RECORD BREAKING HEAT: Temperatures expected to be in the 110's across the region Monday KOMO News Staff Replay Video 5:29 p.m. Seattle reaches a new all-time record high temperature of 104 degrees. 4:43 p.m. NWS: Seattle (SeaTac) officially recorded a temperature of 103 degrees at 2:35 p.m Sunday. This ties the all-time record high since 1945. Caption: PM weather forecast 4:06 p.m. The National Weather Service has extended an Excessive Heat Warning through Tuesday for areas along and east of I-5. 2:36 p.m. Sea-Tac has reached 101 degrees. It's the first time Seattle's recorded two consecutive days above 100, the National Weather Service reports. This includes Seattle area records that date back to 1894.