Hammocks Beach State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Hammocks Beach State Park clear sky chart from 2005-11-06 to 2024-12-24.

This page is a summary of past forecasts. Even though it's based only on forecasts, some people use these pages as clue to a site's climate. But climate data based on actual observation should be preferred (if you can find it!).

Cloud, Transparency and Seeing forecasts are summarized individually. But because good observing conditions require a combination of minimum cloud cover, transparency and seeing, the individual forecast summaries can be difficult to interpret. The observing conditions section counts the combinations of conditions needed for common types of astronomical observation.

Observing Conditions

The following tables count the occurrence of the combinations of forecast and darkness conditions needed for different observations. Conditions are rated by by what percentage of the hours the observation would likely be attempted are usable.

Observation Type	Minimum conditions for hour to be usable				Out of hours
	Clear of Clouds	Transparency	Seeing	Sky Brightness
Planetary:	50%	(no limit)	Average	(no limit)	Nighttime Hours
Deep Sky:	70%	Average	(no limit)	5.9	Nighttime Hours
CCD Imaging:	70%	Below Average	Poor	(no limit)	Nighttime Hours

Percentages are of nighttime hours per month, or per year, when a particular observing conditions was met. Deep Sky percentages never exceed 50% because the moon is up half the time. Deep sky percentages are much lower for charts at high latitudes because of fewer dark hours in the summer.

Overall

By Month

Individual Forecasts

The length of each colored bar in the "occurrence of each Forecast" column is proportional to the number of times the chart forecast that color. The percentages are of the total number of hours per month, or per year, with a particular forecast. The colors as the same as those used in clear sky charts.

Note: Transparency probabilities are only counted for those hours that have 30% or less cloud cover. Seeing probabilities are only counted for those hours that have 80% or less cloud cover. If that's too tricky, try Observing Conditions instead.

Overall

		Occurrence of each Forecast	Data Points
Cloud Cover	Day	11% 6% 2 6% 4 4 5% 4 6% 8% 43%	100972
	Night	12% 6% 2 6% 4 4 4 4 6% 8% 42%	99070
Transparency	Day	21% 49% 8% 11% 8% 3	104615
	Night	21% 48% 7% 11% 9% 3	103566
Seeing	Day	13% 8% 24% 28% 20% 6%	15668
	Night	14% 8% 24% 31% 20% 4	25741

