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 2026-10-14.

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% 37%	150216
	Night	12% 10% 4 9% 5% 4 4 4 5% 7% 36%	141936
Transparency	Day	45% 5% 12% 25% 12% 1	153689
	Night	47% 5% 12% 23% 13% 1	146539
Seeing	Day	16% 10% 30% 26% 13% 4	18748
	Night	17% 9% 32% 31% 11% 1	28520

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	9% 13% 6% 18% 9% 6% 5% 3 4 5% 23%	4691
	11th to 20th	Day	7% 15% 7% 15% 6% 6% 6% 8% 8% 6% 18%	4710
	21st to end	Day	6% 12% 6% 13% 5% 5% 6% 5% 6% 8% 28%	5371
February	1st to 10th	Day	8% 11% 6% 13% 6% 5% 6% 4 5% 7% 29%	1890
	11th to 20th	Day	9% 11% 4 10% 6% 5% 4 5% 6% 6% 33%	1877
	21st to end	Day	11% 12% 5% 11% 7% 5% 5% 4 6% 5% 29%	1730
March	1st to 10th	Day	13% 9% 2 4 4 4 4 3 4 7% 46%	4580
	11th to 20th	Day	11% 8% 3 9% 5% 5% 5% 4 6% 8% 37%	5038
	21st to end	Day	22% 11% 4 10% 5% 4 4 3 4 5% 29%	5943
April	1st to 10th	Day	16% 13% 4 7% 5% 5% 4 4 6% 7% 30%	2520
	11th to 20th	Day	20% 11% 4 9% 4 4 5% 4 5% 6% 29%	2494
	21st to end	Day	20% 12% 3 7% 6% 5% 5% 4 5% 5% 29%	2619
May	1st to 10th	Day	12% 5% 2 6% 4 4 5% 4 5% 7% 46%	8212
	11th to 20th	Day	14% 7% 2 7% 4 4 4 4 6% 7% 43%	8222
	21st to end	Day	14% 8% 3 6% 4 5% 5% 4 6% 7% 39%	9047
June	1st to 10th	Day	14% 6% 3 6% 5% 4 4 4 6% 8% 40%	2940
	11th to 20th	Day	14% 7% 3 7% 6% 6% 5% 4 6% 7% 35%	2940
	21st to end	Day	12% 6% 3 7% 5% 5% 5% 4 6% 10% 37%	2940
July	1st to 10th	Day	12% 5% 2 6% 4 4 5% 4 7% 10% 40%	8280
	11th to 20th	Day	7% 4 1 4 3 3 4 4 7% 10% 53%	8280
	21st to end	Day	11% 6% 2 5% 4 4 5% 4 6% 8% 46%	8990
August	1st to 10th	Day	12% 7% 3 6% 4 4 5% 3 6% 7% 45%	6415
	11th to 20th	Day	13% 5% 2 6% 4 4 5% 4 6% 9% 44%	5858
	21st to end	Day	12% 6% 2 7% 4 5% 5% 4 6% 9% 41%	6080
September	1st to 10th	Day	14% 7% 2 6% 4 3 5% 4 5% 8% 43%	2520
	11th to 20th	Day	13% 5% 2 6% 3 4 4 4 6% 9% 43%	2503
	21st to end	Day	15% 7% 3 8% 3 4 5% 4 5% 6% 40%	2268
October	1st to 10th	Day	14% 6% 2 7% 4 4 4 4 5% 7% 42%	2100
	11th to 20th	Day	19% 12% 3 7% 3 4 5% 3 5% 7% 32%	2030
	21st to end	Day	18% 11% 3 8% 5% 5% 4 3 4 7% 32%	2025
November	1st to 10th	Day	14% 10% 3 7% 5% 3 4 3 5% 7% 37%	1852
	11th to 20th	Day	14% 13% 4 10% 7% 5% 4 4 5% 7% 27%	1723
	21st to end	Day	14% 13% 4 9% 7% 4 4 3 5% 7% 30%	1680
December	1st to 10th	Day	7% 11% 5% 21% 10% 8% 5% 4 5% 5% 20%	2690
	11th to 20th	Day	12% 17% 7% 12% 6% 5% 4 3 4 5% 25%	3088
	21st to end	Day	20% 21% 6% 14% 6% 4 4 3 4 4 15%	4070
January	1st to 10th	Night	9% 14% 5% 14% 10% 5% 4 3 4 5% 28%	8232
	11th to 20th	Night	6% 14% 6% 15% 8% 6% 7% 7% 7% 6% 19%	8280
	21st to end	Night	6% 12% 7% 14% 6% 6% 5% 4 5% 6% 29%	8841
February	1st to 10th	Night	8% 13% 5% 11% 6% 5% 5% 4 5% 7% 31%	2730
	11th to 20th	Night	8% 10% 4 10% 5% 5% 5% 5% 5% 7% 36%	2628
	21st to end	Night	12% 11% 4 10% 7% 6% 5% 3 4 5% 33%	2076
