DC's Most Extreme Daily High/Low Temperature Differentials

[RodneyS]

The narrow differential between the high and low temperatures on September 6, 2011 (67/64) at DCA caused me to wonder when the last time was that we had such a narrow differential. The answer, I believe, is March 14, 2010, when the temperature range was 52/49. Prior to that, we had a two-degree differential (67/65) on September 17, 2009 and a one-degree differential (32/31) on February 5, 1946. The only other one degree differential I could find was 31/30 on December 3, 1904. However, there was a recorded zero-degree differential (31/31) on January 1, 1873! Looking at the previous day's range, however, leads me to believe that the early morning high temperature on New Year's Day 1873 was not recorded. December 31, 1872 shows a range of 45/34. If that is accurate, January 1, 1873 would have begun with a temperature of at least 34. Perhaps the recorder did not check the temperature until it had already fallen to 31 on New Year's Day.

On the high side, the largest differential occurred on March 22, 1907, with a temperature range of 90/40 -- winter and summer in one day.

[WxUSAF]

Good stuff, thanks for the post.

[FrederickWX]

The narrow differential between the high and low temperatures on September 6, 2011 (67/64) at DCA caused me to wonder when the last time was that we had such a narrow differential. The answer, I believe, is March 14, 2010, when the temperature range was 52/49. Prior to that, we had a two-degree differential (67/65) on September 17, 2009 and a one-degree differential (32/31) on February 5, 1946. The only other one degree differential I could find was 31/30 on December 3, 1904. However, there was a recorded zero-degree differential (31/31) on January 1, 1873! Looking at the previous day's range, however, leads me to believe that the early morning high temperature on New Year's Day 1873 was not recorded. December 31, 1872 shows a range of 45/34. If that is accurate, January 1, 1873 would have begun with a temperature of at least 34. Perhaps the recorder did not check the temperature until it had already fallen to 31 on New Year's Day.

On the high side, the largest differential occurred on March 22, 1907, with a temperature range of 90/40 -- winter and summer in one day.

The 90/40 temp differential is pretty remarkable! It would be interesting to see what the largest differential has been during the autumn. I would guess that it wouldn't be anywhere near as extreme, given that Spring still has a ton of cold air available at a time where heat is also building. In Autumn, the heat is waning, but the pool of cold air hasn't yet built to significant levels.

[RodneyS]

The 90/40 temp differential is pretty remarkable! It would be interesting to see what the largest differential has been during the autumn. I would guess that it wouldn't be anywhere near as extreme, given that Spring still has a ton of cold air available at a time where heat is also building. In Autumn, the heat is waning, but the pool of cold air hasn't yet built to significant levels.

If you're referring to meteorological autumn, I believe that the record differential is 42 degrees, achieved three different times: October 19, 1901 (78/36); October 31, 1909 (79/37); and November 12, 1911 (70/28).

If you're referring to astronomical autumn, I believe that the record differential is 47 degrees, achieved December 15, 1901 (64/17).

[MN Transplant]

The narrow differential between the high and low temperatures on September 6, 2011 (67/64) at DCA caused me to wonder when the last time was that we had such a narrow differential. The answer, I believe, is March 14, 2010, when the temperature range was 52/49. Prior to that, we had a two-degree differential (67/65) on September 17, 2009 and a one-degree differential (32/31) on February 5, 1946. The only other one degree differential I could find was 31/30 on December 3, 1904. However, there was a recorded zero-degree differential (31/31) on January 1, 1873! Looking at the previous day's range, however, leads me to believe that the early morning high temperature on New Year's Day 1873 was not recorded. December 31, 1872 shows a range of 45/34. If that is accurate, January 1, 1873 would have begun with a temperature of at least 34. Perhaps the recorder did not check the temperature until it had already fallen to 31 on New Year's Day.

On the high side, the largest differential occurred on March 22, 1907, with a temperature range of 90/40 -- winter and summer in one day.

Nice stats. I had considered looking that up myself.