Data Date: August

Drops of water on bright green grass

Temperature and Precipitation Both Above Normal Across Delaware During 2015

Posted on | by Dan Leathers
 
 
 

Annual Temperatures

Statewide mean annual temperature in 2015 was 56.4°F according to preliminary data from the National Climatic Data Center (NCDC). This was 1.0°F above the 1981-2010 normal of 55.4°F (Figure 1) and was the 11th warmest year in Delaware since 1895.

Monthly temperatures varied greatly throughout the year (Figure 2). The first three months of 2015 saw much below normal temperatures, including the 6th coldest February since 1895. The last nine months of the year saw above normal temperatures, except for October, which was slightly below normal. Tremendous warmth ended the year with December temperatures averaging 12.4°F above the 1981-2010 mean. December 2015 was the warmest December on record, smashing the old record by 6.1°F.

Annual Precipitation

Statewide precipitation in 2015 averaged 46.37 inches, 2.04 inches above the 1981-2010 mean of 44.33 inches (Figure 3).

Monthly precipitation anomalies varied between positive and negative throughout the year, with seven months of below normal and five months of above normal precipitation (Figure 4). June saw the largest precipitation anomaly of 5.30 inches above the 30-year normal, helping to push the annual value above the long-term mean.

Statewide Spatial Averages

According to data from the Delaware Environmental Observing System (DEOS; deos.udel.edu), mean annual temperature anomalies varied across Delaware (Figure 5). Northern New Castle County, much of Sussex County, southern Kent County and Chester County, PA all experienced above normal temperatures for the year. Coastal Sussex County and western portions of News Castle and Kent counties saw below normal mean annual temperatures.

Precipitation across the region varied substantially in 2015, ranging from just under 40 inches to greater than 50 inches at several locations across the State (Figure 6).

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Beach in Summer

Seasonable Temperatures and Dry Conditions Characterize August 2015 Delaware Climate

Posted on | by Dan Leathers
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Figure 1. Delaware statewide mean August temperature (°F) 1895-2015.

 
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Figure 2. Delaware statewide mean August precipitation (inches) 1895-2015.

 

August Temperatures

Preliminary data indicates that the statewide average temperature in August was 74.9°F, equal to the 1981-2010 average for the month (Figure 1). Even with near normal temperatures, August 2015 was the warmest August in the last three years.

August Precipitation

Delaware’s statewide precipitation for August 2015 averaged only 2.81 inches, 1.31 inches below the 1981-2010 mean (Figure 2). August 2015 was the driest August since 2008 across the First State.

DEOS Station Observations

Temperature anomalies varied across the State, with the largest negative departures occurring in Sussex County, and the largest positive departures occurring in the Wilmington area (Figure 3). Precipitation was below normal across nearly the entire State, with deficits of more than two inches found in each County (Figure 4).

August 2015 average temperature departures from the 1981-2010 mean based upon DEOS station data.
Figure 3. August 2015 average temperature departures (°F) from the 1981-2010 mean based upon DEOS station data.

 
August 2015 precipitation departures (inches) from the 1982-2010 mean based upon DEOS station data.
Figure 4. August 2015 precipitation departures (inches) from the 1981-2010 mean based upon DEOS station data.
Ocean Waves

Summer 2015 Brings Warm and Moist Conditions to Delaware

Posted on | by Dan Leathers
Posted on Wed 10/14/15

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Figure 1. Delaware statewide mean Summer temperature (°F) 1895-2015.
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Figure 2. Delaware statewide Summer precipitation (inches) 1895-2015.

Summer Temperatures

Preliminary data indicates that summer temperatures were just above the 30-year “normal” during 2015. The statewide mean summer temperature of 75.1°F was 0.6°F above the 1981-2010 mean value of 74.5°F (Figure 1). Monthly temperatures during the season were all above normal, with June recording the largest departure of 1.4°F.

Summer Precipitation

The statewide mean precipitation of 15.17 inches was 3.17 inches above the 1981-2010 normal of 12.0 inches, and was the 3rd year in a row with above normal Summer rainfall (Figure 2). Heavy rainfall across the State during June (9.03 inches) accounted for the seasonal departure, as both July and August saw below normal precipitation.

