National Weather Service United States Department of Commerce
Water Temperature Climatology, North Inlet-Winyah Bay, South Carolina

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Winyah Bay is a large, natural embayment near Georgetown, South Carolina.  The Pee Dee and Waccamaw Rivers both drain to the Atlantic Ocean through Winyah Bay.  Water temperatures can change much more quickly here than in the ocean due to tidal flows, shallow water depth, and rainfall-induced drainage from nearby land.  At low tide the shallow water is quickly heated by the sun during the day, and can become quite cold during a long winter night.  Data presented here should give a good approximation of water temperatures in most South Carolina saltmarshes.

 

Average Water Temperatures for North Inlet-Winyah Bay, SC

January

February

March

April

May

June

1-10

11-20

21-31

1-10

11-20

21-29

1-10

11-20

21-31

1-10

11-20

21-30

1-10

11-20

21-31

1-10

11-20

21-30

51

51

50

51

53

55

57

60

62

65

67

70

73

75

78

80

82

83

 

July

August

September

October

November

December

1-10

11-20

21-31

1-10

11-20

21-31

1-10

11-20

21-30

1-10

11-20

21-31

1-10

11-20

21-30

1-10

11-20

21-31

84

84

85

84

84

83

81

80

78

75

72

68

64

61

59

56

54

52

Average values are given for early (1st-10th), mid (11th-20th), and late (21st-31st) each month.

 

Detailed Water Temperature Statistics for North Inlet-Winyah Bay, SC

Box and Whisker statistical plot.  Colored boxes indicate the 25th through 75th percentiles, with the red/blue center of each box indicating the mean (average) value.  The black whiskers indicate the highest and lowest temperatures ever observed during each roughly 10 day time period throughout the year.

Box and whisker statistical plot of water temperatures for North Inlet-Winyah Bay, SC

 

Statistical table of water temperature data.  In addition to mean, highest and lowest values for each time period, various percentiles are displayed.  Sigma (σ, standard deviation) values help define the distribution of the data.

 

January

February

March

April

May

June

 

