Heat waves in NYC: 3+ days in a row at 90°F or hotter. Mon, Jul 15, 1991: 90°F / 65°F Tue, Jul 16, 1991: 93°F / 67°F Wed, Jul 17, 1991: 96°F / 71°F Thu, Jul 18, 1991: 99°F / 75°F Fri, Jul 19, 1991: 96°F / 74°F, 0.01″ rain Sat, Jul 20, 1991: 100°F / 76°F Sun, Jul 21, 1991: 102°F / 74°F, 0.46″ rain Source: NOAA GHCN-Daily, Ny City Cntrl Park (USW00094728).