By Month

Percentage Cloud Cover SE (2006-)
Color Meanings: Overcast 90% covered 80% covered 70% covered 60% covered 50% covered 40% covered 30% covered 20% covered 10% covered Clear
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	13% 6% 2 5% 3 3 3 3 5% 6% 51%	2836
	11th to 20th	Day	11% 5% 2 5% 3 4 4 3 5% 7% 49%	2840
	21st to end	Day	14% 8% 3 8% 4 4 4 2 5% 7% 41%	3124
February	1st to 10th	Day	15% 5% 2 6% 5% 4 4 4 5% 7% 42%	1710
	11th to 20th	Day	19% 6% 3 5% 4 3 4 3 4 4 45%	1815
	21st to end	Day	14% 7% 2 7% 4 3 4 3 6% 7% 42%	1594
March	1st to 10th	Day	22% 8% 3 7% 4 3 3 3 5% 6% 36%	3435
	11th to 20th	Day	9% 4 2 4 3 3 4 3 5% 7% 55%	3480
	21st to end	Day	15% 6% 2 6% 3 3 3 4 4 5% 48%	3840
April	1st to 10th	Day	11% 4 2 5% 4 3 4 4 5% 6% 53%	2280
	11th to 20th	Day	8% 4 2 5% 3 4 4 4 6% 7% 53%	2254
	21st to end	Day	9% 4 1 5% 4 3 3 3 5% 9% 54%	2280
May	1st to 10th	Day	6% 4 3 6% 5% 5% 5% 5% 8% 10% 42%	3765
	11th to 20th	Day	14% 7% 3 7% 5% 5% 5% 5% 7% 8% 35%	4002
	21st to end	Day	6% 4 1 6% 4 5% 6% 5% 8% 11% 45%	4476
June	1st to 10th	Day	9% 6% 2 7% 6% 5% 5% 5% 8% 10% 37%	2655
	11th to 20th	Day	9% 4 2 4 3 4 5% 5% 9% 12% 43%	2660
	21st to end	Day	7% 5% 2 6% 5% 7% 6% 6% 9% 11% 36%	2534
July	1st to 10th	Day	8% 6% 2 6% 4 5% 5% 4 9% 13% 38%	4120
	11th to 20th	Day	7% 7% 3 8% 6% 6% 7% 5% 8% 12% 32%	4120
	21st to end	Day	7% 7% 3 9% 6% 6% 6% 6% 9% 12% 30%	4466
August	1st to 10th	Day	18% 12% 4 9% 5% 4 4 4 7% 10% 23%	4047
	11th to 20th	Day	7% 5% 2 6% 4 6% 7% 6% 7% 11% 40%	3730
	21st to end	Day	6% 6% 2 6% 5% 4 5% 4 7% 10% 44%	4180
September	1st to 10th	Day	9% 7% 3 5% 4 5% 5% 4 7% 10% 41%	2280
	11th to 20th	Day	14% 7% 3 7% 4 4 5% 3 6% 8% 38%	2280
	21st to end	Day	16% 6% 3 7% 4 4 5% 3 5% 7% 40%	2002
October	1st to 10th	Day	14% 5% 3 6% 4 3 4 3 6% 6% 45%	1900
	11th to 20th	Day	9% 4 2 5% 3 4 3 3 4 7% 57%	1900
	21st to end	Day	10% 5% 2 4 4 3 3 3 4 6% 55%	2090
November	1st to 10th	Day	13% 4 2 4 3 3 4 3 5% 6% 52%	1957
	11th to 20th	Day	11% 6% 3 6% 4 3 4 3 4 5% 51%	1905
	21st to end	Day	10% 5% 2 5% 5% 4 4 3 5% 8% 49%	1796
December	1st to 10th	Day	14% 7% 2 7% 4 4 4 4 6% 7% 40%	1600
	11th to 20th	Day	14% 6% 2 5% 3 3 3 3 3 5% 52%	1990