Statewide Spatial Averages

Data from the Delaware Environmental Observing System (DEOS) show that temperature anomalies across the State varied during the Summer season depending upon location (Figure 3).

Rainfall was above normal across much of the State, except for portions of Kent and Sussex counties where negative precipitation departures of up to 3.0 inches were found (Figure 4). The fact that much of our summer precipitation falls in showers and thunderstorms can cause large spatial variations in precipitation during the summer season.

Summer 2015 average temperature departures from the 1981-2010 mean based upon DEOS station data.

Figure 3. Summer 2015 average temperature departures (°F) from the 1981-2010 mean based upon DEOS station data.
Summer 2015 precipitation departures (inches) from the 1981-2010 mean based upon DEOS station data.

Figure 4. Summer 2015 precipitation departures (inches) from the 1981-2010 mean based upon DEOS station data.
 
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Cars in Wilmington

Cool Temperatures and Near Normal Precipitation Characterize Delaware’s Climate During 2014

Posted on | by Dan Leathers
Posted on Mon 01/26/15 , Updated 02/01/16

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Figure 1. Delaware statewide annual mean temperature (°F) 1895-2014.
December monthly temperature anomalies.

Figure 2. Delaware monthly temperature anomalies.

Annual Temperatures

Statewide mean annual temperature in 2014 was 54.8°F according to preliminary data from the National Climatic Data Center (NCDC). This was 0.6°F below the 1981-2010 normal of 55.4°F (Figure 1) and was the coolest year in Delaware since 2003.

Monthly temperatures varied greatly throughout the year (Figure 2). The first four months of 2014 saw much below normal temperatures accompanied by heavy snowfall across the State. Although late spring and early summer saw a return to above normal temperatures, the late summer climate was cooler than normal, a welcome respite from the summer heat for many residents. The year ended with a return to warmth in three of the last four months.

Annual Precipitation

Statewide precipitation in 2014 averaged 43.49 inches, 0.84 inches below the 1981-2010 mean of 44.33 inches (Figure 3).

Monthly precipitation anomalies varied between positive and negative throughout the year, with six months of above normal and six months of below normal precipitation (Figure 4). None of the monthly precipitation anomalies were large, leading to the near normal annual total.

Statewide Spatial Averages

According to data from the Delaware Environmental Observing System (DEOS; deos.udel.edu), mean annual temperatures were below normal across the entire State with the largest negative anomalies found in coastal Sussex County (Figure 5).

Precipitation across the region varied substantially in 2014, ranging from just under 39 inches to greater than 50 inches across the region (Figure 6).

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Figure 3. Delaware statewide annual precipitation (inches) 1895-2014.
Delaware monthly precipitation anomalies.

Figure 4. Delaware monthly precipitation anomalies.
2014 mean annual temperature departures from the 1981-2010 mean based upon DEOS station data.

Figure 5. 2014 mean annual temperature departures from the 1981-2010 mean based upon DEOS station data.
2014 annual precipitation totals based upon DEOS station data.

Figure 6. 2014 annual precipitation totals based upon DEOS station data.
 
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Leaves in Rain

Delaware Climate Continues Cool and Wet During August 2014

Posted on | by Dan Leathers

 

August Temperatures

Preliminary data indicates that the statewide average temperature in August was 72.4°F, 2.5°F below the 1981-2010 normal of 74.9°F (Figure 1) and the coolest August since 1994.

August Precipitation

Delaware’s statewide precipitation for August 2014 averaged 5.09 inches, 0.97 inches above the 1981-2010 mean (Figure 2). This was the 4th August in a row to see above normal precipitation across the “First State”.

Statewide Spatial Averages

Data from the Delaware Environmental Observing System (DEOS) shows that the mean August temperatures across Delaware were consistently below normal across the entire state. No DEOS station experienced above normal temperatures during the month, and several stations were more than 5°F below their August normal (Figure 3).