1-10

11-20

21-31

1-10

11-20

21-29

1-10

11-20

21-31

1-10

11-20

21-30

1-10

11-20

21-31

1-10

11-20

21-30

Highest

68.2

68.4

70.9

71.1

67.8

72.3

75.7

76.3

81.3

81.3

87.3

86.5

88.7

88.5

91.2

94.1

97.2

94.6

+2σ

63.1

62.4

62.4

63.0

62.8

66.4

68.2

70.3

74.7

76.3

79.5

81.5

84.0

83.3

87.3

89.4

90.9

91.2

Upper 5%

61.5

60.6

60.6

60.6

61.2

64.0

66.4

68.5

72.5

74.3

76.8

79.2

82.1

81.9

85.6

87.6

89.2

89.8

Upper 10%

59.4

58.5

57.9

58.3

59.0

61.5

64.2

66.8

70.0

72.0

74.3

76.6

79.9

80.2

83.7

85.6

87.3

88.2

+1σ

57.7

56.7

56.1

56.5

57.6

59.7

62.4

65.1

67.8

70.2

72.5

75.2

78.1

79.0

82.0

84.2

85.8

86.7

Upper 25%

55.8

54.7

53.8

54.7

55.8

58.1

60.4

63.1

65.7

68.4

70.5

73.4

76.1

77.4

80.6

82.8

84.2

85.3

MEAN

51.2

50.6

50.0

51.4

52.6

55.3

56.9

59.6

61.9

64.9

67.4

70.4

73.0

74.7

77.8

80.2

82.2

83.1

Lower 25%

46.4

46.6

45.9

47.8

49.3

52.2

53.1

55.8

57.9

61.2

63.9

67.1

69.6

72.0

74.8

77.7

79.7

80.6

-1σ

46.0

46.0

45.5

47.7

48.9

51.8

52.7

55.4

57.6

60.8

63.5

66.7

69.3

71.6

74.5

77.5

79.5

80.4

Lower 10%

42.4

42.8

43.0

45.0

46.6

50.0

50.4

52.9

54.7

58.5

61.2

64.8

66.7

69.8

72.3

75.2

77.9

78.6

Lower 5%

40.3

40.6

41.4

43.0

45.0

48.0

48.6

51.3

53.4

57.2

59.7

63.3

64.6

68.5

70.5

73.2

76.6

77.0

-2σ

38.7

39.4

39.9

41.4

43.9

46.2

46.9

49.3

52.2

55.9

58.1

61.5

62.1

67.1

68.9

70.0

75.4

75.9

Lowest

34.3

34.5

32.5

36.0

37.6

40.8

41.4

42.6

45.1

51.6

53.4

56.5

54.9

60.3

64.8

63.7

70.7

71.2

 

 

July

August

September

October

November

December

ANN

 

1-10

11-20

21-31

1-10

11-20

21-31

1-10

11-20

21-30

1-10

11-20

21-31

1-10

11-20

21-30

1-10

11-20

21-31

 

Highest

95.7

94.5

97.7

99.0

96.3

95.7

92.1

91.4

89.6

87.3

80.8

82.2

79.2

75.4

72.3

71.8

72.0

69.6

99.0

+2σ

91.6

91.2

92.5

92.1

91.4

90.5

88.5

86.5

85.3

82.6

78.8

76.8

75.0

70.0

67.6

66.7

65.3

63.1

88.5

Upper 5%

90.0

89.8

91.0

90.9

90.1

89.1

87.1

85.1

84.0

81.7

77.7

75.4

72.3

68.4

66.6

65.3

63.1

61.2

86.4

Upper 10%

88.2

88.3

89.4

89.2

88.5

87.4

85.5

83.8

82.6

80.4

76.6

73.8

70.5

66.7

65.5

63.9

61.3

59.0

84.4

+1σ

86.9

87.1

88.0

88.0

87.4

86.4

84.6

82.9

81.7

79.2

75.7

72.1

69.4

65.1

64.3

61.7

59.5

57.4

82.8

Upper 25%

85.6

86.0

86.5

86.5

86.2

85.3

83.5

82.0

80.6

77.7

74.5

70.7

67.6

63.9

63.0

59.4

57.7

55.4

80.4

MEAN

83.8

84.1

84.6

84.5

84.1

83.4

81.5

79.6

78.0

74.8

72.0

67.7

64.4

61.0

58.8

55.8

54.2

51.7

68.4

Lower 25%

81.7

82.2

82.2

82.4

82.0

81.3

79.3

77.2

75.6

72.1

69.6

64.9

61.2

58.1

55.0

52.0

50.7

48.0

57.2

-1σ

81.3

81.9

82.0

82.0

81.9

81.0

79.2

76.8

75.4

71.8

69.3

64.4

61.0

57.9

54.5

51.4

50.4

47.7

56.3

Lower 10%

79.9

80.4

80.6

80.4

79.9

79.3

77.2

74.7

73.2

69.4

66.9

61.2

58.8

55.2

51.8

48.7

48.0

43.9

50.5

Lower 5%

78.8

79.2

79.3

79.0

77.9

78.1

75.7

73.6

71.4

67.8

65.3

59.7

57.2

53.4

50.2

47.1

45.5

42.1

47.5

-2σ

77.9

77.7

78.1

77.5

76.1

77.0

74.5

72.1

70.0

65.7

63.7

57.9

55.9

51.8

48.5

45.5

41.9

40.6

44.6

Lowest

74.5

71.8

74.3

72.7

73.0

73.8

71.4

67.5

66.0

58.6

58.8

48.9

51.8

45.5

43.9

40.1

33.4

35.1

32.5

 

After quality control, a total of 430,437 individual water temperature observations were available to calculate the values used in this climatology.  Data was collected by the Baruch Marine Lab at the North Inlet-Winyah Bay National Estuarine Research Reserve over the period 1996 through 2013.  Current water temperature data for this site is available here; weather and tide data is available here.

 

Page Author and Statistical Analysis:  Tim Armstrong
Page Created:  July 16, 2015
Last Updated:  July 16, 2015