BUENOS AIRES (Reuters) -Argentina's monthly inflation rate stood at 4.2% in August, official data published on Wednesday showed, rising from last month and surpassing analysts' forecasts, while Argentines tighten their wallets to deal with spiraling costs.

Inflation in the 12 months through August reached 236.7%, still the highest level recorded in the world, and also above a Reuters poll forecast of 235.8%.

Analysts had hoped for a slight monthly slowdown to 3.9%, which would signal progress for the government of libertarian President Javier Milei, which has been focused on taming runaway prices.

Statistics agency INDEC said the monthly price rises were driven by living costs and utilities, education and transport. The country's monthly inflation rate has hovered around the 4% mark since May.

With costs soaring, poverty rates this year hit their highest level in at least 20 years, according to a recent study.

"I swear I don't know how to make ends meet," said 63-year-old Liliana Martins, lamenting that, even as she tries to save, it is never enough.

A kilogram (2.2 pounds) of potatoes now costs 1,274 pesos ($1.33), according to INDEC, up nearly 40% from just a month ago, while prices for meat, dairy and soaps have also gone up.

Agustina Celeste Brito, a 24-year-old teacher, said she was pooling her salary with her parents' to get by, while 27-year-old Victoria Godoy said rising household costs are too much for her to cover.

"I pay all the utilities, and every month it goes up and the salary I make is not enough," Godoy said.

($1 = 957.5000 Argentine pesos)