Bangs Falls
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Bangs Falls clear sky chart from 2005-11-06 to 2026-08-15.

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	20% 11% 4 8% 5% 4 4 3 5% 6% 30%	145093
	Night	20% 11% 4 9% 5% 4 4 3 5% 6% 29%	136932
Transparency	Day	54% 4 11% 19% 11% 1	148684
	Night	55% 4 11% 20% 11% 1	141430
Seeing	Day	30% 18% 31% 15% 5% 1	19708
	Night	28% 15% 31% 20% 5%	27053

By Month

Percentage Cloud Cover NE (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% 16% 7% 17% 8% 6% 4 3 3 5% 16%	4690
	11th to 20th	Day	18% 15% 8% 20% 7% 6% 4 3 4 4 11%	5106
	21st to end	Day	15% 12% 5% 12% 9% 7% 6% 4 5% 5% 21%	5781
February	1st to 10th	Day	19% 14% 5% 11% 6% 4 5% 4 5% 6% 21%	1890
	11th to 20th	Day	17% 13% 4 13% 6% 5% 5% 4 5% 5% 23%	1843
	21st to end	Day	13% 15% 4 9% 6% 5% 5% 3 5% 6% 29%	1611
March	1st to 10th	Day	24% 14% 5% 11% 7% 5% 3 2 3 4 22%	5035
	11th to 20th	Day	19% 17% 4 7% 4 4 4 3 4 6% 29%	5090
	21st to end	Day	28% 15% 5% 9% 5% 4 4 2 3 4 20%	5587
April	1st to 10th	Day	26% 15% 4 7% 4 3 3 2 4 5% 27%	2467
	11th to 20th	Day	23% 11% 3 6% 4 3 3 3 5% 6% 34%	2611
	21st to end	Day	24% 11% 2 5% 4 4 4 2 4 6% 34%	2730
May	1st to 10th	Day	30% 11% 3 7% 4 4 4 3 4 5% 26%	7639
	11th to 20th	Day	22% 11% 3 7% 4 4 4 3 5% 6% 32%	8160
	21st to end	Day	20% 12% 4 7% 4 4 4 3 5% 7% 30%	9059
June	1st to 10th	Day	24% 10% 3 7% 5% 4 4 3 5% 7% 29%	2940
	11th to 20th	Day	21% 8% 3 7% 5% 4 4 3 5% 6% 36%	3096
	21st to end	Day	24% 9% 3 7% 5% 4 4 4 5% 8% 27%	3150
July	1st to 10th	Day	20% 8% 3 7% 5% 4 5% 4 6% 8% 31%	8802
	11th to 20th	Day	17% 8% 3 6% 4 4 5% 3 5% 8% 38%	8280
	21st to end	Day	17% 7% 2 6% 4 4 4 4 6% 9% 37%	8412
August	1st to 10th	Day	22% 10% 3 7% 4 4 5% 4 5% 7% 29%	4365
	11th to 20th	Day	15% 8% 3 7% 5% 4 5% 3 7% 8% 35%	4227
	21st to end	Day	10% 6% 2 5% 3 4 4 4 6% 9% 47%	4543
September	1st to 10th	Day	17% 7% 1 6% 4 4 4 4 5% 7% 42%	2400
	11th to 20th	Day	18% 8% 2 5% 3 3 3 3 4 6% 45%	2261
	21st to end	Day	19% 8% 2 6% 3 4 3 3 4 5% 43%	2174
October	1st to 10th	Day	19% 7% 3 5% 4 3 4 3 5% 8% 39%	2000
	11th to 20th	Day	19% 9% 3 6% 4 4 5% 4 5% 7% 33%	2000
	21st to end	Day	21% 10% 3 8% 5% 3 4 3 4 6% 31%	2200
November	1st to 10th	Day	20% 11% 3 8% 4 4 4 3 4 6% 32%	1748
	11th to 20th	Day	22% 12% 5% 9% 5% 5% 5% 3 4 7% 25%	1680
	21st to end	Day	21% 13% 5% 10% 6% 5% 4 3 4 4 25%	1680
December	1st to 10th	Day	24% 13% 6% 9% 5% 4 4 4 5% 6% 21%	2690
	11th to 20th	Day	28% 12% 3 8% 5% 5% 4 3 4 6% 23%	3076
	21st to end	Day	20% 15% 6% 10% 5% 4 4 2 4 5% 25%	4070
January	1st to 10th	Night	15% 15% 7% 20% 8% 6% 5% 3 4 4 14%	8234
	11th to 20th	Night	22% 15% 6% 17% 6% 5% 4 3 4 4 14%	7781
	21st to end	Night	13% 12% 4 14% 11% 8% 6% 4 5% 6% 18%	8400
February	1st to 10th	Night	19% 12% 4 10% 7% 5% 5% 4 6% 6% 21%	2730
