Little Black Township
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Little Black Township clear sky chart from 2005-11-06 to 2025-06-10.

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 4 4 5% 7% 36%	119935
	Night	12% 10% 4 9% 5% 4 4 4 5% 6% 36%	118553
Transparency	Day	46% 6% 12% 23% 12% 1	123453
	Night	47% 5% 12% 22% 13% 1	123175
Seeing	Day	16% 10% 30% 26% 13% 4	16796
	Night	17% 9% 32% 30% 11% 1	26754

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	8% 12% 6% 18% 9% 6% 5% 4 4 4 25%	3617
	11th to 20th	Day	7% 13% 7% 14% 5% 6% 7% 7% 8% 6% 19%	3620
	21st to end	Day	8% 15% 7% 15% 5% 5% 4 3 5% 7% 25%	4141
February	1st to 10th	Day	9% 11% 6% 12% 6% 5% 6% 4 6% 7% 30%	1800
	11th to 20th	Day	9% 11% 4 10% 6% 5% 4 5% 6% 6% 33%	1785
	21st to end	Day	11% 13% 5% 11% 7% 5% 5% 3 6% 5% 29%	1650
March	1st to 10th	Day	13% 9% 2 4 4 3 4 3 5% 7% 46%	4480
	11th to 20th	Day	11% 8% 3 8% 5% 5% 5% 4 6% 8% 37%	4929
	21st to end	Day	22% 11% 4 10% 5% 4 4 3 4 5% 29%	5815
April	1st to 10th	Day	16% 13% 4 7% 5% 5% 4 4 6% 7% 31%	2400
	11th to 20th	Day	20% 11% 4 9% 4 4 5% 4 5% 6% 29%	2374
	21st to end	Day	20% 11% 3 7% 6% 5% 5% 4 5% 5% 29%	2495
May	1st to 10th	Day	15% 6% 3 6% 4 3 3 3 4 6% 47%	6319
	11th to 20th	Day	14% 7% 2 7% 4 4 4 4 6% 7% 41%	6319
	21st to end	Day	17% 9% 3 6% 4 5% 4 3 6% 7% 36%	6935
June	1st to 10th	Day	14% 6% 3 6% 5% 4 4 4 6% 8% 41%	2787
	11th to 20th	Day	13% 7% 3 7% 6% 6% 5% 4 6% 7% 36%	2660
	21st to end	Day	11% 6% 3 7% 5% 4 5% 4 6% 10% 38%	2660
July	1st to 10th	Day	14% 4 2 6% 5% 4 6% 5% 8% 9% 38%	4440
	11th to 20th	Day	6% 3 1 5% 3 4 4 4 7% 10% 51%	4440
	21st to end	Day	9% 6% 2 6% 4 5% 5% 4 6% 8% 46%	4813
August	1st to 10th	Day	14% 7% 3 6% 4 4 4 3 6% 7% 42%	4371
	11th to 20th	Day	14% 5% 1 6% 3 4 4 4 5% 8% 46%	3981
	21st to end	Day	13% 7% 3 7% 4 5% 5% 4 6% 9% 39%	4180
September	1st to 10th	Day	14% 7% 2 6% 4 3 5% 4 5% 8% 44%	2280
	11th to 20th	Day	12% 5% 2 6% 3 4 4 4 6% 9% 44%	2265
	21st to end	Day	16% 7% 2 7% 3 4 5% 4 5% 6% 39%	2052
October	1st to 10th	Day	16% 6% 2 7% 4 4 4 4 6% 7% 40%	1900
	11th to 20th	Day	19% 12% 3 7% 4 4 5% 3 5% 7% 32%	1900
	21st to end	Day	19% 11% 3 7% 4 5% 3 3 4 6% 32%	1924
November	1st to 10th	Day	15% 10% 3 7% 5% 3 4 3 6% 7% 37%	1762
	11th to 20th	Day	15% 13% 5% 10% 7% 5% 4 4 5% 7% 26%	1641
	21st to end	Day	14% 13% 5% 9% 7% 4 4 3 5% 7% 31%	1600
December	1st to 10th	Day	7% 10% 5% 20% 10% 8% 5% 4 5% 5% 20%	2610
	11th to 20th	Day	12% 18% 7% 12% 6% 5% 4 3 3 5% 25%	3008
	21st to end	Day	20% 21% 6% 14% 6% 4 4 3 4 4 15%	3982
January	1st to 10th	Night	8% 12% 5% 14% 11% 5% 4 3 4 5% 30%	6348
	11th to 20th	Night	7% 12% 5% 15% 8% 6% 7% 6% 7% 6% 21%	6360
	21st to end	Night	8% 16% 8% 15% 6% 5% 3 3 5% 5% 26%	6835
February	1st to 10th	Night	7% 13% 5% 11% 6% 5% 6% 4 5% 7% 31%	2600
	11th to 20th	Night	7% 10% 4 10% 5% 5% 5% 5% 5% 7% 36%	2500
