Hickory Knolls Discovery Center
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Hickory Knolls Discovery Center clear sky chart from 2005-11-06 to 2026-01-02.

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% 9% 3 8% 5% 4 5% 4 6% 7% 36%	127300
	Night	13% 10% 4 8% 4 4 4 3 5% 6% 38%	124322
Transparency	Day	45% 6% 11% 23% 14% 2	130821
	Night	45% 5% 11% 23% 15% 2	128875
Seeing	Day	16% 14% 30% 24% 12% 4	17380
	Night	17% 11% 31% 28% 11% 1	27274

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	11% 11% 7% 13% 7% 5% 5% 4 6% 6% 26%	3625
	11th to 20th	Day	10% 13% 6% 12% 4 5% 4 6% 6% 4 30%	3620
	21st to end	Day	15% 16% 7% 9% 4 3 3 3 5% 6% 30%	4138
February	1st to 10th	Day	14% 15% 5% 8% 6% 6% 5% 4 5% 7% 26%	1824
	11th to 20th	Day	14% 12% 4 8% 5% 6% 3 3 5% 5% 35%	1948
	21st to end	Day	14% 13% 4 9% 6% 3 4 3 5% 6% 31%	1650
March	1st to 10th	Day	16% 11% 4 7% 4 3 3 3 4 5% 41%	4480
	11th to 20th	Day	9% 7% 3 7% 5% 5% 4 4 5% 8% 43%	4692
	21st to end	Day	19% 14% 6% 13% 6% 5% 5% 3 5% 5% 20%	5967
April	1st to 10th	Day	17% 14% 4 8% 5% 4 5% 3 5% 6% 30%	2400
	11th to 20th	Day	16% 10% 3 6% 5% 4 5% 4 6% 6% 34%	2374
	21st to end	Day	19% 9% 2 7% 5% 4 5% 4 5% 6% 33%	2495
May	1st to 10th	Day	16% 8% 3 6% 4 4 5% 4 6% 8% 35%	5862
	11th to 20th	Day	14% 6% 2 7% 5% 5% 5% 4 6% 7% 40%	6224
	21st to end	Day	13% 7% 2 7% 5% 5% 4 4 7% 9% 37%	6935
June	1st to 10th	Day	10% 5% 3 6% 5% 4 5% 4 6% 8% 46%	2800
	11th to 20th	Day	9% 6% 2 6% 5% 4 5% 3 6% 9% 44%	2800
	21st to end	Day	11% 7% 2 6% 5% 5% 6% 5% 7% 8% 39%	2800
July	1st to 10th	Day	9% 6% 3 7% 5% 6% 6% 5% 7% 9% 35%	6360
	11th to 20th	Day	8% 6% 2 7% 5% 5% 6% 5% 7% 10% 40%	6360
	21st to end	Day	10% 7% 3 7% 6% 5% 5% 4 7% 9% 38%	6924
August	1st to 10th	Day	8% 5% 2 7% 4 4 5% 4 6% 10% 43%	4483
	11th to 20th	Day	10% 5% 2 6% 5% 5% 5% 5% 7% 9% 42%	3849
	21st to end	Day	7% 6% 2 6% 4 4 5% 4 6% 10% 47%	4312
September	1st to 10th	Day	11% 5% 2 5% 4 4 5% 4 5% 7% 47%	2400
	11th to 20th	Day	11% 4 1 4 3 3 4 4 6% 6% 54%	2285
	21st to end	Day	9% 7% 2 6% 4 4 5% 4 5% 7% 45%	2200
October	1st to 10th	Day	11% 6% 2 6% 5% 4 4 3 5% 7% 47%	2127
	11th to 20th	Day	17% 10% 2 6% 4 4 5% 3 6% 7% 36%	2000
	21st to end	Day	18% 9% 3 7% 4 3 4 3 5% 6% 38%	1980
November	1st to 10th	Day	12% 9% 3 7% 4 4 4 3 5% 6% 44%	1852
	11th to 20th	Day	15% 13% 4 9% 4 4 4 3 5% 7% 33%	1890
	21st to end	Day	17% 13% 4 9% 5% 4 3 3 4 5% 34%	1796
December	1st to 10th	Day	8% 10% 4 9% 5% 4 4 3 4 6% 43%	2690
	11th to 20th	Day	12% 15% 4 12% 7% 5% 6% 4 5% 6% 25%	3088
	21st to end	Day	23% 23% 8% 12% 5% 4 4 3 3 4 12%	4070
January	1st to 10th	Night	11% 13% 6% 13% 6% 5% 4 3 4 4 32%	6363
	11th to 20th	Night	13% 15% 6% 13% 6% 5% 4 5% 6% 4 23%	6360
	21st to end	Night	16% 15% 7% 9% 4 4 3 3 4 4 31%	6835
February	1st to 10th	Night	14% 14% 5% 8% 5% 5% 4 3 4 6% 32%	2575
	11th to 20th	Night	13% 12% 3 8% 5% 4 4 4 5% 6% 37%	2338
