Kunkle Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Kunkle Park clear sky chart from 2005-11-06 to 2025-07-21.

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	16% 11% 4 9% 5% 5% 4 4 5% 7% 30%	120125
	Night	17% 12% 4 9% 5% 4 4 3 5% 6% 31%	118971
Transparency	Day	52% 6% 11% 20% 10% 1	123769
	Night	53% 5% 10% 19% 10% 2	123464
Seeing	Day	24% 14% 26% 20% 11% 4	15597
	Night	23% 12% 25% 27% 11% 1	25238

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	17% 19% 9% 23% 5% 3 2 2 2 4 15%	3946
	11th to 20th	Day	13% 22% 10% 19% 10% 6% 2 2 2 3 13%	4060
	21st to end	Day	20% 21% 6% 11% 7% 5% 4 3 3 4 16%	4466
February	1st to 10th	Day	20% 17% 6% 12% 6% 4 3 3 3 4 20%	1800
	11th to 20th	Day	18% 16% 6% 14% 5% 4 4 3 6% 5% 20%	1753
	21st to end	Day	20% 16% 4 11% 5% 4 4 2 4 5% 24%	1646
March	1st to 10th	Day	17% 13% 5% 8% 4 4 3 2 4 5% 32%	4935
	11th to 20th	Day	14% 10% 5% 8% 5% 5% 5% 4 4 6% 35%	4980
	21st to end	Day	17% 11% 3 9% 6% 5% 5% 4 5% 6% 30%	5465
April	1st to 10th	Day	17% 13% 3 8% 5% 5% 4 4 6% 6% 29%	2328
	11th to 20th	Day	16% 12% 3 7% 5% 4 4 4 5% 6% 33%	2375
	21st to end	Day	21% 9% 3 8% 4 4 4 3 5% 6% 34%	2600
May	1st to 10th	Day	21% 9% 3 8% 5% 5% 5% 5% 6% 7% 26%	5862
	11th to 20th	Day	19% 8% 3 8% 5% 5% 5% 4 6% 8% 29%	5861
	21st to end	Day	20% 8% 2 6% 4 5% 5% 4 6% 8% 32%	6925
June	1st to 10th	Day	14% 6% 3 7% 5% 6% 6% 5% 6% 8% 34%	2800
	11th to 20th	Day	15% 7% 2 7% 5% 5% 5% 5% 7% 8% 34%	2800
	21st to end	Day	13% 6% 3 7% 6% 5% 5% 4 6% 10% 37%	2800
July	1st to 10th	Day	10% 6% 2 6% 6% 5% 5% 4 7% 8% 40%	4528
	11th to 20th	Day	11% 6% 3 7% 4 5% 5% 4 6% 10% 38%	4250
	21st to end	Day	13% 7% 3 8% 6% 6% 5% 4 6% 7% 36%	4466
August	1st to 10th	Day	16% 9% 3 8% 5% 5% 6% 5% 6% 8% 30%	4104
	11th to 20th	Day	12% 7% 2 6% 5% 6% 6% 4 8% 8% 35%	4044
	21st to end	Day	9% 5% 2 6% 5% 5% 6% 5% 7% 10% 41%	4281
September	1st to 10th	Day	16% 7% 2 5% 4 3 4 3 5% 6% 45%	2280
	11th to 20th	Day	12% 6% 2 6% 5% 4 4 4 5% 8% 44%	2131
	21st to end	Day	20% 8% 3 7% 5% 4 3 4 5% 6% 35%	2067
October	1st to 10th	Day	18% 5% 2 6% 4 4 3 4 6% 8% 39%	1900
	11th to 20th	Day	20% 8% 2 7% 4 5% 5% 3 5% 6% 35%	1900
	21st to end	Day	23% 11% 2 7% 5% 3 3 3 5% 7% 33%	2090
November	1st to 10th	Day	12% 9% 3 7% 6% 4 4 3 4 6% 42%	1906
	11th to 20th	Day	18% 15% 3 7% 4 4 5% 3 5% 6% 31%	1626
	21st to end	Day	19% 17% 5% 8% 4 5% 4 3 4 5% 24%	1600
December	1st to 10th	Day	18% 15% 7% 20% 6% 4 4 2 3 4 17%	2600
	11th to 20th	Day	23% 18% 7% 10% 4 3 3 2 4 5% 21%	2990
	21st to end	Day	22% 22% 6% 11% 5% 4 4 3 4 5% 15%	3960
January	1st to 10th	Night	15% 18% 7% 24% 5% 4 3 3 3 3 16%	5981
	11th to 20th	Night	15% 18% 7% 17% 9% 6% 4 2 3 4 15%	5900
	21st to end	Night	22% 16% 6% 11% 6% 5% 5% 2 3 3 19%	6490
February	1st to 10th	Night	20% 15% 5% 10% 6% 5% 4 3 4 5% 24%	2600
	11th to 20th	Night	19% 15% 5% 12% 5% 4 4 3 4 5% 24%	2533