	21st to end	Day	12% 9% 3 6% 4 4 4 2 4 6% 45%	3029
January	1st to 10th	Night	13% 6% 2 6% 4 3 3 3 5% 7% 47%	4109
	11th to 20th	Night	13% 7% 3 6% 4 4 4 5% 7% 8% 40%	4120
	21st to end	Night	13% 8% 3 7% 4 4 3 4 4 6% 43%	4532
February	1st to 10th	Night	18% 6% 2 5% 4 4 4 3 5% 6% 44%	2470
	11th to 20th	Night	17% 8% 2 6% 4 4 3 3 5% 5% 41%	2249
	21st to end	Night	15% 7% 4 5% 4 4 4 4 5% 7% 41%	1856
March	1st to 10th	Night	22% 10% 3 7% 5% 4 4 3 5% 5% 32%	3418
	11th to 20th	Night	12% 6% 2 5% 4 4 4 3 5% 7% 48%	3480
	21st to end	Night	15% 5% 2 5% 3 3 4 3 5% 7% 49%	3791
April	1st to 10th	Night	10% 6% 2 5% 4 4 4 3 5% 7% 50%	1900
	11th to 20th	Night	9% 6% 3 6% 4 4 4 3 5% 6% 50%	1875
	21st to end	Night	8% 3 1 4 3 3 4 4 6% 8% 55%	1900
May	1st to 10th	Night	7% 6% 2 6% 5% 5% 6% 5% 8% 9% 42%	3130
	11th to 20th	Night	13% 6% 3 8% 5% 5% 5% 4 6% 8% 37%	2919
	21st to end	Night	7% 5% 2 6% 4 4 4 5% 8% 10% 45%	3079
June	1st to 10th	Night	10% 7% 2 6% 6% 6% 5% 4 7% 9% 38%	1520
	11th to 20th	Night	8% 6% 2 5% 4 4 4 5% 8% 12% 43%	1520
	21st to end	Night	8% 6% 2 7% 4 5% 6% 5% 8% 12% 35%	1637
July	1st to 10th	Night	6% 5% 3 7% 6% 5% 7% 5% 9% 13% 35%	2840
	11th to 20th	Night	7% 5% 2 8% 6% 6% 7% 6% 10% 13% 28%	2840
	21st to end	Night	8% 6% 3 7% 6% 6% 7% 6% 10% 12% 28%	3087
August	1st to 10th	Night	14% 11% 5% 9% 5% 5% 5% 5% 8% 11% 24%	2851
	11th to 20th	Night	7% 4 2 8% 5% 6% 6% 6% 8% 12% 36%	3097
	21st to end	Night	7% 5% 2 6% 4 5% 5% 5% 7% 10% 43%	3476
September	1st to 10th	Night	11% 5% 2 5% 5% 5% 5% 6% 7% 10% 40%	1900
	11th to 20th	Night	12% 7% 2 7% 6% 5% 5% 4 6% 8% 38%	1900
	21st to end	Night	15% 8% 3 8% 4 4 4 4 6% 7% 36%	2171
October	1st to 10th	Night	11% 8% 3 6% 4 4 4 3 5% 6% 46%	2280
	11th to 20th	Night	10% 5% 2 6% 4 3 3 3 5% 6% 53%	2280
	21st to end	Night	9% 5% 2 5% 4 3 3 3 5% 6% 56%	2508
November	1st to 10th	Night	12% 6% 2 6% 4 3 4 4 4 6% 49%	2341
	11th to 20th	Night	12% 7% 3 6% 4 4 3 2 5% 6% 48%	2490
	21st to end	Night	11% 6% 2 4 4 4 4 4 4 8% 50%	2600
December	1st to 10th	Night	14% 8% 2 5% 4 4 4 4 5% 7% 44%	2800
	11th to 20th	Night	14% 7% 2 6% 4 4 4 3 4 5% 47%	3425
	21st to end	Night	14% 6% 3 6% 4 3 4 3 4 6% 47%	4679