	11th to 20th	Night	17% 12% 4 11% 7% 5% 6% 4 6% 5% 23%	2663
	21st to end	Night	13% 13% 5% 9% 6% 4 5% 4 6% 6% 28%	2191
March	1st to 10th	Night	25% 14% 4 9% 7% 4 4 3 4 4 22%	5025
	11th to 20th	Night	20% 14% 5% 8% 5% 4 4 3 5% 7% 26%	5089
	21st to end	Night	30% 12% 4 8% 3 3 3 2 4 5% 26%	5587
April	1st to 10th	Night	25% 13% 3 7% 4 4 4 3 4 5% 29%	2153
	11th to 20th	Night	26% 10% 2 5% 3 4 4 3 4 6% 32%	1956
	21st to end	Night	25% 9% 3 7% 4 4 3 2 4 5% 33%	1890
May	1st to 10th	Night	28% 13% 3 7% 4 4 3 2 4 4 25%	5259
	11th to 20th	Night	24% 13% 3 7% 4 3 4 3 4 5% 30%	4726
	21st to end	Night	16% 14% 4 8% 5% 4 4 3 5% 6% 31%	5147
June	1st to 10th	Night	27% 8% 3 6% 3 3 3 3 5% 6% 33%	1680
	11th to 20th	Night	21% 9% 3 6% 4 3 4 3 5% 6% 36%	1537
	21st to end	Night	25% 9% 3 7% 5% 4 4 3 5% 7% 28%	1470
July	1st to 10th	Night	20% 10% 3 7% 4 4 5% 4 6% 7% 29%	4110
	11th to 20th	Night	20% 7% 2 6% 4 4 4 3 5% 7% 38%	4710
	21st to end	Night	19% 7% 2 6% 3 3 4 3 5% 7% 40%	5655
August	1st to 10th	Night	25% 8% 3 6% 3 3 3 3 4 6% 36%	3005
	11th to 20th	Night	17% 8% 3 8% 4 4 4 3 5% 6% 38%	2909
	21st to end	Night	10% 6% 2 5% 4 3 4 3 5% 7% 51%	3355
September	1st to 10th	Night	17% 6% 3 5% 3 3 3 2 4 7% 46%	2000
	11th to 20th	Night	19% 7% 2 5% 2 2 3 3 4 6% 46%	2135
	21st to end	Night	20% 8% 3 6% 5% 4 3 3 4 6% 38%	2225
October	1st to 10th	Night	19% 7% 2 6% 4 3 4 3 6% 6% 42%	2400
	11th to 20th	Night	20% 9% 2 5% 4 4 3 3 5% 6% 39%	2400
	21st to end	Night	24% 7% 2 6% 4 4 4 4 4 6% 34%	2640
November	1st to 10th	Night	20% 8% 3 6% 5% 4 4 3 5% 7% 34%	2767
	11th to 20th	Night	20% 12% 3 8% 5% 5% 4 4 6% 6% 27%	2940
	21st to end	Night	21% 11% 4 8% 5% 4 4 4 5% 7% 27%	2940
December	1st to 10th	Night	16% 12% 5% 12% 6% 5% 5% 4 6% 7% 23%	4720
	11th to 20th	Night	25% 11% 3 7% 4 4 3 3 5% 6% 27%	5353
	21st to end	Night	24% 12% 4 9% 6% 3 3 3 4 5% 28%	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	67% 4 11% 13% 4	4691
	11th to 20th	Day	74% 4 8% 10% 3	5139
	21st to end	Day	60% 5% 8% 13% 12% 2	5781
February	1st to 10th	Day	63% 3 12% 15% 7% 1	1890
	11th to 20th	Day	60% 4 11% 18% 7%	1851
	21st to end	Day	54% 3 11% 19% 11% 3	1611
March	1st to 10th	Day	66% 2 8% 13% 8% 2	5039
	11th to 20th	Day	56% 3 14% 19% 8% 1	5090
	21st to end	Day	67% 3 4 14% 11% 1	5587
April	1st to 10th	Day	61% 3 7% 14% 14% 2	2467
	11th to 20th	Day	52% 4 9% 22% 13% 1	2611
	21st to end	Day	53% 3 9% 19% 13% 3	2730
May	1st to 10th	Day	60% 3 11% 16% 9% 1	7651
	11th to 20th	Day	54% 4 11% 21% 9% 1	8164
	21st to end	Day	54% 4 12% 16% 13% 2	9060
June	1st to 10th	Day	55% 4 10% 20% 12%	2940
	11th to 20th	Day	49% 4 11% 21% 13% 2	3096
	21st to end	Day	56% 5% 11% 16% 10% 1	3150
July	1st to 10th	Day	51% 3 14% 20% 10% 2	8728
	11th to 20th	Day	45% 3 11% 28% 13%	8204
	21st to end	Day	44% 4 15% 23% 13% 1	8227
August	1st to 10th	Day	54% 5% 12% 19% 10% 1	4352
