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 2025-04-11.

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	21% 11% 4 8% 5% 4 4 3 5% 6% 29%	114300
	Night	20% 11% 4 9% 5% 4 4 3 5% 6% 29%	114065
Transparency	Day	54% 4 11% 19% 11% 1	117933
	Night	54% 4 11% 20% 10% 1	118596
Seeing	Day	30% 18% 31% 16% 5% 1	17752
	Night	27% 15% 31% 20% 5%	25365

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% 17% 6% 17% 8% 5% 4 3 3 5% 17%	3616
	11th to 20th	Day	15% 14% 7% 20% 7% 6% 5% 3 5% 4 13%	3912
	21st to end	Day	16% 13% 6% 11% 7% 6% 5% 3 5% 5% 24%	4466
February	1st to 10th	Day	20% 14% 5% 11% 6% 4 4 4 5% 5% 21%	1800
	11th to 20th	Day	17% 13% 4 14% 6% 5% 5% 3 5% 5% 22%	1753
	21st to end	Day	13% 15% 4 10% 6% 5% 4 3 5% 6% 28%	1536
March	1st to 10th	Day	24% 14% 5% 11% 7% 5% 3 2 3 4 22%	4925
	11th to 20th	Day	18% 17% 4 7% 4 4 4 3 4 6% 29%	4980
	21st to end	Day	28% 15% 5% 9% 5% 4 4 2 3 4 20%	5466
April	1st to 10th	Day	27% 15% 4 7% 4 3 3 2 4 5% 26%	2350
	11th to 20th	Day	22% 10% 3 5% 4 3 4 3 5% 6% 34%	2359
	21st to end	Day	25% 11% 2 5% 4 4 4 3 4 6% 34%	2470
May	1st to 10th	Day	25% 13% 3 8% 5% 4 4 3 5% 6% 25%	4106
	11th to 20th	Day	24% 12% 3 7% 4 3 4 3 4 5% 30%	4365
	21st to end	Day	19% 8% 3 6% 4 4 4 3 5% 8% 36%	4836
June	1st to 10th	Day	26% 10% 3 7% 4 4 4 3 5% 7% 29%	2660
	11th to 20th	Day	22% 8% 3 7% 4 3 4 3 5% 6% 36%	2801
	21st to end	Day	25% 10% 3 7% 6% 4 4 4 5% 8% 26%	2850
July	1st to 10th	Day	22% 9% 3 6% 4 4 4 4 5% 8% 31%	4710
	11th to 20th	Day	21% 10% 3 6% 4 4 4 3 5% 8% 33%	4440
	21st to end	Day	19% 10% 3 7% 5% 4 4 4 5% 8% 31%	4509
August	1st to 10th	Day	24% 10% 3 7% 4 4 5% 4 5% 7% 28%	4105
	11th to 20th	Day	16% 8% 3 7% 5% 4 5% 3 7% 8% 34%	4045
	21st to end	Day	10% 6% 2 5% 3 4 4 4 6% 9% 47%	4404
September	1st to 10th	Day	17% 7% 1 6% 4 4 4 3 5% 7% 42%	2280
	11th to 20th	Day	18% 8% 2 5% 3 3 3 3 4 6% 44%	2148
	21st to end	Day	20% 8% 2 6% 3 4 3 3 4 5% 42%	2066
October	1st to 10th	Day	19% 7% 3 6% 4 3 4 3 6% 8% 37%	1900
	11th to 20th	Day	19% 8% 2 6% 4 4 5% 4 5% 7% 34%	1900
	21st to end	Day	22% 10% 3 8% 5% 3 4 3 4 6% 31%	2090
November	1st to 10th	Day	20% 11% 3 8% 4 4 3 3 4 6% 33%	1664
	11th to 20th	Day	23% 11% 4 8% 5% 5% 4 3 4 7% 26%	1600
	21st to end	Day	22% 13% 5% 10% 6% 5% 4 3 4 4 25%	1600
December	1st to 10th	Day	24% 12% 6% 9% 5% 4 4 4 5% 6% 20%	2610
	11th to 20th	Day	29% 11% 3 8% 5% 5% 4 3 4 6% 23%	2996
	21st to end	Day	20% 15% 6% 9% 5% 3 4 2 4 5% 26%	3982
January	1st to 10th	Night	14% 15% 6% 20% 7% 5% 4 3 4 4 16%	6349
	11th to 20th	Night	17% 15% 7% 18% 6% 5% 4 4 4 5% 15%	5973
	21st to end	Night	14% 12% 4 14% 9% 6% 6% 4 5% 6% 21%	6490
February	1st to 10th	Night	20% 13% 4 9% 7% 5% 5% 4 6% 6% 22%	2600
	11th to 20th	Night	18% 12% 4 11% 7% 6% 6% 4 6% 5% 22%	2533
	21st to end	Night	13% 13% 5% 9% 6% 4 5% 4 6% 6% 28%	2090