Rainfall totals varied greatly across the region. The large difference in rainfall values is due to the fact that most August precipitation falls in small-scale showers and thunderstorms (Figure 4). Rainfall totals ranged from over 5 inches to less than 2 inches depending upon the specific location across Delaware and Chester County, PA.

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Rainbow over Bridge

2013 Warm and Wet Across Delaware

Posted on | by Dan Leathers

Delaware’s 2013 climate was characterized by slightly warmer than normal temperatures and above normal precipitation values.

 

Annual Temperature

Statewide mean annual temperature in 2013 was 56.5°F according to preliminary data from the National Climatic Data Center (NCDC). This was 0.7°F above the 1981-2010 normal of 55.8°F (Figure 1) and was the fourth year in a row with above normal temperatures. However, this year was nearly 2.0°F cooler than 2012’s all time high value of 58.4°F.

Annual Precipitation

Statewide precipitation in 2013 averaged 49.93 inches, 4.07 inches above the 1981-2010 mean of 45.86 inches (Figure 2). Most areas of the state saw substantially above normal precipitation during the summer months, making the summer of 2013 the 5th wettest on record since 1895.

Statewide Spatial Averages

According to data from the Delaware Environmental Observing System (DEOS; deos.udel.edu), mean annual temperatures were above normal across portions of New Castle, western Kent and Sussex counties, and across Chester County, PA (Figure 3). Mean annual temperatures were below normal across the remainder of the State.

Precipitation was much above normal in all locations except southwestern Kent County and portions of Chester County, PA (Figure 4). The largest positive precipitation departures were found along the eastern portions of Sussex County where some locations received 10 inches more precipitation than normal.

Images
Tree on River

Delaware Experiences Cool Temperatures and Above Normal Rainfall During August 2013

Posted on | by Dan Leathers
Posted on Wed 09/18/13 , Updated 09/24/13

Cooler than normal temperatures and above normal rainfall characterized Delaware’s Climate during August 2013.

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Figure 1. Delaware statewide mean August temperature (°F) 1895-2013.
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Figure 2. Delaware statewide August precipitation (inches) 1895-2013.

August Temperatures

Preliminary data indicates that the statewide average temperature in August was 74.5°F. This is 0.8° F below the 1981-2010 normal of 75.3°F (Figure 1) and marks the second month this year with below normal temperatures (March also had below normal temperature).

August Precipitation

Delaware’s statewide precipitation for August 2013 averaged 4.94”, which is 0.69” above the 1981-2010 mean of 4.25” (Figure 2). Rainfall totals varied across the state ranging from nearly 8” in portions of Sussex County to less than 4” across central portions of Kent County.

Statewide Spatial Averages

Data from the Delaware Environmental Observing System (DEOS) shows that average August temperatures across Delaware were below normal throughout the entire state with eastern Sussex County and Kent County recording the largest negative anomalies (Figure 3). In general, the magnitude of the cooler than normal conditions increased moving from north to south through Delaware.

Average maximum temperatures were far below normal for nearly the entire state, while minimum temperatures were cooler than normal in most locations, except across portions of western Sussex County and Chester County, PA where some stations actually recorded warmer than normal minimum temperatures.

Precipitation was above normal across most of the State except for a large area of below normal precipitation in Kent County and far western Sussex County (Figure 6).

August 2013 average temperature departures from the 1981-2010 mean based upon DEOS station data

Figure 3. August 2013 average temperature departures from the 1981-2010 mean based upon DEOS station data.
Delaware August 2013 maximum temperature departures from the 1981-2010 mean based upon DEOS station data

Figure 4. August 2013 maximum temperature departures from the 1981-2010 mean based upon DEOS station data
Delaware August 2013 minimum temperature departures from the 1981-2010 mean based upon DEOS station data

Figure 5. August 2013 minimum temperature departures from the 1981-2010 mean based upon DEOS station data
Delaware August 2013 precipitation departures from the 1981-2010 mean based upon DEOS station data

Figure 6. August 2013 precipitation departures from the 1981-2010 mean based upon DEOS station data
 
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Beach in Summer

Delaware’s Summer 2013 Update

Posted on | by Dan Leathers
Posted on Mon 10/14/13

Above normal temperatures and heavy rainfall characterized Delaware’s Climate during summer 2013.

