Deep Creek Lake State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Deep Creek Lake State Park clear sky chart from 2005-11-06 to 2024-11-04.

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	13% 10% 4 9% 6% 5% 5% 4 6% 7% 31%	101085
	Night	12% 10% 4 10% 6% 5% 5% 4 5% 6% 33%	97873
Transparency	Day	47% 9% 11% 20% 11% 2	104734
	Night	47% 10% 11% 20% 11% 2	102363
Seeing	Day	25% 19% 27% 17% 9% 3	14840
	Night	23% 19% 24% 23% 10% 1	24526

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	15% 11% 10% 15% 5% 5% 4 3 5% 6% 22%	2836
	11th to 20th	Day	10% 15% 7% 22% 7% 8% 3 3 4 4 18%	2840
	21st to end	Day	14% 15% 6% 17% 8% 5% 5% 3 5% 6% 17%	3124
February	1st to 10th	Day	11% 14% 6% 11% 8% 5% 4 5% 6% 6% 24%	1710
	11th to 20th	Day	14% 9% 4 14% 7% 5% 6% 4 6% 7% 23%	1663
	21st to end	Day	13% 13% 6% 13% 7% 6% 5% 4 4 4 26%	1595
March	1st to 10th	Day	16% 9% 6% 9% 6% 5% 5% 4 5% 7% 27%	3435
	11th to 20th	Day	10% 9% 4 10% 5% 4 5% 4 6% 8% 35%	3480
	21st to end	Day	15% 12% 4 9% 5% 5% 4 3 5% 6% 32%	3815
April	1st to 10th	Day	12% 12% 5% 9% 5% 5% 5% 4 6% 8% 29%	2217
	11th to 20th	Day	14% 11% 4 7% 5% 5% 4 4 5% 6% 36%	2254
	21st to end	Day	18% 10% 3 7% 6% 4 4 3 6% 6% 31%	2418
May	1st to 10th	Day	22% 11% 3 8% 5% 5% 5% 4 6% 6% 25%	4082
	11th to 20th	Day	22% 9% 3 7% 5% 4 5% 4 6% 7% 27%	4081
	21st to end	Day	11% 8% 3 7% 6% 5% 6% 5% 7% 9% 34%	4747
June	1st to 10th	Day	12% 8% 3 7% 5% 6% 5% 5% 8% 8% 34%	2660
	11th to 20th	Day	13% 7% 3 8% 6% 5% 7% 5% 7% 9% 31%	2660
	21st to end	Day	10% 7% 3 7% 6% 6% 6% 5% 7% 9% 34%	2660
July	1st to 10th	Day	8% 6% 3 8% 5% 6% 5% 4 6% 9% 40%	4293
	11th to 20th	Day	9% 7% 2 8% 5% 6% 6% 5% 7% 9% 36%	4120
	21st to end	Day	13% 9% 4 9% 6% 5% 5% 4 6% 7% 31%	4466
August	1st to 10th	Day	13% 7% 3 8% 6% 7% 7% 5% 7% 8% 29%	4104
	11th to 20th	Day	10% 7% 3 8% 6% 6% 6% 5% 7% 9% 33%	4044
	21st to end	Day	8% 5% 2 6% 5% 5% 6% 5% 7% 9% 42%	4221
September	1st to 10th	Day	14% 6% 3 7% 6% 5% 4 3 5% 6% 42%	2280
	11th to 20th	Day	12% 7% 3 7% 5% 4 4 4 6% 7% 41%	2146
	21st to end	Day	18% 11% 3 8% 5% 4 4 4 5% 7% 33%	2057
October	1st to 10th	Day	13% 9% 2 6% 5% 5% 4 3 5% 7% 40%	1900
	11th to 20th	Day	14% 13% 3 7% 4 4 4 3 5% 4 37%	1900
	21st to end	Day	14% 12% 2 8% 5% 5% 4 3 4 6% 37%	2090
November	1st to 10th	Day	10% 9% 4 6% 4 4 5% 3 5% 6% 45%	1887
	11th to 20th	Day	11% 12% 4 11% 6% 4 5% 4 6% 6% 31%	1578
	21st to end	Day	14% 13% 6% 9% 6% 5% 4 3 5% 6% 28%	1520
December	1st to 10th	Day	15% 14% 6% 15% 6% 5% 5% 4 5% 5% 20%	1520
	11th to 20th	Day	13% 14% 6% 14% 6% 5% 5% 3 4 5% 25%	1910
	21st to end	Day	15% 12% 9% 12% 6% 5% 5% 4 7% 6% 19%	2772
January	1st to 10th	Night	8% 12% 9% 21% 6% 6% 5% 4 5% 5% 20%	4109
	11th to 20th	Night	11% 11% 8% 17% 10% 6% 5% 4 4 5% 20%	4120
	21st to end	Night	17% 14% 6% 14% 9% 5% 5% 3 4 4 19%	4532
February	1st to 10th	Night	10% 9% 4 12% 7% 7% 5% 4 7% 6% 29%	2470
	11th to 20th	Night	13% 10% 5% 13% 8% 6% 6% 5% 5% 6% 24%	2403
