Data Date: January

Winter 2023-2024 – Very Warm and Very Wet Across Delaware

Posted on | by Dan Leathers

Winter Temperatures

Preliminary data indicates that the statewide average temperature in Winter was 40.2o F, which is 2.9°F above the 1991-2020 mean value of 37.3° F (Figure 1).  Winter’s temperature was the 9th warmest since records began in 1895.   

Winter Precipitation

Delaware’s statewide precipitation for Winter 2023-2024 averaged 15.83 inches, 5.78 inches above the 1991-2020 mean of 10.05 inches (Figure 2).  Winter’s precipitation was the 3rd wettest in the last 130 years.  In addition, Delaware saw four snowfall accumulations this year, with the largest accumulation of nearly six inches occurring on January 19th.  

Statewide Spatial Anomalies

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were positive across the entire state (Figure 3) with some locations seeing positive anomalies of more than 5° F for the winter in northern New Castle County.  Precipitation anomalies were strongly positive across the entire state, with the largest departures of more than eight inches found in southern Kent and northern Sussex counties (Figure 4). 

National Anomalies

Temperatures were above normal across the entire country (Figure 5).  Positive anomalies of over 9o F were found across the northern tier of the U.S. from North Dakota to Maine.  Positive precipitation departures were found along both the Pacific and Atlantic coasts (Figure 6) while below normal precipitation was scattered across other portions of the country.  The 500 hPa height pattern for Winter shows an anomalous jet stream ridge located over the northern U.S. and Canada, associated with the positive temperature anomalies found across these regions.

 

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Global map showing temperature anomalies from 1991-2020 normals.

Global Record-Warmth in January 2024

Posted on | by Tina Callahan
Global map showing temperature anomalies from 1991-2020 normals.
Global map showing temperature anomalies from 1991-2020 global temperature normals. Credit: NCEI

According to NCEI’s Global Climate Report for January 2024, the global surface temperature (both land and ocean) was 2.29°F above the 20th-century average.  This puts January as a record-breaking month — the previous record was set in January 2016. In addition, January 2024 is the 48th consecutive January with at least nominally higher temperatures than the 20th-century global average.  Looking only at ocean surface temperatures, January 2024 was at a record-high for the 10th consecutive month.  

Across much of the Northeast and western portion of the US, temperatures were above normal as well. (See Assessing the U.S. Climate in January 2024.)

While some areas of the globe experienced drier than normal conditions, January 2024 brought record-high precipitation over much of North America and was overall near global record levels.  Northern Hemisphere snow cover was average.

For more information on both National or Global conditions in January 2024, please use the following resources:

Rain drops fall upon a wooden surface

January 2024 – Warm and Wet Across Delaware

Posted on | by Dan Leathers

January Temperatures

Preliminary data indicates that the statewide average temperature in January was 37.6o F, which is 2.4o F above the 1991-2020 mean value of 35.2o F (Figure 1).  January’s temperature fell within the top one-third of readings over the last 130 years.   

January Precipitation

Delaware’s statewide precipitation for January 2024 averaged 6.12 inches, 2.77 inches above the 1991-2020 mean of 3.35 inches (Figure 2).  This month’s precipitation was the 8th highest for January since records began in 1895.

Statewide Spatial Anomalies

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were uniformly positive across the entire state (Figure 3) with some locations seeing positive anomalies of more than 3o F. 

Precipitation anomalies were positive across the entire state, with Sussex County recording some departures of more than four inches (Figure 4).

Delaware experienced two significant snowfall events during January.  On January 15th, snow fell across the entire state, with up to three inches observed across northern New Castle County.  A more significant snowfall occurred just a few days later, on January 19th.  Snow totals of over 5 inches were found across areas of New Castle and Kent counties, and the entire state was blanketed with snow.

National Anomalies

Temperatures were above normal across the Northeast United States and the Great Lakes Region (Figure 5), with anomalies reaching over 7o F across parts of Minnesota and Wisconsin.  Much of the central portion of the country, and the Pacific Northwest saw below normal temperatures during the month.  Precipitation departures were positive across the eastern one-third of the country (Figure 6) and along the northern Pacific coast. The remainder of the country had near normal amounts of precipitation. The 500 hPa height pattern for January matched the temperature departures very well with an anomalous jet stream trough located over the northwest and central United States, while ridging was found over the Northeast and Great Lakes (Figure 7).

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Long, thin plants with grey tone

January 2023 – Warm with Below Normal Precipitation Across Delaware

Posted on | by Dan Leathers

January Temperatures

Preliminary data indicates that the statewide average temperature in January was 43.1o F, which is 7.9o F above the 1991-2020 mean value of 35.2o F (Figure 1).  January 2023 was the third warmest since observations began in 1895.