	11th to 20th	Day	46% 4 14% 27% 9% 1	4266
	21st to end	Day	34% 4 13% 28% 20% 1	4543
September	1st to 10th	Day	41% 4 12% 25% 16% 2	2400
	11th to 20th	Day	42% 3 9% 26% 19% 2	2261
	21st to end	Day	44% 4 7% 24% 19% 2	2174
October	1st to 10th	Day	44% 5% 9% 27% 13% 1	3260
	11th to 20th	Day	40% 5% 9% 23% 23% 1	3240
	21st to end	Day	45% 3 13% 24% 11% 4	3538
November	1st to 10th	Day	53% 4 11% 21% 10% 1	1748
	11th to 20th	Day	57% 4 12% 18% 8% 1	1680
	21st to end	Day	60% 4 12% 17% 6%	1680
December	1st to 10th	Day	59% 5% 10% 20% 5%	2690
	11th to 20th	Day	62% 3 9% 16% 10%	3075
	21st to end	Day	59% 2 13% 16% 9%	4070
January	1st to 10th	Night	69% 5% 9% 13% 4	8234
	11th to 20th	Night	70% 4 9% 12% 5%	7823
	21st to end	Night	61% 5% 9% 14% 9% 1	8400
February	1st to 10th	Night	60% 4 11% 16% 8% 1	2730
	11th to 20th	Night	59% 3 11% 18% 9% 1	2666
	21st to end	Night	53% 4 12% 20% 9% 1	2191
March	1st to 10th	Night	64% 3 7% 12% 13% 1	5034
	11th to 20th	Night	58% 3 14% 17% 7% 1	5090
	21st to end	Night	61% 2 7% 18% 10% 1	5587
April	1st to 10th	Night	58% 3 8% 15% 14% 3	2153
	11th to 20th	Night	53% 2 9% 21% 12% 1	1956
	21st to end	Night	54% 2 8% 21% 12% 2	1890
May	1st to 10th	Night	63% 2 10% 16% 8% 1	5265
	11th to 20th	Night	57% 3 9% 20% 9% 2	4727
	21st to end	Night	55% 4 11% 19% 11% 1	5148
June	1st to 10th	Night	52% 4 11% 23% 10%	1680
	11th to 20th	Night	50% 3 12% 21% 12% 1	1537
	21st to end	Night	57% 5% 11% 15% 11% 1	1470
July	1st to 10th	Night	53% 4 13% 21% 8%	4075
	11th to 20th	Night	47% 3 10% 23% 16% 1	4662
	21st to end	Night	44% 3 12% 26% 15% 1	5526
August	1st to 10th	Night	51% 3 12% 22% 11%	2993
	11th to 20th	Night	46% 4 17% 25% 8%	2936
	21st to end	Night	33% 3 14% 28% 21% 1	3354
September	1st to 10th	Night	39% 4 10% 28% 17% 2	2000
	11th to 20th	Night	40% 2 8% 30% 18% 2	2135
	21st to end	Night	47% 3 7% 26% 15% 2	2225
October	1st to 10th	Night	45% 4 12% 25% 14% 1	3920
	11th to 20th	Night	35% 3 11% 28% 23%	3899
	21st to end	Night	41% 4 10% 26% 18% 1	4252
November	1st to 10th	Night	48% 4 14% 22% 12% 1	2767
	11th to 20th	Night	56% 4 12% 20% 9%	2940
	21st to end	Night	55% 5% 15% 18% 7% 1	2940
December	1st to 10th	Night	55% 5% 11% 25% 4	4720
	11th to 20th	Night	55% 3 11% 18% 11% 1	5355
	21st to end	Night	58% 3 11% 17% 10% 1	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	34% 23% 29% 12% 2	430
	11th to 20th	Day	37% 21% 26% 13% 4	430
	21st to end	Day	27% 26% 32% 12% 3 1	473
February	1st to 10th	Day	32% 21% 29% 16% 2	430
	11th to 20th	Day	36% 25% 25% 13% 1	426
	21st to end	Day	32% 21% 30% 15% 2 1	385
March	1st to 10th	Day	36% 23% 30% 8% 3	540
	11th to 20th	Day	35% 25% 26% 9% 4 1	540
	21st to end	Day	38% 25% 24% 9% 4	594
April	1st to 10th	Day	43% 23% 25% 6% 2	540
	11th to 20th	Day	35% 25% 28% 9% 3	532
	21st to end	Day	35% 21% 28% 11% 4	540
