RodneyS

October 2023 at DCA came in above the 1991-2020 normal, at 63.1 degrees, which was higher than October 2012 (61.0), but lower than October 2017 (64.9). So, the first 10 months of 2023 gained on 2012, but fell behind 2017, with an average temperature of 64.0 degrees versus 64.7 for the first 10 months of 2012 and 64.1 for the first 10 months of 2017. 2023 could still be the warmest year ever in DC, if it were to average about 50 degrees during November and December. Under that circumstance, the final two months of 2023 would be the third warmest ever, behind only 2015 (52.5) and 2001 (50.2).

DCA_NYC_BOS__ ORD_ATL_IAH__ DEN_ PHX_ SEA -1.1 0.1 0.1 -0.3 -1.4 0.7 -0.7 0.1 0.9

September 2023 at DCA came in above the 1991-2020 normal, at 73.4 degrees, which was higher than both September 2012 (72.2) and September 2017 (72.6). So, the first nine months of 2023 gained on both 2012 and 2017, with an average temperature of 64.1 degrees versus 65.1 for the first nine months of 2012 and 64.0 for the first nine months of 2017. Thus, while 2023 is averaging about a degree cooler per day than 2012 did during its first nine months, 2023 is averaging a tad warmer than 2017 did during its first nine months.

DCA _ NYC _ BOS __ ORD _ ATL _ IAH ___ DEN _ PHX _ SEA -0.3 0.5 1.0 1.7 -0.8 2.5 1.0 -0.6 0.6

Awesome job for many years, Roger -- many thanks.

A remarkable 4-day run at Dulles. In the 60 Septembers prior to 2023 at IAD, only three 99-degree readings had been recorded, with no September day exceeding 99. Beginning Sunday (9-3-2023), we have reached 99, 99, 99, and 100 on consecutive days.

August 2023 at DCA came in below the 1991-2020 normal, at 78.7 degrees, which was lower than August 2012 (81.0), but higher than August 2017 (77.4). So, the first eight months of 2023 slipped further behind 2012, with an average temperature of 62.96 degrees versus 64.22 for the first eight months of 2012. However, that 62.96 was barely below the 62.97 for the first eight months of 2017.

DCA _ NYC _ BOS __ ORD _ ATL _ IAH ___ DEN _ PHX _ SEA 1.3 1.9 1.3 3.0 0.0 3.6 3.6 0.4 0.1

Time for another update. Rainfall at DCA on August 12th has gone missing recently, as the last three years have totaled zero, a trace, and zero. On the other hand, rainfall the last three years on August 15th has totaled 0.24, 0.01, and 0.38 inches. However, no major storms have occurred on August 15th, and so the Top 10 rainiest days in DC history on August 12th or 15th remain entirely on August 12th. In the 13 years since I began tracking the difference in official DC precipitation on these two days, the major disparity that I found during 1871-2010 had not continued, which might suggest that disparity was an aberration. However, 13 years is too short a time period to conclude that, especially since August 12th has continued to be slightly wetter than August 15th, even though August 15th has recorded a few more rainy days during that recent period. Specifically, here are the 2011-2023 precipitation numbers for the two days at DCA: August 12: 2.74 inches total; 2 days with a trace, 4 days with measurable, 1 day with at least an inch, no days with 2+ inches. August 15: 2.37 inches total; 1 day with a trace, 7 days with measurable, 1 day with at least an inch, no days with 2+ inches. This is in contrast to the 1871-2010 precipitation numbers for the two days in DC: August 12: 40.95 inches total; 20 days with a trace, 51 days with measurable, 11 days with at least an inch, 5 days with 2+ inches. August 15: 11.12 inches total; 15 days with a trace, 45 days with measurable, 4 days with at least an inch, no days with 2+ inches.