	21st to end	Night	16% 12% 4 8% 4 4 3 2 5% 5% 37%	1980
March	1st to 10th	Night	16% 10% 4 7% 4 3 4 2 4 5% 42%	5373
	11th to 20th	Night	10% 7% 2 6% 4 4 4 3 5% 7% 48%	5310
	21st to end	Night	19% 11% 5% 11% 6% 5% 4 3 4 6% 28%	4962
April	1st to 10th	Night	16% 9% 2 6% 4 4 4 3 5% 6% 39%	2000
	11th to 20th	Night	17% 10% 2 6% 5% 4 4 3 5% 5% 39%	1975
	21st to end	Night	17% 9% 3 7% 5% 3 4 3 6% 7% 37%	1905
May	1st to 10th	Night	16% 9% 3 7% 5% 4 5% 4 5% 7% 36%	4033
	11th to 20th	Night	12% 6% 2 5% 3 4 4 5% 6% 9% 44%	3684
	21st to end	Night	15% 8% 3 7% 4 4 4 3 5% 7% 40%	3942
June	1st to 10th	Night	9% 5% 2 5% 4 4 4 4 7% 7% 48%	1600
	11th to 20th	Night	9% 5% 2 6% 5% 5% 4 5% 7% 8% 46%	1600
	21st to end	Night	9% 6% 2 6% 5% 4 6% 4 7% 7% 44%	1600
July	1st to 10th	Night	9% 6% 3 7% 5% 6% 5% 5% 6% 9% 40%	3618
	11th to 20th	Night	6% 5% 2 6% 4 4 4 4 6% 9% 50%	3617
	21st to end	Night	8% 6% 2 7% 5% 5% 5% 4 6% 8% 43%	3947
August	1st to 10th	Night	5% 4 2 6% 4 5% 5% 5% 7% 8% 48%	2671
	11th to 20th	Night	7% 5% 2 6% 4 4 4 3 6% 9% 49%	3200
	21st to end	Night	7% 5% 2 4 4 3 4 3 5% 9% 53%	3586
September	1st to 10th	Night	10% 5% 2 5% 3 4 3 3 4 7% 55%	2000
	11th to 20th	Night	9% 3 2 5% 4 3 3 3 5% 8% 55%	2095
	21st to end	Night	10% 6% 2 6% 5% 3 3 4 6% 8% 47%	2200
October	1st to 10th	Night	10% 5% 2 5% 4 3 4 3 5% 6% 52%	2270
	11th to 20th	Night	17% 7% 2 6% 3 4 3 3 4 6% 45%	2400
	21st to end	Night	20% 9% 3 6% 4 4 4 3 4 7% 38%	2859
November	1st to 10th	Night	12% 8% 3 6% 4 3 4 3 4 5% 48%	2666
	11th to 20th	Night	15% 10% 4 7% 4 3 4 3 5% 7% 37%	2730
	21st to end	Night	16% 11% 4 9% 4 4 4 3 5% 5% 36%	2819
December	1st to 10th	Night	11% 9% 3 7% 5% 4 4 3 5% 7% 41%	4720
	11th to 20th	Night	17% 16% 4 8% 5% 4 3 3 4 5% 30%	5339
	21st to end	Night	23% 19% 6% 10% 4 4 4 4 4 5% 17%	7150

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	58% 5% 11% 18% 8%	3626
	11th to 20th	Day	53% 6% 10% 11% 16% 5%	3620
	21st to end	Day	56% 4 12% 18% 9%	4138
February	1st to 10th	Day	58% 6% 11% 14% 9% 2	1824
	11th to 20th	Day	51% 5% 10% 23% 9% 2	1958
	21st to end	Day	54% 5% 11% 19% 9% 2	1650
March	1st to 10th	Day	46% 5% 9% 25% 12% 3	4480
	11th to 20th	Day	39% 5% 11% 32% 11% 1	4692
	21st to end	Day	65% 6% 10% 12% 6% 1	5969
April	1st to 10th	Day	54% 5% 10% 20% 11%	2400
	11th to 20th	Day	48% 6% 9% 22% 12% 3	2374
	21st to end	Day	51% 6% 11% 19% 12% 2	2495
May	1st to 10th	Day	45% 7% 10% 24% 13% 1	5897
	11th to 20th	Day	42% 7% 9% 25% 16% 1	6228
	21st to end	Day	41% 6% 11% 25% 13% 3	6949
June	1st to 10th	Day	35% 7% 12% 28% 17% 2	2800
	11th to 20th	Day	35% 8% 11% 24% 19% 3	2800
	21st to end	Day	40% 8% 13% 23% 14% 3	2800
July	1st to 10th	Day	41% 7% 12% 24% 14% 1	6291
	11th to 20th	Day	36% 6% 14% 27% 16% 1	6285
	21st to end	Day	41% 7% 15% 21% 15% 2	6728
August	1st to 10th	Day	35% 7% 16% 29% 13% 1	4468