	21st to end	Night	13% 12% 6% 11% 7% 5% 5% 4 5% 6% 27%	1853
March	1st to 10th	Night	18% 12% 5% 8% 5% 5% 5% 4 5% 6% 28%	3418
	11th to 20th	Night	9% 10% 5% 12% 4 4 5% 3 5% 8% 34%	3480
	21st to end	Night	12% 10% 4 7% 5% 4 4 3 5% 5% 41%	3817
April	1st to 10th	Night	12% 11% 5% 9% 6% 5% 4 4 4 6% 33%	1962
	11th to 20th	Night	11% 9% 3 9% 5% 5% 5% 4 5% 7% 37%	1875
	21st to end	Night	14% 9% 3 8% 5% 5% 4 3 4 6% 38%	1777
May	1st to 10th	Night	25% 11% 3 7% 5% 4 4 3 5% 7% 25%	2813
	11th to 20th	Night	22% 12% 3 7% 4 4 4 3 4 6% 32%	2812
	21st to end	Night	10% 10% 2 7% 5% 5% 5% 5% 7% 8% 37%	2805
June	1st to 10th	Night	9% 8% 3 5% 5% 6% 5% 4 6% 8% 41%	1520
	11th to 20th	Night	10% 6% 2 8% 6% 5% 4 5% 7% 9% 37%	1520
	21st to end	Night	9% 6% 3 7% 5% 5% 5% 4 8% 12% 38%	1520
July	1st to 10th	Night	7% 7% 3 6% 5% 5% 6% 5% 7% 10% 39%	2662
	11th to 20th	Night	7% 7% 3 8% 6% 5% 5% 4 6% 8% 42%	2840
	21st to end	Night	11% 8% 3 7% 7% 4 5% 5% 6% 7% 37%	3087
August	1st to 10th	Night	15% 6% 2 6% 6% 5% 5% 4 7% 10% 33%	2825
	11th to 20th	Night	10% 9% 3 6% 6% 5% 4 4 5% 7% 40%	2785
	21st to end	Night	7% 6% 2 6% 5% 5% 4 4 6% 8% 48%	3402
September	1st to 10th	Night	12% 7% 2 6% 5% 4 4 4 5% 7% 45%	1900
	11th to 20th	Night	10% 7% 2 7% 4 3 3 3 5% 7% 48%	2030
	21st to end	Night	17% 9% 3 6% 4 4 4 3 5% 6% 37%	2122
October	1st to 10th	Night	14% 8% 2 6% 4 5% 5% 3 4 6% 43%	2280
	11th to 20th	Night	11% 10% 2 7% 4 4 5% 4 6% 7% 41%	2280
	21st to end	Night	15% 11% 3 6% 5% 5% 3 3 4 6% 39%	2508
November	1st to 10th	Night	8% 11% 3 7% 5% 4 4 3 4 6% 44%	2264
	11th to 20th	Night	12% 11% 5% 8% 7% 5% 5% 4 5% 6% 32%	2597
	21st to end	Night	12% 11% 5% 10% 6% 5% 6% 4 5% 6% 29%	2660
December	1st to 10th	Night	15% 13% 6% 15% 6% 6% 6% 3 5% 4 22%	2660
	11th to 20th	Night	14% 9% 5% 14% 7% 7% 6% 4 5% 6% 24%	3285
	21st to end	Night	14% 13% 8% 13% 6% 6% 5% 5% 5% 6% 19%	4880

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	56% 12% 11% 14% 7% 1	2837
	11th to 20th	Day	67% 9% 7% 10% 6% 1	2840
	21st to end	Day	62% 11% 9% 13% 5% 1	3124
February	1st to 10th	Day	56% 10% 10% 15% 9%	1710
	11th to 20th	Day	57% 9% 11% 13% 10%	1672
	21st to end	Day	57% 9% 8% 14% 9% 2	1595
March	1st to 10th	Day	52% 8% 12% 20% 8% 1	3435
	11th to 20th	Day	41% 12% 11% 26% 10% 1	3480
	21st to end	Day	50% 8% 11% 19% 12% 1	3815
April	1st to 10th	Day	50% 9% 11% 16% 12% 3	2217
	11th to 20th	Day	46% 8% 11% 16% 16% 3	2254
	21st to end	Day	50% 8% 11% 21% 9% 1	2418
May	1st to 10th	Day	57% 9% 8% 19% 7% 1	4120
	11th to 20th	Day	52% 10% 11% 21% 5% 1	4085
	21st to end	Day	39% 13% 15% 20% 10% 2	4761
June	1st to 10th	Day	43% 11% 11% 22% 12% 1	2660
	11th to 20th	Day	45% 11% 12% 22% 9% 1	2660
	21st to end	Day	42% 12% 13% 23% 10% 1	2660
July	1st to 10th	Day	39% 9% 12% 25% 11% 3	4227
	11th to 20th	Day	41% 9% 13% 26% 10% 1	4051
	21st to end	Day	48% 8% 8% 21% 13% 1	4324
