Friday will be another day of record heat and oppressive humidity in the Philadelphia region.
The previous record high for the month was 96 degrees, set in 1962.
The School District of Philadelphia says 57 schools will shift to virtual learning on Wednesday due to the extreme heat in the forecast.
Earlier on Monday, the president of the Philadelphia Federation of Teachers, Arthur Steinberg, voiced concerns about the district's handling of the heat.
The Philadelphia region could see record-breaking temperatures during the next three days as sunny, hot and humid conditions start the work week.
El Niño is expected to develop soon and could be the strongest on record, bringing with it more extreme weather. While the models indicate that this may be a strong event, the WMO cautioned that the models also have a harder time making accurate forecasts in the spring.