March	1st to 10th	Night	25% 14% 4 9% 7% 4 4 3 4 4 22%	4915
	11th to 20th	Night	20% 14% 5% 8% 5% 4 4 3 5% 7% 26%	4979
	21st to end	Night	30% 12% 4 8% 3 3 3 2 4 5% 26%	5466
April	1st to 10th	Night	25% 13% 3 7% 4 4 4 3 4 5% 29%	2050
	11th to 20th	Night	26% 9% 2 6% 3 3 4 3 4 6% 33%	1775
	21st to end	Night	26% 9% 3 7% 4 4 3 2 4 5% 33%	1710
May	1st to 10th	Night	20% 15% 4 8% 5% 4 3 3 5% 6% 27%	2834
	11th to 20th	Night	23% 12% 3 8% 4 4 4 3 5% 6% 28%	2537
	21st to end	Night	19% 10% 3 8% 5% 4 4 3 5% 7% 32%	2749
June	1st to 10th	Night	28% 8% 3 6% 3 3 3 3 5% 6% 32%	1520
	11th to 20th	Night	21% 9% 3 6% 4 4 4 3 5% 6% 36%	1391
	21st to end	Night	26% 9% 2 7% 5% 3 5% 3 5% 6% 28%	1330
July	1st to 10th	Night	22% 11% 3 7% 5% 4 5% 4 6% 7% 28%	2210
	11th to 20th	Night	24% 8% 3 6% 5% 4 4 3 5% 8% 31%	2530
	21st to end	Night	19% 7% 2 6% 4 4 5% 4 5% 6% 38%	3044
August	1st to 10th	Night	25% 9% 3 6% 3 3 3 2 4 6% 35%	2825
	11th to 20th	Night	18% 8% 3 8% 4 3 4 3 5% 6% 37%	2782
	21st to end	Night	10% 6% 2 5% 4 3 4 3 5% 7% 51%	3252
September	1st to 10th	Night	17% 6% 3 5% 3 3 3 3 4 7% 45%	1900
	11th to 20th	Night	19% 7% 2 5% 2 2 3 3 5% 6% 46%	2028
	21st to end	Night	20% 9% 3 6% 5% 4 3 3 4 6% 38%	2114
October	1st to 10th	Night	20% 7% 2 6% 4 3 4 3 6% 6% 40%	2280
	11th to 20th	Night	19% 8% 2 5% 4 4 3 3 5% 7% 40%	2280
	21st to end	Night	24% 8% 2 6% 4 4 4 4 4 6% 34%	2508
November	1st to 10th	Night	20% 8% 3 6% 5% 4 4 3 5% 7% 35%	2632
	11th to 20th	Night	21% 11% 3 8% 5% 5% 4 4 6% 6% 27%	2800
	21st to end	Night	21% 12% 4 8% 5% 4 4 4 5% 7% 27%	2800
December	1st to 10th	Night	16% 12% 5% 12% 6% 5% 5% 4 6% 7% 23%	4580
	11th to 20th	Night	26% 11% 3 6% 4 4 4 3 5% 6% 28%	5213
	21st to end	Night	24% 12% 4 9% 6% 3 3 3 4 5% 28%	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	67% 3 12% 13% 5%	3617
	11th to 20th	Day	70% 4 11% 12% 3	3945
	21st to end	Day	59% 4 9% 13% 13% 2	4466
February	1st to 10th	Day	63% 3 12% 14% 7% 1	1800
	11th to 20th	Day	62% 3 11% 17% 7%	1761
	21st to end	Day	55% 3 11% 19% 10% 3	1536
March	1st to 10th	Day	67% 2 8% 13% 8% 2	4929
	11th to 20th	Day	56% 3 14% 19% 8% 1	4980
	21st to end	Day	67% 3 4 14% 11% 1	5466
April	1st to 10th	Day	61% 3 7% 14% 13% 2	2350
	11th to 20th	Day	51% 4 9% 22% 13% 1	2359
	21st to end	Day	53% 3 9% 19% 13% 3	2470
May	1st to 10th	Day	59% 3 13% 17% 7% 1	4120
	11th to 20th	Day	56% 4 11% 19% 9% 1	4369
	21st to end	Day	47% 4 16% 19% 13% 1	4836
June	1st to 10th	Day	56% 4 9% 20% 11%	2660
	11th to 20th	Day	50% 4 10% 20% 13% 2	2801
	21st to end	Day	57% 6% 11% 16% 10% 1	2850
July	1st to 10th	Day	51% 4 13% 18% 12% 2	4636
	11th to 20th	Day	51% 3 11% 23% 10% 1	4364
	21st to end	Day	49% 4 14% 21% 11% 1	4365
August	1st to 10th	Day	55% 5% 12% 18% 9% 1	4092
	11th to 20th	Day	47% 4 14% 27% 9%	4084