	11th to 20th	Day	35% 7% 12% 30% 15% 1	3885
	21st to end	Day	32% 6% 13% 28% 19% 2	4311
September	1st to 10th	Day	35% 6% 11% 26% 18% 4	2400
	11th to 20th	Day	29% 6% 11% 29% 23% 3	2285
	21st to end	Day	36% 7% 8% 27% 20% 1	2200
October	1st to 10th	Day	25% 4 7% 30% 32% 2	3465
	11th to 20th	Day	32% 4 11% 27% 25% 1	3240
	21st to end	Day	42% 4 9% 28% 14% 3	3180
November	1st to 10th	Day	40% 5% 13% 24% 15% 2	1852
	11th to 20th	Day	52% 4 10% 22% 10% 1	1890
	21st to end	Day	54% 4 11% 23% 8%	1796
December	1st to 10th	Day	44% 4 16% 27% 8% 1	2690
	11th to 20th	Day	59% 4 13% 17% 6% 1	3085
	21st to end	Day	78% 4 6% 8% 4	4070
January	1st to 10th	Night	55% 5% 9% 19% 11% 1	6363
	11th to 20th	Night	63% 4 9% 9% 14% 1	6360
	21st to end	Night	57% 4 11% 16% 11% 1	6835
February	1st to 10th	Night	55% 4 11% 17% 12% 1	2575
	11th to 20th	Night	48% 5% 10% 22% 14% 1	2339
	21st to end	Night	49% 5% 12% 19% 11% 3	1980
March	1st to 10th	Night	46% 4 11% 24% 11% 4	5373
	11th to 20th	Night	36% 5% 11% 31% 14% 3	5310
	21st to end	Night	58% 5% 9% 19% 9% 1	4962
April	1st to 10th	Night	45% 5% 12% 23% 13% 2	2000
	11th to 20th	Night	46% 5% 8% 21% 16% 4	1975
	21st to end	Night	46% 7% 11% 22% 12% 3	1905
May	1st to 10th	Night	47% 6% 11% 18% 15% 3	4060
	11th to 20th	Night	34% 9% 14% 25% 14% 4	3685
	21st to end	Night	42% 7% 9% 23% 16% 4	3950
June	1st to 10th	Night	33% 6% 12% 26% 19% 3	1600
	11th to 20th	Night	33% 6% 11% 26% 21% 3	1600
	21st to end	Night	37% 9% 14% 21% 17% 2	1600
July	1st to 10th	Night	40% 6% 13% 24% 14% 3	3580
	11th to 20th	Night	31% 6% 13% 30% 19% 1	3572
	21st to end	Night	36% 7% 14% 22% 18% 3	3832
August	1st to 10th	Night	30% 8% 15% 28% 18% 1	2662
	11th to 20th	Night	30% 7% 14% 30% 18% 1	3230
	21st to end	Night	28% 6% 12% 34% 17% 4	3586
September	1st to 10th	Night	29% 6% 11% 28% 23% 3	2000
	11th to 20th	Night	27% 5% 8% 33% 25% 2	2095
	21st to end	Night	35% 6% 10% 29% 17% 2	2200
October	1st to 10th	Night	22% 4 7% 37% 28% 2	3712
	11th to 20th	Night	35% 4 7% 23% 28% 2	3899
	21st to end	Night	41% 4 8% 26% 18% 3	4609
November	1st to 10th	Night	38% 5% 9% 27% 18% 3	2666
	11th to 20th	Night	48% 4 11% 22% 12% 2	2730
	21st to end	Night	51% 5% 11% 22% 11%	2819
December	1st to 10th	Night	43% 4 14% 27% 10% 2	4720
	11th to 20th	Night	57% 4 12% 16% 10% 1	5341
	21st to end	Night	70% 4 8% 11% 6%	7150

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	20% 17% 38% 21% 3	303
	11th to 20th	Day	20% 21% 40% 15% 3	300
	21st to end	Day	22% 23% 34% 16% 4 1	330
February	1st to 10th	Day	22% 23% 38% 15% 3	300
	11th to 20th	Day	25% 23% 33% 16% 2	300
	21st to end	Day	23% 26% 38% 9% 4	249
March	1st to 10th	Day	21% 28% 36% 15% 1	300
	11th to 20th	Day	28% 20% 33% 15% 3	313
	21st to end	Day	27% 18% 32% 17% 5% 1	550
April	1st to 10th	Day	25% 18% 32% 21% 5%	500
	11th to 20th	Day	23% 24% 23% 20% 9% 2	492