	21st to end	Night	21% 13% 4 11% 5% 4 4 3 5% 5% 25%	1980
March	1st to 10th	Night	21% 12% 5% 9% 5% 3 3 3 4 5% 31%	4918
	11th to 20th	Night	13% 11% 4 7% 4 3 3 3 4 7% 41%	4980
	21st to end	Night	16% 10% 4 8% 5% 5% 5% 3 4 5% 35%	5467
April	1st to 10th	Night	20% 13% 3 6% 4 5% 3 3 3 5% 34%	2070
	11th to 20th	Night	16% 9% 2 8% 3 4 4 4 6% 6% 37%	1975
	21st to end	Night	16% 10% 3 8% 5% 5% 4 3 5% 8% 36%	1815
May	1st to 10th	Night	27% 11% 4 7% 4 4 4 3 5% 6% 25%	4033
	11th to 20th	Night	19% 9% 3 7% 5% 4 4 3 5% 7% 35%	4032
	21st to end	Night	20% 8% 3 6% 4 4 4 4 6% 8% 33%	3927
June	1st to 10th	Night	12% 6% 2 5% 5% 5% 5% 4 6% 8% 43%	1600
	11th to 20th	Night	11% 7% 3 7% 4 4 5% 5% 7% 8% 41%	1600
	21st to end	Night	12% 6% 2 5% 5% 5% 5% 5% 7% 10% 41%	1600
July	1st to 10th	Night	12% 8% 3 8% 5% 4 5% 3 5% 8% 40%	2633
	11th to 20th	Night	11% 5% 3 6% 5% 4 6% 4 6% 9% 40%	2930
	21st to end	Night	12% 7% 3 8% 6% 4 5% 4 6% 7% 39%	3087
August	1st to 10th	Night	14% 9% 3 7% 4 5% 5% 4 6% 8% 35%	2825
	11th to 20th	Night	14% 7% 3 7% 4 4 4 3 5% 7% 41%	2785
	21st to end	Night	8% 5% 2 6% 5% 4 6% 5% 7% 9% 44%	3343
September	1st to 10th	Night	13% 6% 1 5% 3 3 5% 4 5% 7% 48%	1900
	11th to 20th	Night	9% 5% 2 5% 3 3 4 3 5% 7% 53%	2045
	21st to end	Night	17% 9% 3 6% 4 3 4 3 5% 6% 39%	2112
October	1st to 10th	Night	15% 6% 2 7% 4 4 4 4 5% 7% 43%	2280
	11th to 20th	Night	18% 6% 2 6% 5% 5% 4 3 5% 6% 39%	2280
	21st to end	Night	23% 8% 3 6% 4 3 4 2 4 6% 36%	2508
November	1st to 10th	Night	13% 10% 3 6% 4 3 4 3 5% 6% 44%	2390
	11th to 20th	Night	19% 13% 3 6% 6% 4 4 3 5% 6% 30%	2771
	21st to end	Night	20% 15% 4 6% 4 4 3 4 4 6% 29%	2800
December	1st to 10th	Night	18% 16% 11% 15% 5% 3 3 3 4 5% 18%	4580
	11th to 20th	Night	23% 15% 7% 10% 5% 4 3 3 4 4 23%	5205
	21st to end	Night	22% 18% 6% 10% 5% 5% 4 3 4 5% 17%	6996

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	76% 3 7% 9% 5%	3947
	11th to 20th	Day	80% 2 5% 8% 3 1	4060
	21st to end	Day	73% 3 8% 11% 5%	4466
February	1st to 10th	Day	69% 3 8% 14% 6% 1	1800
	11th to 20th	Day	65% 5% 9% 15% 6%	1762
	21st to end	Day	63% 4 11% 15% 7% 1	1646
March	1st to 10th	Day	53% 4 12% 22% 8% 2	4935
	11th to 20th	Day	49% 6% 12% 24% 8% 2	4980
	21st to end	Day	53% 5% 9% 20% 12% 1	5465
April	1st to 10th	Day	54% 5% 10% 18% 11% 2	2328
	11th to 20th	Day	51% 5% 11% 18% 14% 2	2375
	21st to end	Day	50% 6% 9% 22% 11% 2	2600
May	1st to 10th	Day	54% 8% 11% 16% 8% 3	5897
	11th to 20th	Day	50% 8% 11% 21% 9% 1	5865
	21st to end	Day	47% 8% 14% 20% 9% 2	6940
June	1st to 10th	Day	45% 8% 13% 21% 12% 1	2800
	11th to 20th	Day	45% 8% 15% 20% 12% 1	2800
	21st to end	Day	43% 7% 12% 25% 12% 1	2800
July	1st to 10th	Day	40% 8% 11% 25% 15% 2	4459
	11th to 20th	Day	38% 8% 14% 26% 14%	4181
	21st to end	Day	45% 7% 10% 20% 18% 1	4324
August	1st to 10th	Day	50% 8% 13% 20% 8%	4091