July 2023 at DCA came in slightly above the 1991-2020 normal, at 81.6 degrees, but that was lower than July 2012 (84.0) and July 2017 (81.7). So, the first seven months of 2023 slipped further behind those two years, with an average temperature of 60.7 degrees, versus 61.8 for the first seven months of 2012 and 60.9 for the first seven months of 2017.

DCA _ NYC _ BOS __ ORD _ ATL _ IAH ___ DEN _ PHX _ SEA -1.2 -0.2 -0.6 0.4 -0.4 1.6 0.2 1.3 0.4

Despite the intense heat in much of the Northern Hemisphere this summer, DCA has yet to record its first 95-degree or higher day. The last time that failed to occur at DCA by July 21st was 2004, when the hottest temperature recorded all year was just 92.

June 2023 at DCA followed suit with May, averaging only 74.1 degrees -- tied for 76th all-time warmest June in DC history and 2.2 degrees below the 1991-2020 normal. As a result, January-June 2023 dropped further behind 2012, and also fell behind 2017, for the warmest first half of a calendar year in DC. Specifically, the first half of 2023 (181 days) averaged 57.1 degrees at DCA, behind 2012 (182 days) at 58.0 and 2017 (181 days) at 57.3.

DCA _ NYC _ BOS __ ORD _ ATL _ IAH ___ DEN _ PHX _ SEA -0.4 0.3 0.1 -1.3 -0.2 2.0 1.2 1.5 1.3

DCA _ NYC _ BOS __ ORD _ ATL _ IAH ___ DEN _ PHX _ SEA -0.3 0.1 -0.5 -0.5 0.0 0.8 -0.4 -2.1 0.7 98 96 95 96 96 102 99 117 92

May 2023 provided a sharp contrast to the prior four months at DCA, averaging just 65.0 degrees -- tied for 75th all-time warmest May in DC history and 2.2 degrees below the 1991-2020 normal. As a result, January-May 2023 dropped to the second warmest 5-month (151-day) start to a calendar year in DC history, at 53.7 degrees -- falling behind January-May 2012 (152 days) at 54.4 degrees.

April 2023 averaged 62.1 degrees at DCA, tied for third warmest April in DC history. Moreover, January-April 2023 is the warmest 4-month (120-day) start to a calendar year in DC history, at 50.8 degrees-- surpassing 2017 (also 120 days) at 50.2 degrees and 2012 (121 days) at 50.1 degrees.

DCA _ NYC _ BOS __ ORD _ ATL _ IAh _ DEN _ PhX _ SEA -2.1 -0.9 -0.2 -3.9 -1.7 1.2 0.9 -1.2 -0.7

I did have to update the numbers on February 1st, but since the snowfall at each airport remained below what every contestant had forecast, the relative outcome did not change one iota after the update.

Yes, January 2018 featured a lengthy arctic outbreak and it occurred during a Weak La Nina. January 4-7, 2018 at DCA featured a temperature range of 27/8. The four airports received 47.5 inches of snow that season, as compared with 48.1 inches durng the Moderate La Nina winter of 2021-22.

You're correct about the lack of precipitation -- just 9.19 inches at DCA during December 2022-March 2023, as opposed to 11.59 during December 2019-March 2020. December 2019 did not actually feature a true arctic outbreak, but the coldest day of the 2019-2020 winter season at DCA was on December 19, 2019, with a temperature range of 35/22. In contrast December 24, 2022 did feature a true arctic outbreak, with a DCA temperature range of 22/9.

You're welcome, and I'm sure that after your success the last two snow seasons, folks here will pay careful attention to your 2023-24 forecast.

I'm happy that this year's trophy is visible again -- maybe someone played an April Fool's joke on me.

See if this works:

If it's not as busy next year, it will be because of a complete shutout. Regarding the trophy, it loaded for me until I lost power at my home about two hours ago -- it is no longer loading. Perhaps a computer guru can fix. It should read the same as last year's trophy shown below, except the last two lines should be: 2022-23 Snowfall Contest/Little Village Wx