	21st to end	Day	22% 19% 29% 22% 7% 1	500
May	1st to 10th	Day	21% 16% 31% 23% 8% 2	503
	11th to 20th	Day	20% 13% 31% 24% 10% 2	682
	21st to end	Day	16% 12% 32% 22% 14% 4	789
June	1st to 10th	Day	11% 11% 32% 28% 13% 4	730
	11th to 20th	Day	11% 8% 36% 28% 13% 4	730
	21st to end	Day	11% 11% 33% 29% 11% 4	730
July	1st to 10th	Day	8% 4 24% 33% 18% 12%	721
	11th to 20th	Day	9% 8% 27% 33% 15% 8%	718
	21st to end	Day	8% 5% 28% 36% 17% 6%	794
August	1st to 10th	Day	7% 4 23% 36% 21% 9%	691
	11th to 20th	Day	11% 6% 20% 29% 23% 11%	519
	21st to end	Day	7% 5% 19% 35% 25% 9%	583
September	1st to 10th	Day	13% 8% 22% 27% 23% 6%	530
	11th to 20th	Day	9% 4 18% 33% 24% 10%	530
	21st to end	Day	12% 15% 24% 25% 18% 6%	530
October	1st to 10th	Day	14% 10% 26% 30% 16% 4	457
	11th to 20th	Day	20% 22% 32% 19% 6%	330
	21st to end	Day	30% 16% 33% 15% 6%	363
November	1st to 10th	Day	18% 18% 36% 19% 7% 2	330
	11th to 20th	Day	27% 21% 31% 15% 6% 1	330
	21st to end	Day	27% 15% 37% 18% 3	330
December	1st to 10th	Day	15% 24% 41% 14% 6%	330
	11th to 20th	Day	20% 24% 34% 17% 4	330
	21st to end	Day	28% 23% 36% 11% 2	363
January	1st to 10th	Night	18% 15% 41% 21% 4	1006
	11th to 20th	Night	21% 17% 37% 20% 4 1	1000
	21st to end	Night	21% 14% 37% 25% 3	1100
February	1st to 10th	Night	22% 15% 36% 22% 4	975
	11th to 20th	Night	20% 16% 36% 23% 4	783
	21st to end	Night	21% 17% 38% 20% 3	660
March	1st to 10th	Night	20% 16% 36% 22% 6%	800
	11th to 20th	Night	17% 13% 39% 23% 7%	762
	21st to end	Night	23% 12% 33% 25% 6% 1	660
April	1st to 10th	Night	19% 16% 34% 25% 6%	600
	11th to 20th	Night	22% 15% 30% 26% 6%	593
	21st to end	Night	20% 13% 33% 27% 7%	600
May	1st to 10th	Night	17% 9% 37% 30% 7% 1	600
	11th to 20th	Night	17% 8% 30% 31% 13%	591
	21st to end	Night	14% 6% 28% 35% 16%	650
June	1st to 10th	Night	11% 6% 29% 40% 14%	600
	11th to 20th	Night	11% 5% 33% 40% 11% 1	600
	21st to end	Night	11% 5% 30% 37% 17% 1	600
July	1st to 10th	Night	8% 2 19% 42% 26% 3	585
	11th to 20th	Night	7% 3 22% 41% 24% 3	582
	21st to end	Night	6% 2 22% 44% 25% 2	657
August	1st to 10th	Night	5% 3 16% 46% 27% 3	597
	11th to 20th	Night	8% 2 16% 40% 31% 4	594
	21st to end	Night	9% 2 17% 43% 28% 2	660
September	1st to 10th	Night	11% 5% 21% 33% 26% 3	600
	11th to 20th	Night	9% 4 20% 34% 28% 4	695
	21st to end	Night	11% 8% 23% 33% 22% 2	800
October	1st to 10th	Night	12% 7% 27% 35% 17% 2	800
	11th to 20th	Night	20% 14% 29% 27% 9%	800
	21st to end	Night	24% 14% 32% 22% 9%	880
November	1st to 10th	Night	18% 12% 37% 23% 8% 1	820
	11th to 20th	Night	21% 18% 33% 23% 5%	840
	21st to end	Night	21% 15% 36% 23% 5%	929
December	1st to 10th	Night	22% 15% 36% 22% 4	1050
	11th to 20th	Night	23% 14% 35% 24% 4	1050
	21st to end	Night	31% 14% 34% 19% 2	1155

Page generated at 2025-12-30 00:14:11. Version ac07

Copyright © 2025 Attilla Danko.