Wake County schools will release two hours early Wednesday in anticipation of inclement weather.

The school system made the announcement around 9 a.m. Some other Triangle school systems are also releasing early Wednesday, including Johnston County, Franklin County and Harnett County.

All after-school activities in Wake County schools are canceled Wednesday.

Wake schools had a two-hour delay Tuesday so buses could have extra time to warm up after several days of sitting idle in extremely cold temperatures over winter break.

Twenty-four of Wake’s 183 schools had issues with their heating systems Tuesday, spokeswoman Lisa Luten said. Green Hope High School in Cary released students early on Tuesday because of HVAC issues. Technicians repaired two broken boiler units at the school, where classroom temperatures were in the mid- to high-60s, Luten said.

Apex Middle School is closed Wednesday because the heat isn’t working properly.

The HVAC system at Ligon Middle School in Raleigh was not working properly Wednesday, but the school is open, Luten said.

Wake County is under a winter weather advisory through Wednesday night. Forecasts say that some areas could see up to 2 inches snow.

When inclement weather is expected, school systems often prefer to delay start times or release students early instead of canceling classes. That’s because schools can count an instructional day. Under state law, North Carolina schools must meet for 185 days or 1,025 instructional hours each school year.

If schools release early, “the day and the scheduled amount of instructional hours may count towards the retired minimum,” the law says.

Plus, an early release day brings out unbridled Twitter joy from Wake County students.