	21st to end	Night	13% 11% 4 10% 6% 5% 5% 3 4 6% 33%	1980
March	1st to 10th	Night	10% 7% 2 7% 4 4 4 3 5% 7% 46%	5373
	11th to 20th	Night	8% 9% 4 9% 5% 5% 5% 4 6% 9% 34%	5072
	21st to end	Night	22% 11% 4 10% 4 4 3 3 4 5% 29%	5113
April	1st to 10th	Night	19% 11% 3 8% 5% 4 4 3 4 7% 34%	2000
	11th to 20th	Night	21% 8% 2 6% 4 4 5% 4 4 6% 37%	1975
	21st to end	Night	19% 10% 2 6% 4 4 3 4 6% 7% 36%	1899
May	1st to 10th	Night	14% 8% 2 6% 5% 4 4 3 5% 6% 43%	3596
	11th to 20th	Night	12% 6% 3 6% 3 4 3 3 5% 6% 50%	3596
	21st to end	Night	16% 8% 3 7% 5% 5% 4 3 5% 6% 38%	3942
June	1st to 10th	Night	12% 6% 2 6% 4 4 4 4 6% 8% 45%	1597
	11th to 20th	Night	11% 7% 2 6% 4 5% 5% 4 7% 8% 41%	1520
	21st to end	Night	9% 6% 2 5% 4 5% 5% 4 7% 9% 46%	1520
July	1st to 10th	Night	13% 5% 2 5% 4 3 5% 4 6% 7% 46%	2530
	11th to 20th	Night	5% 4 1 3 3 4 4 4 5% 9% 57%	2530
	21st to end	Night	6% 6% 2 5% 4 3 4 4 5% 8% 53%	2750
August	1st to 10th	Night	11% 5% 2 6% 4 4 5% 4 5% 8% 46%	2566
	11th to 20th	Night	13% 5% 2 5% 4 4 4 4 5% 7% 49%	2855
	21st to end	Night	14% 7% 2 6% 4 4 4 4 5% 6% 45%	3476
September	1st to 10th	Night	9% 6% 2 5% 3 4 4 3 5% 7% 52%	1900
	11th to 20th	Night	11% 6% 2 4 3 3 4 4 4 7% 52%	1900
	21st to end	Night	11% 8% 3 6% 5% 3 3 4 5% 7% 47%	2120
October	1st to 10th	Night	14% 5% 2 6% 4 4 3 4 5% 6% 47%	2280
	11th to 20th	Night	15% 11% 3 7% 4 4 5% 3 5% 6% 37%	2280
	21st to end	Night	18% 11% 3 7% 5% 4 4 4 6% 6% 31%	2674
November	1st to 10th	Night	15% 10% 3 6% 4 4 4 3 5% 7% 38%	2536
	11th to 20th	Night	14% 13% 4 9% 5% 5% 4 4 5% 6% 32%	2755
	21st to end	Night	13% 12% 4 10% 6% 4 5% 4 5% 7% 31%	2800
December	1st to 10th	Night	8% 10% 5% 12% 6% 6% 4 5% 7% 8% 26%	4580
	11th to 20th	Night	11% 17% 6% 16% 7% 4 4 3 4 5% 23%	5199
	21st to end	Night	23% 15% 5% 12% 6% 4 4 3 4 5% 20%	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	61% 4 8% 17% 9%	3618
	11th to 20th	Day	61% 5% 7% 15% 11% 1	3620
	21st to end	Day	58% 4 12% 18% 7%	4141
February	1st to 10th	Day	52% 6% 11% 20% 10% 1	1800
	11th to 20th	Day	48% 7% 12% 23% 9% 1	1794
	21st to end	Day	56% 5% 11% 18% 9% 2	1650
March	1st to 10th	Day	38% 4 14% 22% 16% 5%	4480
	11th to 20th	Day	42% 6% 15% 21% 14% 1	4929
	21st to end	Day	59% 4 8% 16% 12% 1	5817
April	1st to 10th	Day	52% 6% 10% 19% 12%	2400
	11th to 20th	Day	55% 6% 9% 18% 10% 1	2374
	21st to end	Day	56% 6% 11% 17% 11%	2495
May	1st to 10th	Day	38% 5% 10% 29% 16% 1	6357
	11th to 20th	Day	41% 6% 13% 26% 13% 1	6323
	21st to end	Day	46% 6% 10% 24% 14% 1	6949
June	1st to 10th	Day	39% 8% 14% 27% 12% 1	2787
	11th to 20th	Day	44% 8% 12% 22% 13% 1	2660
	21st to end	Day	39% 8% 17% 25% 10% 1	2660
July	1st to 10th	Day	40% 7% 18% 27% 9% 1	4371
	11th to 20th	Day	26% 7% 16% 35% 15% 2	4365
	21st to end	Day	35% 7% 14% 27% 17% 1	4662
August	1st to 10th	Day	40% 6% 14% 26% 13% 1	4356
	11th to 20th	Day	36% 6% 13% 33% 12%	4020