March	1st to 10th	Night	10% 7% 2 7% 4 4 4 4 5% 8% 45%	5493
	11th to 20th	Night	9% 10% 4 9% 5% 5% 5% 4 6% 9% 34%	5184
	21st to end	Night	22% 11% 4 10% 4 4 3 3 4 5% 29%	5227
April	1st to 10th	Night	19% 11% 3 8% 5% 4 4 3 4 7% 33%	2100
	11th to 20th	Night	21% 8% 2 6% 4 4 4 3 4 6% 37%	2075
	21st to end	Night	18% 10% 3 6% 4 4 3 4 6% 7% 36%	1994
May	1st to 10th	Night	12% 7% 2 6% 5% 4 4 4 6% 8% 44%	4671
	11th to 20th	Night	14% 6% 3 7% 4 4 4 3 5% 6% 45%	4670
	21st to end	Night	13% 8% 3 7% 5% 5% 4 4 6% 7% 39%	5139
June	1st to 10th	Night	13% 6% 2 6% 4 4 5% 3 5% 7% 44%	1680
	11th to 20th	Night	12% 8% 2 6% 4 5% 5% 5% 7% 7% 39%	1680
	21st to end	Night	10% 6% 2 5% 4 5% 4 4 6% 9% 45%	1680
July	1st to 10th	Night	11% 6% 3 6% 4 4 5% 4 6% 9% 41%	4708
	11th to 20th	Night	7% 4 1 4 3 3 4 4 5% 10% 55%	4707
	21st to end	Night	7% 5% 2 6% 4 3 4 4 6% 9% 50%	5117
August	1st to 10th	Night	10% 5% 3 6% 4 4 4 3 5% 8% 48%	3751
	11th to 20th	Night	11% 5% 2 6% 4 4 4 4 6% 8% 45%	4203
	21st to end	Night	12% 6% 2 6% 4 4 4 4 6% 6% 46%	5046
September	1st to 10th	Night	10% 6% 2 5% 3 4 3 3 5% 6% 51%	2100
	11th to 20th	Night	12% 6% 2 5% 3 3 4 4 4 7% 50%	2100
	21st to end	Night	11% 8% 3 5% 4 3 3 4 4 6% 48%	2344
October	1st to 10th	Night	13% 5% 2 6% 4 4 3 4 5% 6% 47%	2520
	11th to 20th	Night	16% 10% 3 7% 4 4 5% 3 5% 6% 37%	2437
	21st to end	Night	18% 11% 3 7% 5% 4 4 4 6% 6% 32%	2815
November	1st to 10th	Night	15% 10% 3 7% 4 4 4 3 5% 7% 38%	2666
	11th to 20th	Night	13% 13% 4 9% 5% 5% 4 3 5% 6% 33%	2893
	21st to end	Night	13% 12% 4 10% 6% 4 5% 4 5% 6% 30%	2940
December	1st to 10th	Night	8% 11% 5% 13% 6% 6% 4 5% 7% 8% 26%	4720
	11th to 20th	Night	11% 17% 6% 16% 7% 4 4 3 4 5% 23%	5339
	21st to end	Night	23% 15% 5% 12% 6% 4 4 3 4 5% 20%	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	64% 4 8% 15% 8%	4692
	11th to 20th	Day	63% 4 6% 15% 10% 1	4710
	21st to end	Day	53% 4 11% 23% 10%	5371
February	1st to 10th	Day	53% 6% 11% 19% 10% 1	1890
	11th to 20th	Day	48% 6% 12% 24% 9% 1	1886
	21st to end	Day	56% 5% 11% 18% 9% 2	1730
March	1st to 10th	Day	39% 4 14% 22% 16% 5%	4580
	11th to 20th	Day	43% 6% 15% 21% 14% 1	5038
	21st to end	Day	59% 4 9% 16% 12% 1	5945
April	1st to 10th	Day	52% 6% 10% 19% 12%	2520
	11th to 20th	Day	55% 6% 10% 18% 10% 1	2494
	21st to end	Day	55% 6% 11% 17% 11%	2619
May	1st to 10th	Day	36% 5% 9% 32% 17% 1	8250
	11th to 20th	Day	40% 5% 11% 26% 17% 1	8226
	21st to end	Day	43% 5% 9% 25% 15% 2	9061
June	1st to 10th	Day	39% 7% 13% 27% 13% 1	2940
	11th to 20th	Day	45% 8% 11% 23% 12% 1	2940
	21st to end	Day	41% 8% 17% 24% 10% 1	2940
July	1st to 10th	Day	38% 6% 18% 32% 6%	8211
	11th to 20th	Day	26% 5% 14% 39% 16% 1	8205
	21st to end	Day	36% 5% 13% 28% 18%	8794
August	1st to 10th	Day	39% 5% 14% 31% 11% 1	6400
	11th to 20th	Day	38% 5% 18% 30% 10%	5897
	21st to end	Day	40% 5% 15% 31% 9%	6079
