The warmest January inauguration on record belongs to Ronald Reagan, who was sworn in to temperatures in the mid-50s to start his first term in 1981. There is a chance temperatures will be this warm for Trump, possibly warmer.
The wild card is whether rain falls, which models suggest is a possibility and would limit how high temperatures rise.
Weather models are unanimous that much of the eastern two-thirds of the country will experience a weather pattern conducive to milder-than-normal weather late next week.
The jet stream will lift north into Canada allowing mild air flow from the south and southwest during the period. Some record high temperatures could be set in this pattern.
The National Weather Service’s six- to 10-day temperatures outlook shows high probabilities of above normal temperature, and its accompanying discussion says its confidence in the outlook is “above average, 4 out of 5, due to good agreement among the model solutions and various forecast tools.”
Predicting the exact high temperature seven days in advance is very difficult, as minor changes in weather systems can lead to big changes in the forecast temperature.
Based on available information, but subject to change, we think a high temperature in the upper 50s is most likely — with a noon, swearing-in temperature in the low-to-mid 50s — conditions comparable to Reagan’s first inauguration.
But it could certainly be warmer or cooler than this. Here are some odds for different high temperature outcomes:
- 40 degrees or colder: 5 percent
- 41-50 degrees: 25 percent
- 51-60 degrees: 40 percent
- 61-70 degrees: 25 percent
- Above 70 degrees: 5 percent
In other words, we think there’s a 70 percent chance the high will be above 50, and 25 percent chance of highs above 60. Those are great odds for mild weather for Jan. 20!
Whether it’s cloudy and rainy or dry and sunny will make the difference between a day closer to 50 degrees vs. a day well into the 60s.
Some runs of the American (Global Forecast System) model suggest an upper-level disturbance could swing through the region Jan. 20 producing overcast skies and rain, which hold high temperatures in the 50s.
But the European model forecasts this disturbance to be weak and exiting the region early in the day. It favors mostly dry weather and a high temperature of a rather remarkable 69 degrees.
If the European model is right, which is a stretch for a forecast so far into the future, the high temperature would flirt with the record for Jan. 20 of 70 degrees from 1951 (a non-inauguration year).
The bottom line is that all indicators point to mild weather, but how mild will depend on whether it’s rainy. We’d put the odds of rain at 30 percent. It will take a few more days to have more confidence in this aspect of the forecast.
Of course, there is plenty of interest in the weather for Jan. 21 in addition to Jan. 20 given the Women’s March on Washington. It could be just as mild that day and the odds of rain may be slightly lower.