January Precipitation

Delaware’s statewide precipitation for January 2023 averaged 2.41 inches, 0.94 inches below the 1991-2020 mean (Figure 2).  This month’s precipitation was in the bottom one-third of values since observations began in 1895.

Statewide Spatial Anomalies

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were uniformly positive across the entire state (Figure 3) with some stations seeing positive anomalies of up to 10.0o F.  Precipitation anomalies were uniformly negative across the entire state, with the largest negative anomalies found in Sussex County (Figure 4).   

National Anomalies

Temperatures were much above normal across the eastern one-half of the United States and below normal across most of the western portion of the country (Figure 5).  Precipitation departures were mixed across the country, with the largest positive precipitation anomalies found in California, continuing the relief of drought conditions there (Figure 6).

The 500 hPa height pattern for January shows a jet stream trough over the western United States and a jet stream ridge over the east, contributing to the temperature anomalies across each region (Figure 7).

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January 2022 – Cold and Moist Conditions Across Delaware

Posted on | by Dan Leathers

January Temperatures

Preliminary data indicates that the statewide average temperature in January was 32.2° F, which is 3.0° F below the 1991-2020 mean value of 35.2° F (Figure 1).  Although below normal, January’s average temperature was in the middle 33% of all years since observations began in 1895.  

January Precipitation

Delaware’s statewide precipitation for January 2022 averaged 4.53 inches, 1.18 inches above the 1991-2020 mean (Figure 2).  This placed this month’s precipitation as the 23rd highest  January precipitation total since records began in 1895.

Statewide Spatial Anomalies

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were uniformly below normal across the entire State, with many stations seeing negative temperature anomalies of greater than 3° F (Figure 3).  Snowfall events on January 3rd and January 29th left significant snow accumulations, especially across central and southern Delaware, contributing to the higher than normal monthly precipitation.

National Anomalies

Temperatures were below normal across the eastern two-thirds of the United States, with the largest negative temperature anomalies found across the northern tier.  The western one-third of the country saw positive anomalies except in portions of the Pacific Northwest (Figure 4).  Precipitation anomalies varied greatly across the country (Figure 5), with excessively dry conditions across California, Nevada and much of the Great Plains.  Wet conditions were found across the Ohio Valley and the Mid-Atlantic regions.  The 500 hPa height pattern for January shows a strong jet stream trough located over eastern North America and a strong jet stream ridge over the western United States contributing to the temperature extremes across those regions (Figure 6).

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Snow-covered autumn leaves

January 2021 – Warm and Dry Across Delaware

Posted on | by Dan Leathers

January Temperatures

Preliminary data indicates that the statewide average temperature in January was 37.1° F, which is 3.0° F above the 1981-2010 mean value of 34.1° F (Figure 1).  January 2021 was the 28th warmest since observations began in 1895, placing it in the top one-third of all Januarys.

January Precipitation

Delaware’s statewide precipitation for January 2021 averaged 2.33 inches, 0.99 inches below the 1981-2010 mean (Figure 2).  This placed this month’s precipitation total as the 25th lowest of all Januarys since 1895, tied with January 1969.  Snowfall totaled 2.5 inches for the month at the Wilmington/New Castle County Airport, and this fell on the last day of the month.  Normal snowfall for January is 5.9 inches. 

Statewide Spatial Anomalies

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were positive at all stations, with the largest anomalies found across New Castle County (Figure 3).  Precipitation was generally below normal throughout the State.  

National Anomalies

Temperatures were above normal across the majority of the United States, with the largest temperature anomalies (10° F – 13° F) found across the north-central portion of the country (Figure 4).  Only the southwest United States saw below normal January temperatures.  Precipitation anomalies varied greatly across the country with particularly heavy precipitation across the central United States, while the northern tier of the country and Florida saw very dry conditions (Figure 5).  The 500 hPa height pattern for January shows a very strong jet stream ridge across northeastern North America resulting in the warm conditions across the northern portions of the country (Figure 6). 

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Bethany Beach with a colorful sky

January 2020 – Very Warm With Near Normal Precipitation

Posted on | by Dan Leathers

January Temperatures

Preliminary data indicates that the statewide average temperature in January was 40.1°F, which is 6.0°F above the 1981-2010 mean value of 34.1°F (Figure 1). January 2020 was tied with January of 2007 as the 11th warmest since 1895 in Delaware.

January Precipitation

Delaware’s statewide precipitation for January 2020 averaged 3.20 inches, 0.12 inches below the 1981-2010 mean (Figure 2). This placed the January 2020 precipitation amount in the “normal” category for the month.