May	1st to 10th	Day	35% 25% 29% 8% 2 1	543
	11th to 20th	Day	29% 20% 30% 16% 4 1	752
	21st to end	Day	32% 18% 31% 15% 4 1	845
June	1st to 10th	Day	33% 14% 32% 18% 3	780
	11th to 20th	Day	25% 17% 35% 18% 5% 1	780
	21st to end	Day	31% 14% 31% 18% 5% 1	780
July	1st to 10th	Day	23% 12% 37% 20% 7% 1	770
	11th to 20th	Day	23% 9% 37% 21% 9% 1	768
	21st to end	Day	24% 12% 36% 22% 6% 1	651
August	1st to 10th	Day	18% 10% 38% 25% 8% 1	566
	11th to 20th	Day	19% 15% 35% 21% 9% 2	535
	21st to end	Day	20% 14% 35% 21% 9% 2	583
September	1st to 10th	Day	19% 14% 35% 23% 7% 1	530
	11th to 20th	Day	24% 15% 31% 19% 8% 4	530
	21st to end	Day	21% 17% 34% 18% 7% 2	515
October	1st to 10th	Day	23% 16% 32% 19% 8% 2	420
	11th to 20th	Day	27% 18% 29% 19% 5% 2	420
	21st to end	Day	32% 19% 27% 15% 6% 1	462
November	1st to 10th	Day	29% 18% 32% 14% 7% 1	425
	11th to 20th	Day	38% 20% 23% 14% 4	430
	21st to end	Day	34% 21% 29% 10% 4 1	430
December	1st to 10th	Day	39% 19% 26% 15% 2	430
	11th to 20th	Day	44% 21% 23% 10% 2	430
	21st to end	Day	37% 22% 24% 12% 3 1	473
January	1st to 10th	Night	31% 21% 31% 15% 2	950
	11th to 20th	Night	32% 19% 27% 19% 3	867
	21st to end	Night	26% 21% 32% 17% 3	924
February	1st to 10th	Night	31% 18% 30% 19% 2	840
	11th to 20th	Night	30% 21% 33% 14% 2	823
	21st to end	Night	23% 18% 36% 18% 4	692
March	1st to 10th	Night	30% 19% 32% 17% 2	840
	11th to 20th	Night	28% 20% 29% 19% 4	840
	21st to end	Night	28% 20% 32% 15% 4	924
April	1st to 10th	Night	37% 17% 31% 13% 2	683
	11th to 20th	Night	32% 18% 34% 14% 2	624
	21st to end	Night	29% 17% 31% 18% 5%	630
May	1st to 10th	Night	32% 15% 31% 18% 4	630
	11th to 20th	Night	29% 13% 35% 20% 4	622
	21st to end	Night	23% 15% 39% 18% 4	682
June	1st to 10th	Night	31% 8% 38% 20% 4	630
	11th to 20th	Night	23% 12% 36% 22% 6%	487
	21st to end	Night	29% 7% 34% 24% 6%	420
July	1st to 10th	Night	23% 6% 39% 24% 9%	410
	11th to 20th	Night	19% 8% 39% 26% 8%	612
	21st to end	Night	20% 6% 37% 30% 7%	689
August	1st to 10th	Night	17% 8% 34% 30% 10% 1	628
	11th to 20th	Night	19% 7% 33% 30% 10% 1	605
	21st to end	Night	16% 8% 35% 28% 12% 1	660
September	1st to 10th	Night	22% 8% 34% 26% 10% 1	600
	11th to 20th	Night	21% 10% 28% 27% 13% 2	735
	21st to end	Night	23% 12% 31% 23% 10% 1	800
October	1st to 10th	Night	22% 11% 32% 25% 9% 1	800
	11th to 20th	Night	25% 15% 29% 21% 9% 1	800
	21st to end	Night	30% 14% 29% 22% 5%	880
November	1st to 10th	Night	29% 13% 29% 22% 5% 1	881
	11th to 20th	Night	31% 18% 26% 20% 5%	950
	21st to end	Night	30% 21% 27% 17% 6%	950
December	1st to 10th	Night	33% 16% 29% 18% 4	950
	11th to 20th	Night	35% 22% 26% 14% 3	950
	21st to end	Night	33% 18% 28% 18% 3	1045

Page generated at 2026-08-12 04:37:20. Version ac07

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