Boise’s January warm trend peaks with record high

The high temperature in Boise topped out at 58 degrees Thursday at 1:58 p.m. — a record high for Jan. 18, according to the National Weather Service.

The previous record high was 57. The normal temperature for Jan. 18 is 38.

The first half of January has been warmer than normal — and much warmer than last year at this time — but it’s not at all unusual for Boise to have 50-degree days in January, Weather Service data show.

In fact, a look at 30 years of climatological data shows that Boise averages two 50-degree days in January, according to Weather Service meteorologist Dave Groenert. That data is for the period 1987 to 2016.

Thursday is our fifth 50-degree or warmer day so far this January. A cold front is coming through Thursday night to cool things down.

A ridge over the Northwest created record high temperatures in some places. The high in Seattle Monday was 64, eclipsing the previous record high of 58 for Jan. 15, the Weather Service said. It tied the record for the highest recorded temperature for January in Seattle.

The cold front headed to Boise on Thursday will bring rain, with the possibility of snow on Friday. We’ll see less than an inch of accumulation in Boise, while Bogus Basin Mountain Recreation Area may get another 2 to 4 inches of powder, meteorologist Stephen Parker said Thursday.

This past week’s spring-like weather has been in a stark contrast to last January.

The highest temperature recorded during January 2017 was 45, and there were 21 days when the high temperature never rose above 32.

Our coldest temperature so far this year is 18 (Jan. 2). There were five days below zero last January, including -11 on Jan. 6.

Let’s take a look at numbers from a few other recent Januaries:

▪  2016. Warmer than normal.

The highest temperature was 50, and the lowest was 4. There were just two days when temperatures didn’t rise above 32.

Average monthly temperature: 33.6

▪  2015. Slightly warmer than normal.

The highest temperature was 50, and the lowest temperature was 6. There were five days when highs didn’t exceed 32.

Average monthly temperature: 31.7

▪  2014. Slightly colder than normal.

The highest temperature was 54, and the lowest was 15. There were 11 days when highs didn’t rise above 32.

Average monthly temperature: 30.5

▪  2013. Significantly colder than normal.

The highest temperature was 47, and the lowest was -3. There were 21 days when the high temperature was 32 or colder.

Average monthly temperature: 19.6

This story was originally published January 16, 2018 at 6:43 AM with the headline "Boise’s January warm trend peaks with record high."