	21st to end	Day	34% 4 13% 28% 21% 1	4404
September	1st to 10th	Day	41% 4 12% 24% 16% 2	2280
	11th to 20th	Day	43% 3 9% 26% 18% 2	2148
	21st to end	Day	44% 4 7% 25% 18% 1	2066
October	1st to 10th	Day	45% 5% 9% 26% 13% 1	3160
	11th to 20th	Day	39% 5% 9% 23% 23% 1	3140
	21st to end	Day	45% 3 13% 24% 12% 4	3428
November	1st to 10th	Day	53% 4 11% 22% 10% 1	1664
	11th to 20th	Day	56% 4 12% 18% 9% 1	1600
	21st to end	Day	60% 4 12% 17% 6%	1600
December	1st to 10th	Day	59% 5% 10% 20% 5%	2610
	11th to 20th	Day	62% 3 9% 16% 10%	2995
	21st to end	Day	59% 2 14% 16% 9%	3982
January	1st to 10th	Night	68% 4 9% 14% 4	6349
	11th to 20th	Night	68% 4 11% 13% 4	6015
	21st to end	Night	59% 4 11% 16% 9%	6490
February	1st to 10th	Night	60% 4 11% 16% 9% 1	2600
	11th to 20th	Night	60% 3 11% 16% 8% 1	2536
	21st to end	Night	53% 4 13% 20% 10% 1	2090
March	1st to 10th	Night	65% 3 6% 12% 12% 1	4924
	11th to 20th	Night	58% 3 14% 18% 7% 1	4980
	21st to end	Night	61% 2 7% 19% 10% 1	5466
April	1st to 10th	Night	57% 3 9% 15% 14% 3	2050
	11th to 20th	Night	52% 2 10% 22% 13% 2	1775
	21st to end	Night	55% 2 8% 20% 12% 3	1710
May	1st to 10th	Night	59% 2 14% 19% 7% 1	2840
	11th to 20th	Night	58% 3 10% 22% 7% 1	2538
	21st to end	Night	52% 5% 12% 23% 8%	2750
June	1st to 10th	Night	53% 4 11% 22% 10%	1520
	11th to 20th	Night	50% 3 13% 21% 12% 1	1391
	21st to end	Night	58% 5% 11% 15% 11% 1	1330
July	1st to 10th	Night	55% 4 11% 18% 10% 1	2175
	11th to 20th	Night	53% 4 13% 19% 10% 1	2482
	21st to end	Night	47% 4 13% 23% 12% 1	2948
August	1st to 10th	Night	52% 3 12% 22% 10%	2813
	11th to 20th	Night	47% 4 16% 25% 7%	2809
	21st to end	Night	32% 4 15% 28% 21% 1	3251
September	1st to 10th	Night	39% 4 10% 28% 17% 2	1900
	11th to 20th	Night	41% 2 8% 30% 18% 2	2028
	21st to end	Night	48% 4 7% 25% 15% 2	2114
October	1st to 10th	Night	46% 4 12% 25% 13% 1	3800
	11th to 20th	Night	34% 3 11% 28% 23%	3779
	21st to end	Night	40% 4 10% 26% 19% 1	4120
November	1st to 10th	Night	47% 4 14% 22% 11% 1	2632
	11th to 20th	Night	55% 4 12% 20% 10%	2800
	21st to end	Night	55% 5% 15% 17% 7% 1	2800
December	1st to 10th	Night	55% 5% 11% 25% 4	4580
	11th to 20th	Night	54% 3 12% 19% 11% 1	5215
	21st to end	Night	59% 3 11% 17% 10% 1	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	34% 23% 29% 13% 2	400
	11th to 20th	Day	35% 21% 27% 13% 4	400
	21st to end	Day	26% 25% 33% 13% 3 1	440
February	1st to 10th	Day	34% 21% 28% 15% 2	400
	11th to 20th	Day	37% 26% 24% 12% 1	396
	21st to end	Day	33% 18% 31% 15% 2 1	358
March	1st to 10th	Day	37% 22% 29% 9% 3	500
	11th to 20th	Day	34% 25% 27% 9% 4 1	500
	21st to end	Day	37% 25% 24% 9% 5%	550
April	1st to 10th	Day	43% 23% 25% 6% 2	500
	11th to 20th	Day	32% 25% 30% 11% 3	452
	21st to end	Day	35% 19% 28% 12% 4	460