	11th to 20th	Day	42% 8% 12% 27% 10% 1	4083
	21st to end	Day	36% 8% 13% 27% 14% 2	4281
September	1st to 10th	Day	41% 6% 10% 22% 19% 3	2280
	11th to 20th	Day	38% 6% 12% 27% 16% 1	2131
	21st to end	Day	49% 5% 10% 22% 14% 1	2067
October	1st to 10th	Day	34% 5% 11% 30% 19% 1	3160
	11th to 20th	Day	43% 7% 11% 21% 14% 5%	3140
	21st to end	Day	37% 4 11% 29% 18% 1	3428
November	1st to 10th	Day	44% 4 12% 21% 17% 2	1906
	11th to 20th	Day	54% 4 11% 19% 10% 2	1626
	21st to end	Day	62% 5% 11% 16% 5% 1	1600
December	1st to 10th	Day	73% 4 10% 9% 4	2600
	11th to 20th	Day	67% 4 12% 14% 3	2986
	21st to end	Day	73% 3 8% 11% 4	3960
January	1st to 10th	Night	75% 3 7% 11% 4	5981
	11th to 20th	Night	75% 4 8% 10% 2 1	5900
	21st to end	Night	71% 3 8% 11% 5% 1	6490
February	1st to 10th	Night	64% 4 9% 16% 6%	2600
	11th to 20th	Night	63% 4 9% 16% 7%	2535
	21st to end	Night	61% 4 9% 16% 9% 1	1980
March	1st to 10th	Night	56% 4 9% 22% 8%	4918
	11th to 20th	Night	44% 4 13% 27% 8% 3	4980
	21st to end	Night	50% 5% 10% 18% 15% 1	5467
April	1st to 10th	Night	53% 5% 9% 19% 13% 1	2070
	11th to 20th	Night	46% 6% 11% 19% 15% 3	1975
	21st to end	Night	47% 6% 9% 24% 11% 3	1815
May	1st to 10th	Night	59% 6% 9% 14% 9% 3	4060
	11th to 20th	Night	48% 7% 9% 24% 10% 1	4033
	21st to end	Night	47% 7% 13% 22% 9% 3	3934
June	1st to 10th	Night	39% 7% 12% 26% 15% 2	1600
	11th to 20th	Night	40% 7% 15% 24% 14% 1	1600
	21st to end	Night	38% 8% 13% 23% 17% 1	1600
July	1st to 10th	Night	43% 6% 9% 23% 16% 3	2592
	11th to 20th	Night	37% 8% 15% 24% 15% 1	2876
	21st to end	Night	43% 7% 11% 16% 22% 2	2988
August	1st to 10th	Night	47% 8% 12% 22% 10%	2814
	11th to 20th	Night	42% 5% 11% 29% 13% 1	2812
	21st to end	Night	33% 8% 13% 30% 13% 2	3343
September	1st to 10th	Night	34% 6% 11% 24% 20% 4	1900
	11th to 20th	Night	30% 5% 13% 28% 23% 1	2045
	21st to end	Night	45% 5% 11% 22% 16% 2	2112
October	1st to 10th	Night	37% 5% 9% 26% 22% 2	3800
	11th to 20th	Night	37% 5% 11% 25% 15% 8%	3779
	21st to end	Night	37% 3 10% 28% 21% 1	4120
November	1st to 10th	Night	42% 4 11% 22% 17% 4	2390
	11th to 20th	Night	54% 5% 9% 20% 10% 2	2771
	21st to end	Night	57% 4 11% 21% 7% 1	2800
December	1st to 10th	Night	70% 4 11% 12% 3	4580
	11th to 20th	Night	66% 4 13% 14% 3	5208
	21st to end	Night	69% 5% 11% 13% 2	6996

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	33% 27% 23% 11% 4 2	277
	11th to 20th	Day	38% 28% 25% 5% 2 1	300
	21st to end	Day	34% 27% 27% 9% 3	330
February	1st to 10th	Day	35% 25% 32% 6% 2	300
	11th to 20th	Day	41% 27% 26% 6% 1	300
	21st to end	Day	40% 23% 29% 6% 1	304
March	1st to 10th	Day	31% 23% 28% 14% 4	500
	11th to 20th	Day	33% 21% 29% 11% 5% 1	500
	21st to end	Day	33% 20% 26% 16% 4 1	550
April	1st to 10th	Day	31% 21% 25% 17% 6% 1	500
	11th to 20th	Day	26% 22% 28% 13% 8% 3	492
	21st to end	Day	30% 17% 28% 18% 6% 2	500
