Our first 70 degree day of the year occurred on Monday, which is a bit later than the average in recent years but nothing in the "oh my" department. What almost happened yesterday would have certainly qualified for "oh my" status.
Our high of 89 was a record high - heck, records were broken throughout the Delaware Valley. However, had we nudged out a 90 in the city we would have broken a record for the fastest occurrence of "first 90 after first 70" since people started tracking weather data in the city officially in the 1870's.
The record for fastest 90 after first 70 occurred back in April 13-17, 1896 (four days difference between 76 and 91) and on April 10-14, 1941 (71 to 91 in that timeframe). We would have a two day spread between first 70 and first 90 had we nudged an extra degree out of yesterday's warmth, which would have knocked those two records out.
The closest in recent times we have come to sniffing that record was 24 days, between April 9 and May 3, 2001.
Regarding Wilmington, where it did hit 90 yesterday, it would have been the fastest two day spread between first 70 and first 90 if not for their 70 back on January 30th (Philadelphia hit 68 that day).
Given today and tomorrow are going to be cooler with no 90 degree weather in sight, it looks like that 1941 and 1896 record is safe for another year.