Not only will summer's unofficial swan song feature spectacular weather, but we're also getting gifted with changes on only 12 subway lines this weekend. A blessing indeed! Who needs Summer Fridays when you can make it from Park Slope to the Upper West Side in under five transfers? NOT ME, NOT ME, MY FRIEND.

Here's what's on tap this weekend:

1 trains will not run in either direction between 14 St and South Ferry, starting at 11:30 p.m. Friday and ending at 5 a.m. Tuesday.

2 trains will not run in either direction between E 180 St and 149 St-Grand Concourse from 11:30 p.m. Friday to 5 a.m. Monday. Trains will run local between Chambers St and 34 St-Penn Station in both directions, starting at 11:30 p.m. Friday and ending at 5 a.m. Tuesday. Trains will skip Church Av from 1 a.m. to 4 a.m. on Monday.

3 trains will run local between Chambers St and 34 St-Penn Station on both tracks starting at 6:30 a.m. and ending at midnight Saturday to Monday.

Crown Hts-Utica Av bound 4 trains will run express from 14 St-Union Sq to Brooklyn Bridge-City Hall from 11:45 p.m. Friday to 7:30 a.m. Sunday, and again from 11:45 p.m. Sunday to 5 a.m. Monday. All 4 trains will run local in Brooklyn from 11 a.m. to 7 p.m. on Monday; they will skip Eastern Pkwy-Brooklyn Museum during that time.

5 trains will not run at all between E 180 St and Bowling Green, starting at 6:30 a.m. and ending at 11:30 p.m. on Saturday, and then again from 8 a.m. to 11:30 p.m. on Sunday.

Brooklyn Bridge-City Hall bound 6 trains will run express from 14 St-Union Sq to Brooklyn Bridge-City Hall, starting at 11:45 p.m. Friday and ending at 5 a.m. Monday.

Downtown A trains will make express stops from 59 St-Columbus Circle to Canal St, with that change in effect from 11:45 a.m. Friday to 6:30 a.m. Monday, and again from 11:45 p.m. Monday to 5 a.m. Tuesday. During that time, Inwood-207 St bound A trains will run express from 125 St to 168 St.

Downtown C trains will run express from 59 St-Columbus Circle to Canal St from 6:30 a.m. to 11 p.m. Saturday, Sunday and Monday. During that period, 168 St-bound C trains run express from 125 St to 168 St.

All E trains will make local stops from Queens Plaza to Forest Hills-71 Av, with that change in effect from 12:01 a.m. Saturday to 5 a.m. Tuesday.

Jamaica-179 St bound F trains will run express from Neptune Av to Smith-9 Sts from 11:45 p.m. Friday to 5 a.m. Tuesday. During that period, Coney Island-Stillwell Av bound F trains will reroute along the E line from Roosevelt Av. All F trains will run local in Queens from 12:01 a.m. Saturday to 5 a.m. Monday.

J trains will run every 20 minutes from 12:01 a.m. Saturday to 5 a.m. Monday. Some Jamaica Center-Parsons/Archer-bound J trains will terminate at 111 St.

Manhattan-bound Q will trains run express from Kings Hwy to Prospect Park, with that change in effect from 11:15 p.m. Friday to 5 a.m. Monday.