May	1st to 10th	Day	33% 25% 29% 9% 3 1	463
	11th to 20th	Day	28% 20% 30% 17% 4 1	654
	21st to end	Day	31% 16% 32% 16% 4 1	735
June	1st to 10th	Day	33% 15% 32% 17% 3	680
	11th to 20th	Day	25% 16% 35% 19% 5% 1	680
	21st to end	Day	32% 14% 30% 18% 5% 1	680
July	1st to 10th	Day	24% 11% 36% 21% 7% 1	670
	11th to 20th	Day	23% 8% 38% 22% 9% 1	668
	21st to end	Day	24% 12% 35% 22% 6% 1	561
August	1st to 10th	Day	19% 11% 37% 23% 8% 1	486
	11th to 20th	Day	20% 15% 35% 20% 9% 2	479
	21st to end	Day	20% 13% 34% 22% 9% 2	539
September	1st to 10th	Day	20% 13% 36% 23% 7% 1	490
	11th to 20th	Day	26% 15% 29% 19% 8% 3	490
	21st to end	Day	23% 17% 33% 18% 7% 2	477
October	1st to 10th	Day	23% 16% 32% 18% 9% 3	390
	11th to 20th	Day	26% 18% 28% 19% 6% 3	390
	21st to end	Day	33% 19% 27% 14% 6% 1	429
November	1st to 10th	Day	27% 18% 32% 14% 7% 1	395
	11th to 20th	Day	39% 19% 23% 14% 5% 1	400
	21st to end	Day	35% 20% 31% 10% 4 1	400
December	1st to 10th	Day	39% 19% 26% 15% 2	400
	11th to 20th	Day	44% 21% 23% 11% 2 1	400
	21st to end	Day	36% 22% 25% 13% 3 1	440
January	1st to 10th	Night	31% 20% 31% 16% 2	900
	11th to 20th	Night	31% 19% 28% 20% 3	825
	21st to end	Night	25% 21% 32% 18% 4	880
February	1st to 10th	Night	32% 18% 29% 19% 2	800
	11th to 20th	Night	31% 21% 32% 14% 2	783
	21st to end	Night	22% 18% 37% 19% 4	660
March	1st to 10th	Night	30% 19% 32% 17% 2	800
	11th to 20th	Night	27% 20% 29% 19% 5%	800
	21st to end	Night	28% 20% 32% 15% 4	880
April	1st to 10th	Night	36% 17% 31% 13% 2	650
	11th to 20th	Night	30% 19% 34% 15% 2	567
	21st to end	Night	30% 17% 30% 18% 5%	570
May	1st to 10th	Night	30% 15% 32% 19% 5%	570
	11th to 20th	Night	28% 12% 35% 21% 4	562
	21st to end	Night	24% 14% 39% 19% 5%	616
June	1st to 10th	Night	32% 8% 37% 19% 4	570
	11th to 20th	Night	23% 11% 37% 22% 6%	441
	21st to end	Night	31% 6% 34% 23% 6%	380
July	1st to 10th	Night	23% 5% 39% 25% 9%	370
	11th to 20th	Night	19% 7% 39% 27% 8%	552
	21st to end	Night	20% 6% 38% 30% 6%	623
August	1st to 10th	Night	17% 8% 35% 29% 10% 1	568
	11th to 20th	Night	20% 7% 34% 28% 10% 1	562
	21st to end	Night	17% 8% 34% 28% 12% 1	627
September	1st to 10th	Night	21% 9% 34% 26% 10%	570
	11th to 20th	Night	22% 10% 28% 26% 13% 2	698
	21st to end	Night	24% 12% 31% 22% 10% 1	760
October	1st to 10th	Night	23% 11% 32% 26% 9% 1	760
	11th to 20th	Night	24% 15% 29% 22% 9% 1	760
	21st to end	Night	30% 14% 29% 22% 5%	836
November	1st to 10th	Night	28% 13% 29% 23% 6% 1	835
	11th to 20th	Night	31% 18% 25% 20% 5%	900
	21st to end	Night	31% 20% 26% 17% 6%	900
December	1st to 10th	Night	33% 16% 29% 18% 4	900
	11th to 20th	Night	34% 22% 26% 15% 3	900
	21st to end	Night	34% 18% 27% 18% 3	990

Page generated at 2025-04-08 10:17:27. Version ac07

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