August	1st to 10th	Day	48% 11% 14% 21% 7%	4091
	11th to 20th	Day	43% 8% 11% 28% 10%	4083
	21st to end	Day	34% 10% 14% 27% 14% 1	4221
September	1st to 10th	Day	42% 8% 10% 18% 18% 3	2280
	11th to 20th	Day	40% 7% 11% 25% 15% 2	2146
	21st to end	Day	49% 7% 11% 19% 14% 1	2057
October	1st to 10th	Day	33% 6% 8% 26% 22% 6%	3160
	11th to 20th	Day	38% 5% 12% 21% 14% 10%	3140
	21st to end	Day	31% 5% 10% 29% 22% 2	3428
November	1st to 10th	Day	38% 8% 9% 22% 17% 5%	1887
	11th to 20th	Day	49% 9% 9% 15% 14% 3	1578
	21st to end	Day	55% 8% 11% 16% 10% 1	1520
December	1st to 10th	Day	64% 9% 9% 12% 5% 1	1520
	11th to 20th	Day	57% 9% 9% 19% 5% 1	1906
	21st to end	Day	58% 11% 13% 10% 7%	2772
January	1st to 10th	Night	60% 12% 8% 12% 7% 1	4109
	11th to 20th	Night	59% 11% 15% 11% 3	4120
	21st to end	Night	61% 12% 9% 12% 5% 1	4532
February	1st to 10th	Night	51% 12% 10% 17% 10% 1	2470
	11th to 20th	Night	58% 9% 10% 14% 9%	2405
	21st to end	Night	54% 10% 9% 16% 9% 3	1853
March	1st to 10th	Night	51% 10% 11% 20% 8% 1	3418
	11th to 20th	Night	44% 12% 11% 26% 6% 1	3480
	21st to end	Night	41% 9% 10% 24% 14% 2	3817
April	1st to 10th	Night	51% 8% 9% 17% 13% 2	1962
	11th to 20th	Night	44% 9% 12% 18% 14% 3	1875
	21st to end	Night	45% 7% 11% 24% 10% 3	1777
May	1st to 10th	Night	57% 9% 8% 17% 8% 2	2840
	11th to 20th	Night	50% 11% 9% 21% 8% 1	2813
	21st to end	Night	37% 16% 14% 21% 8% 4	2812
June	1st to 10th	Night	39% 11% 11% 25% 13% 1	1520
	11th to 20th	Night	40% 10% 13% 24% 10% 1	1520
	21st to end	Night	36% 11% 16% 23% 14% 1	1520
July	1st to 10th	Night	38% 10% 14% 24% 11% 3	2618
	11th to 20th	Night	38% 9% 15% 27% 11% 1	2786
	21st to end	Night	43% 10% 11% 21% 15% 1	2988
August	1st to 10th	Night	43% 10% 18% 22% 7% 1	2814
	11th to 20th	Night	42% 7% 11% 25% 14%	2812
	21st to end	Night	33% 8% 14% 33% 11% 1	3402
September	1st to 10th	Night	37% 9% 12% 21% 17% 3	1900
	11th to 20th	Night	33% 8% 11% 27% 18% 2	2030
	21st to end	Night	45% 7% 12% 20% 16%	2122
October	1st to 10th	Night	36% 6% 9% 27% 20% 2	3800
	11th to 20th	Night	34% 7% 9% 22% 18% 9%	3779
	21st to end	Night	33% 6% 8% 28% 20% 5%	4120
November	1st to 10th	Night	40% 8% 10% 20% 17% 6%	2264
	11th to 20th	Night	50% 8% 8% 18% 14% 2	2597
	21st to end	Night	53% 9% 10% 16% 10% 2	2660
December	1st to 10th	Night	61% 10% 9% 14% 4 2	2660
	11th to 20th	Night	56% 10% 10% 15% 8% 1	3288
	21st to end	Night	60% 12% 11% 11% 6%	4880

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	42% 27% 22% 6% 3	270
	11th to 20th	Day	43% 29% 23% 4 1	270
	21st to end	Day	35% 35% 24% 4 2	297
February	1st to 10th	Day	37% 29% 27% 6% 1	270
	11th to 20th	Day	50% 25% 23% 3	270
	21st to end	Day	41% 30% 23% 5% 1	307
March	1st to 10th	Day	34% 27% 26% 10% 2	460
	11th to 20th	Day	38% 27% 22% 10% 3 1	460
	21st to end	Day	34% 25% 26% 12% 2	506
April	1st to 10th	Day	30% 24% 28% 13% 4	460
	11th to 20th	Day	28% 22% 28% 13% 6% 2	452
