Climatology 101: 3rd warmest, 24th wettest July on record

July 2016 provided quite the Oreo cookie of weather. Sandwiched between periods of heavy Monsoon rainfall was the cream filling of a rare dry spell.

It’s a minor miracle that Tucson ended up with the 24th wettest July in recorded history. For 15 straight days, the Old Pueblo failed to register measurable rainfall. This marks the 3rd longest July dry streak dating back to 1895, a remarkable feat during the heart of the Monsoon. In the process, Tucson’s average temperature for the month came in at 90.3°. According to the weather records, that’s good for the 3rd warmest July.

July 2016 Report

So what bailed us out of a rainfall deficit? The start and end of July was wet, with the final 6 days of the month seeing measurable rainfall at Tucson International Airport. For the month, Tucson picked up 3.32″ of rainfall, which came in 1.07″ above normal.

It’s worth noting that between June 15th and July 31st, the official rain total at TIA was 4.71″. This is the 12th wettest total for these dates. Of the prior 11 6/15-7/31 periods, each one finished the Monsoon with above average rainfall.

Below is the complete July climate report, put together by the hard working men & women at National Weather Service Tucson:

A rather strange month July 2016 was. After scattered heavy rain resulted in flash flooding on the 1st, Mother Nature turned on a dry westerly flow aloft which brought a significant break to the monsoon that last over two weeks. Then a more favorable monsoon pattern took place after the 15th which lasted through much of the remainder of the month. Overall July 2016 goes into the record books as the 3rd hottest and 24th wettest on record.
As mentioned above the scattered heavy rain on the 1st resulted in flash flooding across parts of the city of Tucson where 2″-3″ was recorded. The high temperature on the first was a cool 86°, which is 16° below normal and ranks as the 3rd coolest July 1st day on record. An upper level trough passing by to the north of the state brought the needed dynamics to develop these strong and wet storms. The passage of this upper level trough left behind a drier westerly flow aloft which lasted across the area until mid-month. The airport didn’t record a drop of rain for 15 consecutive days, which is tied for the 3rd longest dry stretch during the month of July on record. The July record is 17 days from 1925. During this dry period, the airport recorded eight straight days where the high temperature was 105° or hotter.
The rain less streak ended on the 17th as the upper level flow started to become more favorable to bring the needed moisture for the daily chance of afternoon and evening showers and thunderstorms. In fact, the airport recorded rain on 11 of the last 15 days of the month with measurable rain being recorded on the last six days of the month. This six day stretch to end the month ranks tied as the 5th longest July measurable stretch on record. The record at the official recording spot in Tucson, dating back to 1895, is eight days in three Julys (1946, 1953 & 1955).
Temperature extremes for the month ranged from a high of 107° on the 21st to a low of 69° on the 1st & 31st. The monthly average temperature of 90.3° ranks not only as the 3rd hottest July on record it also ranks as the 3rd hottest calendar month on record. There were 25 triple digit highs of which 15 were 105° or hotter. This is the most number of 105° or hotter days in July since 19 were recorded in 2005.
Consider this. If you take away the cooler than normal start and end parts of the month (the blue bars in the graphics below), July 2016 would’ve been the hottest month on record.
July 2016 daily high temperature departure from normal July 2015 daily low temperature departure from normal
Click on image above for larger view
Rainfall across the metro area, using several sources like rainlog.org and the Pima County Regional Flood Control District gauges, varied widely from 0.50″ to 6.25″. The International airport, which is the official recording location for Tucson, recorded 3.32″ which ranks as the 24th wettest July on record.
July 2016 stats
Month
Normal
Departure
Average high temperature
102.5°
99.7°
+ 2.8°
Average low temperature
78.1°
74.4°
+ 3.7°
Average temperature
90.3°
87.0°
+ 3.3°
Days with highs 100° or greater
25
18
+ 7
Days with highs 105° or greater
15
8
+ 7
Rainfall
3.32″
2.25″
+ 1.07″

Summer 2016 (so far)
Two-thirds of Summer 2016 are in the record books and the average summer temperature of 89.4° ranks as the 2nd warmest to date (record is 89.8° from 1994). The average summer high temperature of 102.6° ranks as the 5th warmest to date (record is 105.3° from 1994). The average summer low temperature of 76.1° ranks as the WARMEST to date, besting the 75.6° from 2006. Rainfall across the metro area for summer 2016 so far has varied widely ranging from 1.50″ to 7.50″. Officially at the airport 4.91″ has been recorded which ranks as the 10th wettest summer to date on record.
For those tracking monsoon rainfall, 4.71″ has been recorded at the International airport, which ranks as the12th wettest June 15th to July 31st period on record. All of the 11 monsoon years that were wetter at the end of July than this year ended above normal.
Summer stats thru July
Summer
Normal
Departure
Average high temperature
102.6°
100.1°
+ 2.5°
Average low temperature
76.1°
72.0°
+ 4.1°
Average temperature
89.4°
86.0°
+ 3.4°
Days with highs 100° or greater
47
37
+ 10
Days with highs 105° or greater
24
17
+ 7
Days with highs 110° or greater
5
< 1
+ 5
Rainfall
4.91″
2.45″
+ 2.46″
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