September	1st to 10th	Day	39% 5% 15% 27% 14%	2520
	11th to 20th	Day	37% 8% 19% 29% 7% 1	2503
	21st to end	Day	43% 6% 12% 29% 10% 1	2268
October	1st to 10th	Day	28% 4 10% 37% 21% 1	3360
	11th to 20th	Day	45% 5% 10% 24% 15% 1	3270
	21st to end	Day	46% 4 16% 27% 8%	3250
November	1st to 10th	Day	47% 6% 12% 21% 13% 2	1852
	11th to 20th	Day	56% 5% 12% 19% 7% 1	1723
	21st to end	Day	54% 5% 14% 20% 6% 1	1680
December	1st to 10th	Day	66% 4 10% 16% 4	2690
	11th to 20th	Day	61% 4 7% 17% 10% 1	3085
	21st to end	Day	73% 4 6% 11% 6%	4070
January	1st to 10th	Night	59% 3 10% 18% 10%	8233
	11th to 20th	Night	62% 5% 7% 14% 11%	8280
	21st to end	Night	55% 4 8% 19% 13% 1	8841
February	1st to 10th	Night	51% 5% 10% 21% 11% 2	2730
	11th to 20th	Night	45% 6% 13% 24% 10% 1	2629
	21st to end	Night	53% 4 13% 19% 9% 2	2076
March	1st to 10th	Night	37% 5% 15% 25% 14% 5%	5493
	11th to 20th	Night	45% 6% 16% 21% 11% 2	5184
	21st to end	Night	58% 4 9% 16% 12%	5227
April	1st to 10th	Night	51% 6% 7% 18% 17% 1	2100
	11th to 20th	Night	48% 5% 11% 21% 13% 2	2075
	21st to end	Night	47% 6% 10% 22% 14% 2	1994
May	1st to 10th	Night	37% 6% 10% 26% 19% 2	4695
	11th to 20th	Night	40% 5% 10% 24% 19% 3	4671
	21st to end	Night	44% 6% 10% 22% 16% 2	5149
June	1st to 10th	Night	37% 8% 14% 26% 15% 1	1680
	11th to 20th	Night	41% 8% 13% 23% 14% 1	1680
	21st to end	Night	35% 8% 15% 28% 11% 2	1680
July	1st to 10th	Night	39% 5% 18% 27% 9% 1	4670
	11th to 20th	Night	25% 5% 13% 38% 18% 1	4662
	21st to end	Night	31% 5% 14% 31% 18% 1	5002
August	1st to 10th	Night	35% 5% 15% 31% 13% 1	3742
	11th to 20th	Night	37% 6% 18% 28% 11% 1	4230
	21st to end	Night	37% 6% 15% 28% 13% 1	5046
September	1st to 10th	Night	33% 7% 13% 32% 15% 1	2100
	11th to 20th	Night	33% 7% 15% 32% 13%	2100
	21st to end	Night	36% 7% 12% 31% 13% 1	2344
October	1st to 10th	Night	28% 4 8% 35% 22% 3	4040
	11th to 20th	Night	37% 5% 10% 29% 19% 1	3936
	21st to end	Night	52% 4 9% 22% 13%	4540
November	1st to 10th	Night	45% 4 13% 23% 13% 1	2666
	11th to 20th	Night	52% 6% 13% 17% 11% 1	2893
	21st to end	Night	54% 5% 13% 21% 6% 1	2940
December	1st to 10th	Night	54% 5% 17% 20% 4 1	4720
	11th to 20th	Night	64% 4 8% 15% 9%	5341
	21st to end	Night	68% 4 6% 13% 8%	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	15% 13% 34% 25% 11% 2	330
	11th to 20th	Day	21% 11% 35% 25% 6% 1	330
	21st to end	Day	16% 10% 39% 27% 7% 2	363
February	1st to 10th	Day	12% 14% 48% 17% 6% 2	330
	11th to 20th	Day	14% 15% 42% 22% 8%	330
	21st to end	Day	15% 14% 45% 22% 3 1	273
March	1st to 10th	Day	17% 15% 38% 20% 9% 1	330
	11th to 20th	Day	18% 14% 39% 20% 8% 2	330
	21st to end	Day	22% 14% 32% 23% 8% 2	516
April	1st to 10th	Day	22% 16% 34% 21% 6% 1	540
	11th to 20th	Day	27% 15% 28% 20% 9% 2	532
	21st to end	Day	22% 15% 29% 23% 9% 2	571
May	1st to 10th	Day	18% 13% 31% 28% 8% 2	753
