By Rod Hill on 2021-06-23

The Excessive Heat Warning issued by the National Weather Service (NWS) for Saturday
through Monday will likely produce the season's first triple digit heat.

The period of 90 degree or higher temperatures starting Friday and possibly continuing through
Monday July 5th is on track to be historic for several reasons:

1) The all-time hottest June temperature at PDX of 102° will likely be broken.

2) Portland's all-time hottest temperature on record for any time of year may be tied
or broken. The record of 107 degrees has been reached three times over the years. Sunday's high temperature has a chance to reach or surpass the record last reached in August of 1981.

3) The length of the expected heat wave may produce a total of 10 June days reaching 90 degrees or hotter. The current record total for 90° days in June is 9 days back in 2015. The streak into July may reach a total of 11 consecutive days, which would also break a record. 

4) Many daily temperature records are likely to fall, including daytime highs and records
for warm overnight lows. The current forecast shows low temperatures in the 70s Sunday and Monday mornings and both would set records. In fact, the all-time warmest low temperature at PDX in June is 71 degrees. I expect the record to fall.

It is important to note that an unprecedented June heat wave does not guarantee a record hot summer. Meaning the upcoming hot spell could be the worst this summer season offers up. 

Rod Hill