A chilly first half of January outmatched a much warmer second half in Tucson, leading to temperatures that averaged well below normal for the entire month.

The first 16 days of the month averaged 8.6 degrees below normal. It was the fourth-coldest first half of January since Tucson weather records started being kept in 1895.

Helping drive those temperatures down was a period from Jan. 11 to 15 with some of the coldest temperatures the Tucson area has experienced since 1971, the weather service said.

From early on the morning of Jan. 11 through 15, the temperature never reached 50, the longest such period since January 1971. The mornings of the 14th and 15th brought record lows of 21 and 17 degrees, respectively.

Starting on the 17th, temperatures shot up, hit a record high of 81 on the 22nd and tied a record the next day with a high of 80. The period Jan. 17 to 31 was the 10th-warmest second half of January on record.

The entire month was the 36th-coldest on record, with an average monthly temperature of 49.8, 2.8 degrees below normal. On 12 days, temperatures hit 32 or lower - the most such days for any January since 1964.

Rainfall was slightly below normal - 0.81 of an inch compared to a normal of 0.94 of an inch.

Contact reporter Tony Davis at tdavis@azstarnet.com or 806-7746.