	21st to end	Day	42% 6% 14% 26% 11% 1	4179
September	1st to 10th	Day	39% 5% 15% 26% 14%	2280
	11th to 20th	Day	35% 8% 18% 29% 8% 1	2265
	21st to end	Day	43% 6% 12% 29% 10%	2052
October	1st to 10th	Day	29% 4 10% 36% 21%	3160
	11th to 20th	Day	45% 5% 10% 24% 15% 1	3140
	21st to end	Day	46% 4 16% 27% 8%	3149
November	1st to 10th	Day	47% 6% 12% 21% 12% 2	1762
	11th to 20th	Day	57% 5% 12% 18% 7% 1	1641
	21st to end	Day	53% 6% 14% 20% 6% 1	1600
December	1st to 10th	Day	66% 4 10% 16% 4	2610
	11th to 20th	Day	62% 4 7% 16% 10% 1	3005
	21st to end	Day	73% 4 6% 11% 6%	3982
January	1st to 10th	Night	56% 4 9% 18% 12%	6348
	11th to 20th	Night	60% 6% 8% 14% 13%	6360
	21st to end	Night	59% 5% 9% 18% 9%	6835
February	1st to 10th	Night	51% 5% 10% 21% 11% 2	2600
	11th to 20th	Night	45% 6% 13% 24% 10% 1	2501
	21st to end	Night	52% 4 13% 19% 9% 2	1980
March	1st to 10th	Night	37% 5% 15% 24% 14% 5%	5373
	11th to 20th	Night	44% 6% 16% 21% 11% 2	5072
	21st to end	Night	58% 4 9% 17% 12%	5113
April	1st to 10th	Night	51% 6% 7% 18% 17% 1	2000
	11th to 20th	Night	47% 5% 11% 21% 13% 3	1975
	21st to end	Night	46% 6% 9% 22% 14% 2	1899
May	1st to 10th	Night	40% 7% 12% 20% 19% 2	3620
	11th to 20th	Night	35% 5% 12% 26% 18% 3	3597
	21st to end	Night	45% 6% 11% 22% 14% 1	3950
June	1st to 10th	Night	35% 8% 15% 27% 14% 1	1597
	11th to 20th	Night	38% 8% 14% 23% 15% 2	1520
	21st to end	Night	33% 9% 15% 29% 12% 2	1520
July	1st to 10th	Night	37% 6% 19% 23% 14% 2	2490
	11th to 20th	Night	23% 7% 14% 36% 18% 2	2482
	21st to end	Night	29% 7% 12% 32% 18% 2	2662
August	1st to 10th	Night	36% 6% 16% 27% 14% 2	2557
	11th to 20th	Night	34% 7% 15% 30% 14% 1	2882
	21st to end	Night	39% 5% 16% 24% 15% 2	3476
September	1st to 10th	Night	31% 7% 13% 32% 16% 1	1900
	11th to 20th	Night	32% 7% 14% 34% 14%	1900
	21st to end	Night	36% 7% 12% 31% 13% 1	2120
October	1st to 10th	Night	28% 4 8% 35% 23% 3	3800
	11th to 20th	Night	36% 5% 10% 30% 18% 1	3779
	21st to end	Night	52% 4 9% 22% 13%	4399
November	1st to 10th	Night	46% 4 13% 23% 13% 1	2536
	11th to 20th	Night	53% 6% 13% 16% 11% 1	2755
	21st to end	Night	53% 5% 14% 21% 5% 1	2800
December	1st to 10th	Night	53% 6% 17% 20% 4 1	4580
	11th to 20th	Night	65% 4 8% 14% 9%	5201
	21st to end	Night	68% 4 6% 13% 8%	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	15% 13% 33% 25% 12% 2	300
	11th to 20th	Day	22% 10% 35% 25% 7% 1	300
	21st to end	Day	18% 10% 37% 28% 6% 2	330
February	1st to 10th	Day	13% 13% 48% 17% 6% 3	300
	11th to 20th	Day	14% 15% 43% 19% 8%	300
	21st to end	Day	16% 14% 43% 23% 4 1	249
March	1st to 10th	Day	16% 15% 39% 19% 10% 1	300
	11th to 20th	Day	17% 14% 38% 20% 9% 2	300
	21st to end	Day	22% 13% 30% 24% 8% 3	476
April	1st to 10th	Day	22% 16% 33% 22% 6% 1	500
	11th to 20th	Day	27% 15% 28% 21% 9% 2	492
	21st to end	Day	22% 14% 30% 22% 9% 2	530
