BEIJING, June 24 (Xinhua) -- Beijing's observatory issued a blue alert on Monday for high temperatures over the next two days.

The temperature could rise to over 35 degrees Celsius in most parts of Beijing from Monday to Tuesday and could top 38 degrees Celsius in parts of the city on Monday.

The observatory advised residents to guard against the heat wave and said workers exposed to high temperatures should take protective measures.

An alert was issued during the past weekend, with the highest temperature reaching 38.8 degree Celsius on Sunday in the suburban district of Changping.

China has a four-tier color-coded weather warning system, with red representing the most severe, followed by orange, yellow and blue.