Transparency (when cloud cover <= 30%)
Color Meanings: Too cloudy to forecast Poor Below Average Average Above average Transparent
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	22% 38% 4 14% 19% 4	2837
	11th to 20th	Day	21% 37% 4 12% 17% 8%	2840
	21st to end	Day	25% 44% 5% 9% 10% 7%	3124
February	1st to 10th	Day	16% 65% 4 8% 6% 1	1710
	11th to 20th	Day	17% 64% 4 6% 7% 2	1824
	21st to end	Day	15% 66% 4 5% 5% 4	1594
March	1st to 10th	Day	38% 42% 6% 6% 4 5%	3435
	11th to 20th	Day	14% 42% 5% 9% 19% 11%	3480
	21st to end	Day	22% 40% 4 19% 11% 5%	3840
April	1st to 10th	Day	13% 65% 5% 7% 7% 2	2280
	11th to 20th	Day	13% 66% 4 8% 5% 3	2254
	21st to end	Day	9% 66% 6% 11% 7% 1	2280
May	1st to 10th	Day	22% 47% 14% 11% 5% 1	3800
	11th to 20th	Day	29% 43% 7% 13% 8%	4006
	21st to end	Day	15% 46% 12% 18% 9% 1	4489
June	1st to 10th	Day	14% 68% 6% 6% 5% 1	2655
	11th to 20th	Day	8% 69% 8% 10% 5%	2660
	21st to end	Day	13% 67% 9% 8% 2	2534
July	1st to 10th	Day	22% 42% 20% 14% 1	4055
	11th to 20th	Day	30% 44% 19% 6% 1	4051
	21st to end	Day	33% 42% 11% 9% 5%	4324
August	1st to 10th	Day	44% 40% 11% 4 1	4034
	11th to 20th	Day	22% 43% 11% 16% 7%	3766
	21st to end	Day	17% 40% 14% 24% 5%	4180
September	1st to 10th	Day	15% 64% 9% 6% 4 1	2280
	11th to 20th	Day	21% 62% 4 6% 4 2	2280
	21st to end	Day	21% 62% 7% 7% 4	2002
October	1st to 10th	Day	24% 38% 5% 15% 14% 4	3160
	11th to 20th	Day	9% 37% 4 12% 16% 22%	3140
	21st to end	Day	15% 37% 4 19% 18% 8%	3428
November	1st to 10th	Day	17% 57% 4 10% 9% 2	1957
	11th to 20th	Day	17% 57% 3 7% 11% 4	1905
	21st to end	Day	14% 57% 4 10% 12% 3	1796
December	1st to 10th	Day	21% 58% 5% 8% 7% 2	1600
	11th to 20th	Day	17% 46% 2 11% 17% 7%	1986
	21st to end	Day	28% 38% 7% 13% 14% 1	3029
January	1st to 10th	Night	24% 38% 6% 15% 14% 4	4109
	11th to 20th	Night	26% 39% 6% 10% 16% 4	4120
	21st to end	Night	26% 43% 4 8% 14% 6%	4532
February	1st to 10th	Night	14% 66% 4 8% 6% 2	2470
	11th to 20th	Night	19% 64% 3 6% 6% 2	2251
	21st to end	Night	17% 65% 2 6% 7% 2	1856
March	1st to 10th	Night	41% 44% 5% 5% 4 1	3418
	11th to 20th	Night	19% 41% 5% 6% 16% 12%	3480
	21st to end	Night	21% 41% 6% 17% 11% 4	3791
April	1st to 10th	Night	12% 66% 5% 7% 8% 2	1900
	11th to 20th	Night	15% 66% 5% 7% 5% 2	1875
	21st to end	Night	9% 67% 5% 14% 5% 1	1900
May	1st to 10th	Night	23% 46% 12% 13% 4 1	3160
	11th to 20th	Night	28% 43% 7% 15% 7%	2920
	21st to end	Night	17% 45% 14% 16% 9%	3087
June	1st to 10th	Night	14% 67% 7% 6% 5% 1	1520
	11th to 20th	Night	8% 68% 7% 12% 5%	1520
	21st to end	Night	13% 66% 8% 10% 3	1637
July	1st to 10th	Night	24% 42% 19% 15%	2795
	11th to 20th	Night	31% 43% 20% 5% 1	2786
	21st to end	Night	31% 45% 9% 8% 6%	2988
August	1st to 10th	Night	40% 42% 12% 5%	2840
	11th to 20th	Night	23% 44% 13% 15% 6%	3127
	21st to end	Night	18% 41% 12% 24% 5%	3476
September	1st to 10th	Night	15% 63% 10% 7% 3 1	1900
	11th to 20th	Night	19% 62% 5% 8% 4 2	1900
	21st to end	Night	20% 62% 8% 7% 3	2171
October	1st to 10th	Night	26% 38% 5% 11% 17% 3	3800
	11th to 20th	Night	9% 36% 3 10% 13% 29%	3779
	21st to end	Night	12% 37% 5% 21% 20% 6%	4120
November	1st to 10th	Night	19% 57% 5% 8% 9% 2	2341
	11th to 20th	Night	18% 57% 3 6% 11% 4	2490
	21st to end	Night	13% 58% 4 12% 11% 3	2600
December	1st to 10th	Night	20% 59% 4 7% 8% 2	2800
	11th to 20th	Night	20% 46% 4 9% 16% 5%	3428
	21st to end	Night	26% 37% 5% 15% 16% 1	4679