May	1st to 10th	Day	30% 15% 27% 17% 8% 3	503
	11th to 20th	Day	22% 13% 31% 19% 12% 4	527
	21st to end	Day	22% 6% 28% 25% 13% 6%	573
June	1st to 10th	Day	16% 12% 30% 26% 12% 4	530
	11th to 20th	Day	19% 12% 25% 25% 14% 4	530
	21st to end	Day	14% 9% 28% 30% 15% 3	530
July	1st to 10th	Day	13% 8% 19% 28% 21% 10%	525
	11th to 20th	Day	13% 7% 25% 29% 18% 7%	524
	21st to end	Day	16% 5% 25% 31% 17% 7%	532
August	1st to 10th	Day	13% 7% 22% 29% 20% 10%	486
	11th to 20th	Day	16% 6% 20% 28% 19% 10%	479
	21st to end	Day	12% 6% 24% 24% 23% 10%	539
September	1st to 10th	Day	19% 8% 19% 27% 17% 10%	490
	11th to 20th	Day	15% 3 19% 32% 21% 10%	490
	21st to end	Day	26% 11% 22% 23% 13% 6%	490
October	1st to 10th	Day	20% 9% 26% 22% 19% 4	490
	11th to 20th	Day	25% 15% 27% 22% 10% 2	490
	21st to end	Day	29% 15% 30% 16% 9% 1	539
November	1st to 10th	Day	20% 15% 32% 21% 9% 4	444
	11th to 20th	Day	32% 17% 31% 13% 5% 2	213
	21st to end	Day	30% 21% 39% 9% 2 1	200
December	1st to 10th	Day	36% 29% 20% 11% 4 1	200
	11th to 20th	Day	35% 23% 29% 11% 4	200
	21st to end	Day	35% 22% 28% 12% 3	220
January	1st to 10th	Night	30% 22% 30% 15% 3	800
	11th to 20th	Night	33% 20% 27% 17% 3	800
	21st to end	Night	30% 20% 29% 18% 2	880
February	1st to 10th	Night	30% 17% 28% 22% 2	800
	11th to 20th	Night	32% 20% 32% 16% 1	783
	21st to end	Night	29% 17% 32% 20% 2	660
March	1st to 10th	Night	27% 18% 30% 23% 3	800
	11th to 20th	Night	29% 18% 25% 21% 7% 1	800
	21st to end	Night	25% 17% 32% 21% 4 1	880
April	1st to 10th	Night	29% 17% 28% 21% 5%	800
	11th to 20th	Night	25% 13% 29% 23% 9% 1	791
	21st to end	Night	19% 12% 31% 31% 6%	615
May	1st to 10th	Night	24% 10% 24% 32% 9% 1	600
	11th to 20th	Night	21% 8% 25% 33% 12%	591
	21st to end	Night	12% 4 27% 31% 23% 2	441
June	1st to 10th	Night	11% 6% 24% 42% 16% 1	400
	11th to 20th	Night	13% 7% 22% 38% 18% 2	400
	21st to end	Night	13% 4 28% 35% 19% 2	400
July	1st to 10th	Night	10% 3 19% 43% 22% 4	409
	11th to 20th	Night	11% 3 16% 37% 29% 4	582
	21st to end	Night	12% 3 15% 41% 26% 2	624
August	1st to 10th	Night	9% 5% 12% 43% 29% 2	567
	11th to 20th	Night	13% 4 13% 38% 29% 5%	564
	21st to end	Night	12% 4 16% 35% 28% 5%	755
September	1st to 10th	Night	15% 4 18% 34% 25% 3	760
	11th to 20th	Night	11% 4 16% 37% 28% 4	760
	21st to end	Night	20% 8% 22% 28% 19% 3	760
October	1st to 10th	Night	18% 7% 23% 28% 22% 2	760
	11th to 20th	Night	22% 11% 27% 29% 10% 1	760
	21st to end	Night	28% 12% 25% 26% 8%	836
November	1st to 10th	Night	18% 12% 27% 32% 11% 1	780
	11th to 20th	Night	29% 15% 25% 24% 6% 1	800
	21st to end	Night	30% 14% 30% 20% 6% 1	800
December	1st to 10th	Night	32% 18% 29% 17% 4	800
	11th to 20th	Night	30% 21% 26% 20% 3	800
	21st to end	Night	31% 17% 27% 23% 2	880

Page generated at 2025-07-18 01:10:02. Version ac07

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