Consumer prices rose 0.9 percent in June, according to data released Tuesday by the Labor Department, heating up from the previous month.

The consumer price index (CPI), a closely watched gauge of inflation, increased to an annualized rate of 5.4 percent last month amid a summer rush of economic activity. Economists expected the CPI to rise by roughly 0.5 in June, according to consensus estimates, after an increase of 0.6 percent in May.

June’s monthly increase in the CPI was the largest recorded since a 1-percent increase in June 2008. The annualized rise in inflation is the highest since another 5.4-percent increase in August 2008.