul pyeo ya haess da.
소나기 is appropriate for sudden rain requiring an umbrella quickly.
장마가 끝나고 다시 맑은 날씨가 되었다.
jang-ma-ga kkeut-na-go da-si mak-eun nal-ssi-ga doe-eoss-da., jang ma ga kkeut na go da si mak eun nal ssi ga doe eoss da.
Natural expression describing weather change after the 장마 season.
소나기가 며칠 동안 계속 내렸다.
so-na-gi-ga myeo-chil dong-an gye-sok nae-ryeoss-da., so na gi ga myeo chil dong an gye sok nae ryeoss da.
소나기 means short rain, so it cannot last several days.
장마는 갑자기 내렸다가 금방 그친다.
jang-ma-neun gap-ja-gi nae-ryeoss-da-ga geum-bang geu-chin-da., jang ma neun gap ja gi nae ryeoss da ga geum bang geu chin da.
장마 refers to multi-day rain, not sudden short showers.
Which word fits a sudden, brief rain?
What do you call rain lasting several days in summer?
Which word suits heavy rain lasting several hours?