May	1st to 10th	Day	18% 13% 31% 28% 8% 2	703
	11th to 20th	Day	19% 12% 27% 24% 14% 3	725
	21st to end	Day	19% 10% 25% 27% 13% 6%	789
June	1st to 10th	Day	13% 7% 30% 30% 16% 5%	726
	11th to 20th	Day	14% 9% 33% 27% 13% 4	680
	21st to end	Day	12% 8% 29% 29% 15% 6%	680
July	1st to 10th	Day	10% 4 19% 30% 26% 11%	671
	11th to 20th	Day	9% 5% 28% 31% 18% 9%	668
	21st to end	Day	6% 3 24% 34% 24% 8%	739
August	1st to 10th	Day	11% 5% 24% 30% 23% 8%	676
	11th to 20th	Day	16% 4 17% 27% 27% 9%	631
	21st to end	Day	14% 5% 25% 28% 21% 6%	539
September	1st to 10th	Day	18% 6% 23% 26% 21% 6%	490
	11th to 20th	Day	11% 5% 26% 34% 20% 4	490
	21st to end	Day	17% 9% 27% 28% 14% 5%	452
October	1st to 10th	Day	15% 12% 26% 28% 13% 6%	300
	11th to 20th	Day	22% 17% 31% 22% 7% 1	300
	21st to end	Day	24% 14% 39% 18% 4 1	330
November	1st to 10th	Day	21% 11% 31% 26% 8% 2	300
	11th to 20th	Day	19% 16% 38% 22% 5%	300
	21st to end	Day	20% 14% 41% 20% 6%	300
December	1st to 10th	Day	13% 13% 47% 21% 6%	300
	11th to 20th	Day	21% 16% 39% 19% 5%	300
	21st to end	Day	28% 14% 35% 18% 5% 1	330
January	1st to 10th	Night	14% 12% 36% 30% 8% 1	1000
	11th to 20th	Night	17% 10% 38% 28% 5% 1	1000
	21st to end	Night	18% 8% 37% 30% 7% 1	1100
February	1st to 10th	Night	14% 11% 38% 30% 6% 1	1000
	11th to 20th	Night	13% 11% 42% 27% 8%	946
	21st to end	Night	19% 12% 38% 27% 4	660
March	1st to 10th	Night	17% 10% 36% 30% 6% 1	800
	11th to 20th	Night	16% 13% 35% 28% 8% 1	640
	21st to end	Night	23% 9% 31% 26% 8% 2	660
April	1st to 10th	Night	22% 12% 35% 24% 6% 1	600
	11th to 20th	Night	25% 9% 31% 28% 7%	593
	21st to end	Night	22% 8% 33% 30% 8% 1	600
May	1st to 10th	Night	23% 8% 33% 30% 6% 1	600
	11th to 20th	Night	19% 7% 33% 31% 9% 1	591
	21st to end	Night	17% 5% 25% 37% 15% 1	650
June	1st to 10th	Night	13% 8% 28% 37% 14% 1	599
	11th to 20th	Night	14% 6% 29% 40% 9% 1	570
	21st to end	Night	11% 4 24% 43% 16% 1	570
July	1st to 10th	Night	7% 3 21% 39% 28% 2	555
	11th to 20th	Night	10% 4 22% 36% 26% 2	552
	21st to end	Night	6% 2 20% 43% 27% 3	624
August	1st to 10th	Night	9% 2 16% 46% 25% 2	567
	11th to 20th	Night	15% 3 18% 33% 29% 3	564
	21st to end	Night	15% 4 20% 37% 22% 2	627
September	1st to 10th	Night	10% 4 26% 38% 19% 4	570
	11th to 20th	Night	14% 4 27% 34% 19% 2	570
	21st to end	Night	13% 8% 30% 35% 13% 1	755
October	1st to 10th	Night	16% 7% 29% 31% 16% 1	760
	11th to 20th	Night	19% 11% 34% 28% 7% 1	760
	21st to end	Night	23% 9% 33% 27% 8%	836
November	1st to 10th	Night	20% 9% 33% 29% 7% 1	780
	11th to 20th	Night	21% 11% 40% 22% 6%	955
	21st to end	Night	19% 14% 37% 24% 6%	1000
December	1st to 10th	Night	17% 10% 40% 24% 8% 1	1000
	11th to 20th	Night	20% 11% 37% 24% 8% 1	1000
	21st to end	Night	26% 12% 32% 24% 5%	1100

Page generated at 2025-06-07 09:28:14. Version ac07

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