Statewide Spatial Anomalies

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were uniformly above normal throughout the State (Figure 3), with some stations more than 6°F above the 30-year mean. Precipitation was below normal across Kent and Sussex Counties, while several stations in New Castle County had small positive precipitation departures (Figure 4).

National Anomalies

Temperatures were above normal across the majority of the U.S, with some departures reaching 7° to 10°F in the Northeast (Figure 5). Precipitation varied greatly across the U.S. with very wet conditions across the central States while the extreme southwest remained very dry (Figure 6). The 500 hPa height pattern for January showed a ridge dominating the eastern half of the country (Figure 7), bringing the warm conditions to our region.

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Snow flake up close

January 2019 – Temperature and Precipitation Near Normal Across Delaware

Posted on | by Dan Leathers

 

 

January Temperatures

Preliminary data indicates that the statewide average temperature in January was 34.6°F, which is 0.5°F above the 1981-2010 mean value of 34.1°F (Figure 1). Delaware’s January temperatures were considered “normal” for the month in comparison to all data going back to 1895, not falling within the bottom or top one-third of January values in the last 125 years.

January Precipitation

Delaware’s statewide precipitation for January 2019 averaged 3.45 inches, 0.13 inches above the 1981-2010 mean (Figure 2). Snowfall was slightly below normal during the month in northern Delaware with 5.6 inches of snow recorded at the Wilmington – New Castle County Airport (normal is 6.6 inches). Moderately heavy snow fell in central and southern Delaware on the 13th with up to four inches recorded in much of Kent and Sussex counties.

Statewide Spatial Averages

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were near or below normal across the entire state (Figure 3). Precipitation departures varied greatly, but were uniformly small (Figure 4), with most stations seeing departures of 1 inch or less.

National Anomalies

Temperature anomalies across the U.S. were generally small, with much of the northwest experiencing above normal temperatures along with much of the southeast. The upper mid-west and Great Lakes regions experienced below normal temperatures during the month of January (Figure 5). Precipitation was generally above normal for much of the northeast quadrant of the country, while much of the northern tier of the U.S. was drier than normal (Figure 6).

 

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Branches frozen in the cold

Conditions Continue Cool and Dry Across Delaware in January 2018

Posted on | by Dan Leathers

 

 

January Temperatures

Preliminary data indicates that the statewide average temperature in January was 32.6°F, which is 1.5°F below the 1981-2010 mean value of 34.1°F (Figure 1). This was the third month in a row with
temperatures at or below normal across Delaware. Most of the United States east of the Rocky Mountains shared in Delaware’s colder than normal January temperatures (Figure 2).

January Precipitation

Delaware’s statewide precipitation for January 2018 averaged 2.97 inches, 0.35 inches below the 1981-2010 mean (Figure 3). Snowfall was also below normal during the month in northern Delaware with
only 3.5 inches of snow recorded at the Wilmington – New Castle County Airport . However, a storm on January 4th brought heavy snowfall to Sussex County, with many locations receiving more than
10 inches of snow.

Statewide Spatial Averages

Data from the Delaware Environmental Observing System (DEOS) show that temperature departures were uniformly below normal across the entire State (Figure 4). Precipitation departures were
below normal at all but a few scattered stations (Figure 5), with most stations seeing departures of 1 inch or less.

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Dry plant with muted tan colors

Very Warm and Dry Conditions Characterize the 2016-2017 Winter Season Across Delaware

Posted on | by Dan Leathers

 
 

Winter Temperatures

Preliminary data indicates that winter temperatures were far above the 30-year “normal” during the winter season. The statewide mean winter temperature of 40.8°F was 4.5°F above the 1981-2010 mean value of 36.3°F (Figure 1). This made winter 2016-2017 the 5th warmest since records began in 1895, and the second winter in a row in the top 5 warmest on record.

Winter Precipitation

The statewide mean precipitation of 7.19 inches was 2.57 inches below the 1981-2010 normal of 9.76 inches, and was the 17th driest winter season since records began in 1895 (Figure 2).

Statewide Spatial Averages

Data from the Delaware Environmental Observing System (DEOS) show that winter temperatures across the entire State were above normal, with the largest anomalies found in northern Sussex and northern New Castle counties in Delaware and in Chester County, PA (Figure 3).

Winter precipitation totals were significantly below normal across the entire State, with the driest conditions along the Sussex County coast (Figure 4). At the New Castle County Airport, only 5.6 inches of snow fell during the December through February winter season, a value far below the 1981-2010 mean of 17.7 inches. During March, another 3.4” of snow fell in northern Delaware bringing the total for the entire snow season (November through April) to 9.0 inches.

 

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