	11th to 20th	Day	20% 13% 27% 24% 13% 3	775
	21st to end	Day	18% 10% 26% 28% 13% 6%	844
June	1st to 10th	Day	13% 7% 30% 30% 15% 5%	780
	11th to 20th	Day	16% 9% 34% 26% 12% 3	780
	21st to end	Day	13% 8% 30% 28% 14% 6%	780
July	1st to 10th	Day	10% 4 19% 31% 26% 10%	771
	11th to 20th	Day	9% 4 29% 31% 18% 9%	768
	21st to end	Day	7% 4 24% 35% 23% 7%	849
August	1st to 10th	Day	11% 5% 23% 29% 23% 8%	776
	11th to 20th	Day	16% 4 19% 28% 25% 8%	727
	21st to end	Day	14% 6% 24% 29% 21% 6%	627
September	1st to 10th	Day	18% 6% 24% 27% 20% 6%	570
	11th to 20th	Day	12% 5% 26% 34% 19% 3	570
	21st to end	Day	16% 8% 25% 30% 15% 6%	528
October	1st to 10th	Day	14% 13% 29% 26% 14% 6%	360
	11th to 20th	Day	22% 17% 31% 22% 6% 1	339
	21st to end	Day	22% 14% 38% 20% 4 1	363
November	1st to 10th	Day	21% 13% 32% 25% 7% 2	330
	11th to 20th	Day	19% 17% 36% 23% 5%	330
	21st to end	Day	22% 13% 41% 19% 5%	330
December	1st to 10th	Day	13% 13% 47% 21% 6%	330
	11th to 20th	Day	20% 16% 39% 19% 5%	330
	21st to end	Day	27% 15% 37% 16% 4 1	363
January	1st to 10th	Night	14% 12% 36% 30% 8%	1050
	11th to 20th	Night	17% 11% 39% 28% 5% 1	1050
	21st to end	Night	17% 8% 38% 30% 6% 1	1155
February	1st to 10th	Night	14% 11% 38% 30% 6% 1	1050
	11th to 20th	Night	13% 11% 41% 27% 7%	994
	21st to end	Night	18% 12% 39% 27% 4	692
March	1st to 10th	Night	17% 10% 35% 30% 6% 1	840
	11th to 20th	Night	17% 13% 35% 27% 7% 1	672
	21st to end	Night	23% 10% 32% 26% 8% 2	693
April	1st to 10th	Night	23% 12% 36% 24% 6% 1	630
	11th to 20th	Night	25% 9% 31% 28% 7%	623
	21st to end	Night	22% 8% 33% 30% 7% 1	630
May	1st to 10th	Night	22% 8% 33% 30% 6% 1	630
	11th to 20th	Night	19% 8% 34% 30% 8% 1	621
	21st to end	Night	17% 5% 26% 37% 15% 1	683
June	1st to 10th	Night	14% 8% 28% 36% 13% 1	630
	11th to 20th	Night	15% 7% 30% 38% 9%	630
	21st to end	Night	12% 5% 24% 43% 15% 1	630
July	1st to 10th	Night	9% 3 20% 39% 27% 2	615
	11th to 20th	Night	10% 4 22% 39% 24% 2	612
	21st to end	Night	7% 2 20% 44% 25% 2	690
August	1st to 10th	Night	9% 3 17% 45% 25% 1	627
	11th to 20th	Night	14% 3 19% 34% 27% 3	624
	21st to end	Night	15% 4 19% 37% 22% 2	693
September	1st to 10th	Night	11% 4 25% 37% 19% 4	630
	11th to 20th	Night	14% 4 26% 34% 19% 2	630
	21st to end	Night	14% 8% 28% 36% 14% 1	835
October	1st to 10th	Night	16% 7% 30% 31% 15% 1	840
	11th to 20th	Night	19% 11% 35% 27% 6% 1	813
	21st to end	Night	22% 9% 33% 27% 9%	880
November	1st to 10th	Night	20% 9% 33% 29% 7% 1	820
	11th to 20th	Night	20% 11% 40% 22% 7%	1003
	21st to end	Night	19% 14% 37% 24% 6%	1050
December	1st to 10th	Night	17% 10% 40% 24% 7% 1	1050
	11th to 20th	Night	20% 12% 37% 23% 7% 1	1050
	21st to end	Night	26% 11% 33% 24% 5%	1155

Page generated at 2026-10-11 04:06:27. Version ac07

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