	21st to end	Day	33% 24% 25% 13% 5% 1	460
May	1st to 10th	Day	33% 19% 28% 13% 5% 3	463
	11th to 20th	Day	27% 21% 26% 17% 7% 3	487
	21st to end	Day	18% 16% 28% 21% 11% 5%	529
June	1st to 10th	Day	17% 19% 29% 21% 11% 4	490
	11th to 20th	Day	19% 16% 28% 21% 12% 4	490
	21st to end	Day	12% 18% 33% 23% 12% 3	490
July	1st to 10th	Day	13% 9% 31% 24% 16% 8%	485
	11th to 20th	Day	8% 11% 34% 27% 13% 6%	484
	21st to end	Day	16% 12% 27% 26% 13% 6%	532
August	1st to 10th	Day	12% 13% 28% 25% 16% 7%	486
	11th to 20th	Day	15% 10% 27% 25% 14% 10%	479
	21st to end	Day	12% 9% 27% 27% 15% 10%	539
September	1st to 10th	Day	16% 11% 24% 24% 16% 8%	490
	11th to 20th	Day	14% 8% 28% 24% 19% 7%	490
	21st to end	Day	28% 14% 25% 18% 11% 3	490
October	1st to 10th	Day	20% 13% 29% 23% 13% 3	490
	11th to 20th	Day	25% 21% 26% 20% 7% 1	490
	21st to end	Day	28% 23% 27% 15% 8%	539
November	1st to 10th	Day	23% 19% 29% 19% 9% 2	467
	11th to 20th	Day	29% 28% 28% 10% 5%	210
	21st to end	Day	35% 28% 26% 8% 2 1	180
December	1st to 10th	Day	39% 30% 21% 7% 2 2	180
	11th to 20th	Day	41% 27% 22% 8% 2	180
	21st to end	Day	37% 27% 22% 11% 3	198
January	1st to 10th	Night	33% 30% 24% 10% 3	760
	11th to 20th	Night	33% 30% 25% 12% 1	760
	21st to end	Night	34% 30% 25% 11% 1	836
February	1st to 10th	Night	31% 25% 28% 15% 1	760
	11th to 20th	Night	35% 34% 24% 7%	743
	21st to end	Night	32% 29% 27% 11% 1	628
March	1st to 10th	Night	29% 25% 27% 17% 2	760
	11th to 20th	Night	34% 23% 24% 14% 5% 1	760
	21st to end	Night	24% 25% 31% 15% 4 1	836
April	1st to 10th	Night	24% 26% 30% 17% 3	760
	11th to 20th	Night	22% 20% 29% 21% 8% 1	751
	21st to end	Night	24% 17% 26% 25% 6%	637
May	1st to 10th	Night	23% 16% 25% 27% 8%	570
	11th to 20th	Night	23% 12% 26% 26% 11% 1	561
	21st to end	Night	9% 11% 25% 29% 23% 2	459
June	1st to 10th	Night	11% 12% 24% 36% 16% 1	380
	11th to 20th	Night	13% 10% 24% 32% 20% 1	380
	21st to end	Night	11% 8% 32% 34% 14% 1	380
July	1st to 10th	Night	9% 9% 23% 35% 21% 4	443
	11th to 20th	Night	7% 8% 21% 36% 24% 4	552
	21st to end	Night	10% 8% 22% 35% 24% 2	624
August	1st to 10th	Night	11% 6% 18% 39% 24% 2	567
	11th to 20th	Night	11% 7% 17% 38% 23% 4	564
	21st to end	Night	11% 6% 19% 37% 23% 3	788
September	1st to 10th	Night	16% 6% 23% 32% 20% 4	760
	11th to 20th	Night	14% 8% 18% 34% 23% 3	760
	21st to end	Night	23% 13% 18% 28% 16% 2	760
October	1st to 10th	Night	19% 13% 23% 25% 18% 2	760
	11th to 20th	Night	21% 17% 27% 25% 9% 1	760
	21st to end	Night	26% 21% 24% 22% 6% 1	836
November	1st to 10th	Night	19% 18% 26% 26% 9% 1	755
	11th to 20th	Night	28% 21% 25% 18% 6% 1	760
	21st to end	Night	28% 22% 28% 18% 4 1	760
December	1st to 10th	Night	33% 24% 23% 14% 5%	760
	11th to 20th	Night	31% 28% 23% 16% 2	760
	21st to end	Night	30% 27% 26% 16% 2	836

Page generated at 2024-11-01 22:47:37. Version ac07

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