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Figure 1. Delaware statewide mean Summer temperature (°F) 1895-2013.
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Figure 2. Delaware statewide Summer precipitation (inches) 1895-2013.

Summer Temperatures

Preliminary data indicates that Delaware had its 4th summer in a row with above normal temperatures. The Statewide mean summer temperature of 76.0 °F was 1.1 °F above the 1981-2010 normal of 74.9°F. This summer’s warmer than normal conditions placed it as the 11th warmest summer since records began in 1895 (Figure 1).

Summer Precipitation

Warm temperatures were accompanied by extremely wet conditions across the state during the summer season. The statewide mean precipitation of 21.41” was 8.96” above the 1981-2010 normal of 12.45”, and was the wettest summer since 21.8” of rain fell during the summer of 1989 (Figure 2), and the 5th wettest summer since records began in 1895.

Statewide Spatial Averages

Data from the Delaware Environmental Observing System (DEOS) show that mean summer temperatures across the state varied from generally warmer than normal conditions in northern New Castle, southern Kent and northern Sussex counties to below normal, especially along coastal regions (Figure 3). Mean summer maximum temperatures were generally below normal across the entire state (Figure 4), while mean summer minimum temperatures were above normal in most locations (Figure 5). The lower maximum temperatures and higher minimum temperatures are consistent with the heavy rainfall the state saw during the summer.

All stations in the DEOS network recorded above normal precipitation values during summer 2013. Precipitation anomalies reached greater than ten inches in portions of northern New Castle County and in eastern Sussex County. The driest areas of the state were found in southwestern Kent and northwestern Sussex Counties (Figure 6). Even in these locations, precipitation was above normal for the summer season.

Summer 2013 average temperature departures from the 1981-2010 mean based upon DEOS station data

Figure 3. Summer 2013 average temperature departures from the 1981-2010 mean based upon DEOS station data.
Delaware Summer 2013 maximum temperature departures from the 1981-2010 mean based upon DEOS station data

Figure 4. Summer 2013 maximum temperature departures from the 1981-2010 mean based upon DEOS station data
Delaware Summer 2013 minimum temperature departures from the 1981-2010 mean based upon DEOS station data

Figure 5. Summer 2013 minimum temperature departures from the 1981-2010 mean based upon DEOS station data
Delaware Summer 2013 precipitation departures from the 1981-2010 mean based upon DEOS station data

Figure 6. Summer 2013 precipitation departures from the 1981-2010 mean based upon DEOS station data
 
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Sunrise in Delaware

2012 is Warmest Year on Record for Delaware Since 1895

Posted on | by Dan Leathers
Posted on Sat 02/23/13 , Updated 04/05/13

Statewide Mean Annual Temperature 1895-2012

Figure 1. Delaware statewide mean annual temperature (°F) 1895-2012.

Preliminary data indicates that Delaware saw its warmest year on record during 2012.

The mean annual temperature of 58.8 ° F was 3.9 ° F above the 1895 – 2012 mean temperature, making it the warmest year since records began in 1895.

This year broke the previous record of 58.1 ° F set in 2011.

The six warmest years on record have all occurred since 1990 (Figure 1).

The warm temperatures were accompanied by very dry conditions across the state during the year. The statewide mean precipitation of 34.53” was 10.05” below the 1895-2012 statewide mean, making 2012 the 6th driest year since records began in 1895 (Figure 2).

Conditions in Delaware mirrored those across much of the United States.

The contiguous 48 states had their highest temperature and 15th driest year since 1895 (Figures 3 and 4).

 
Statewide Annual Precipitation 1895-2012

Figure 2. Delaware statewide mean precipitation (inches) 1895-2012.
US temperature anomalies for 2012

Figure 3. Temperature anomalies (°F) across the contiguous United States. Map provided by the National Climatic Data Center.
US temperature anomalies for 2012

Figure 4. Precipitation anomalies (inches) across the contiguous United States. Map provided by the National Climatic Data Center.
 
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