Seeing (when cloud cover <= 80%)
Color Meanings: Too cloudy to forecast Bad 1/5 Poor 2/5 Average 3/5 Good 4/5 Excellent 5/5
Month	Days in Month		Occurrence of each Forecast	Data Points
January	1st to 10th	Day	18% 19% 42% 17% 4	270
	11th to 20th	Day	11% 19% 38% 26% 5%	270
	21st to end	Day	18% 19% 35% 23% 5% 1	297
February	1st to 10th	Day	19% 13% 37% 26% 5%	270
	11th to 20th	Day	27% 15% 37% 17% 4	423
	21st to end	Day	16% 17% 40% 20% 6% 1	382
March	1st to 10th	Day	14% 17% 37% 23% 8%	460
	11th to 20th	Day	16% 19% 36% 22% 7% 1	460
	21st to end	Day	16% 13% 38% 23% 9% 2	506
April	1st to 10th	Day	15% 17% 34% 23% 10% 2	460
	11th to 20th	Day	11% 12% 30% 28% 16% 3	452
	21st to end	Day	9% 10% 32% 29% 17% 3	460
May	1st to 10th	Day	8% 14% 30% 28% 15% 4	463
	11th to 20th	Day	14% 5% 23% 34% 18% 6%	487
	21st to end	Day	10% 4 18% 29% 28% 11%	529
June	1st to 10th	Day	9% 3 21% 39% 23% 5%	490
	11th to 20th	Day	10% 3 16% 30% 29% 12%	490
	21st to end	Day	7% 3 14% 35% 30% 10%	490
July	1st to 10th	Day	10% 2 10% 27% 38% 13%	485
	11th to 20th	Day	9% 1 9% 30% 38% 13%	484
	21st to end	Day	10% 1 14% 31% 37% 7%	532
August	1st to 10th	Day	15% 3 13% 26% 31% 11%	486
	11th to 20th	Day	11% 2 9% 28% 35% 15%	479
	21st to end	Day	9% 3 11% 29% 32% 16%	539
September	1st to 10th	Day	10% 2 14% 29% 32% 12%	490
	11th to 20th	Day	17% 4 16% 29% 27% 8%	490
	21st to end	Day	17% 4 17% 28% 24% 9%	490
October	1st to 10th	Day	17% 6% 19% 28% 22% 8%	490
	11th to 20th	Day	10% 3 25% 35% 20% 6%	490
	21st to end	Day	10% 9% 22% 30% 23% 7%	539
November	1st to 10th	Day	16% 8% 26% 28% 18% 4	495
	11th to 20th	Day	13% 11% 35% 29% 10% 1	453
	21st to end	Day	11% 12% 31% 26% 18% 3	396
December	1st to 10th	Day	15% 9% 43% 25% 9%	200
	11th to 20th	Day	19% 12% 31% 25% 13% 1	200
	21st to end	Day	18% 13% 33% 22% 13% 1	271
January	1st to 10th	Night	16% 18% 33% 26% 7% 1	760
	11th to 20th	Night	15% 15% 28% 33% 9%	760
	21st to end	Night	16% 16% 36% 29% 3	836
February	1st to 10th	Night	20% 10% 36% 28% 6%	760
	11th to 20th	Night	22% 15% 35% 25% 4	743
	21st to end	Night	19% 13% 33% 27% 8%	628
March	1st to 10th	Night	17% 11% 36% 28% 7%	760
	11th to 20th	Night	16% 11% 34% 29% 9% 1	760
	21st to end	Night	15% 11% 35% 28% 10% 1	836
April	1st to 10th	Night	14% 11% 34% 30% 11% 1	760
	11th to 20th	Night	11% 10% 29% 32% 16% 2	751
	21st to end	Night	10% 7% 29% 39% 15% 1	760
May	1st to 10th	Night	10% 9% 29% 36% 14% 2	760
	11th to 20th	Night	14% 4 23% 37% 19% 2	629
	21st to end	Night	9% 3 12% 33% 33% 10%	617
June	1st to 10th	Night	13% 2 14% 43% 23% 4	380
	11th to 20th	Night	9% 2 12% 35% 34% 7%	380
	21st to end	Night	11% 2 12% 36% 33% 5%	497
July	1st to 10th	Night	7% 2 10% 32% 41% 8%	555
	11th to 20th	Night	7% 1 8% 31% 45% 9%	552
	21st to end	Night	7% 9% 41% 36% 7%	624
August	1st to 10th	Night	11% 1 11% 28% 40% 8%	580
	11th to 20th	Night	10% 1 11% 33% 35% 10%	750
	21st to end	Night	13% 2 9% 27% 38% 12%	836
September	1st to 10th	Night	12% 1 11% 27% 37% 12%	760
	11th to 20th	Night	16% 2 14% 32% 29% 7%	760
	21st to end	Night	20% 4 15% 27% 29% 6%	760
October	1st to 10th	Night	15% 4 19% 29% 27% 7%	760
	11th to 20th	Night	12% 6% 24% 34% 21% 4	760
	21st to end	Night	12% 7% 23% 31% 22% 5%	836
November	1st to 10th	Night	14% 7% 24% 34% 17% 3	780
	11th to 20th	Night	15% 10% 31% 28% 15% 2	800
	21st to end	Night	14% 10% 29% 29% 17% 2	800
December	1st to 10th	Night	17% 14% 29% 30% 10% 1	800
	11th to 20th	Night	16% 11% 29% 30% 12% 1	800
	21st to end	Night	18% 12% 31% 29% 10%	851

Page generated at 2024-12-21 04:13:50. Version ac07

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