Ear Falls
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Ear Falls clear sky chart from 2005-11-06 to 2026-07-01.

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% 11% 4 10% 6% 5% 5% 4 5% 7% 31%	138180
	Night	12% 12% 5% 11% 6% 6% 6% 4 5% 5% 27%	134490
Transparency	Day	52% 5% 12% 22% 9% 1	141561
	Night	57% 4 11% 19% 8% 1	139200
Seeing	Day	20% 13% 33% 23% 9% 2	18594
	Night	20% 9% 30% 28% 11% 1	28528

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	6% 14% 9% 20% 9% 8% 8% 4 4 4 15%	4124
	11th to 20th	Day	5% 14% 7% 18% 9% 7% 7% 7% 9% 5% 11%	4112
	21st to end	Day	5% 14% 7% 17% 7% 6% 9% 6% 7% 5% 17%	4789
February	1st to 10th	Day	7% 15% 4 12% 8% 8% 9% 6% 6% 6% 19%	1890
	11th to 20th	Day	8% 12% 4 9% 7% 8% 7% 6% 5% 7% 25%	1844
	21st to end	Day	5% 13% 6% 15% 9% 7% 5% 5% 6% 6% 23%	1557
March	1st to 10th	Day	9% 12% 5% 14% 6% 3 4 3 4 6% 36%	4752
	11th to 20th	Day	10% 11% 5% 13% 9% 6% 5% 3 4 5% 28%	5090
	21st to end	Day	11% 15% 6% 11% 5% 6% 4 3 5% 5% 29%	5720
April	1st to 10th	Day	10% 13% 4 10% 5% 6% 4 3 5% 6% 34%	2520
	11th to 20th	Day	15% 11% 4 10% 6% 4 4 3 5% 6% 33%	2651
	21st to end	Day	12% 10% 4 8% 6% 5% 5% 4 6% 6% 33%	2818
May	1st to 10th	Day	11% 12% 4 6% 4 5% 4 4 5% 7% 37%	8241
	11th to 20th	Day	20% 10% 3 7% 4 4 4 3 5% 7% 33%	8222
	21st to end	Day	15% 8% 2 5% 3 3 4 3 5% 7% 46%	9603
June	1st to 10th	Day	18% 8% 3 6% 5% 5% 6% 4 7% 7% 32%	3150
	11th to 20th	Day	17% 9% 3 6% 5% 5% 5% 4 7% 8% 31%	3150
	21st to end	Day	16% 7% 2 7% 5% 6% 5% 6% 7% 8% 31%	3150
July	1st to 10th	Day	11% 6% 2 7% 5% 5% 5% 4 6% 8% 41%	6800
	11th to 20th	Day	14% 6% 2 6% 5% 5% 5% 4 7% 8% 39%	6800
	21st to end	Day	12% 5% 2 6% 4 5% 5% 4 5% 8% 42%	7286
August	1st to 10th	Day	17% 5% 2 6% 4 4 4 4 6% 8% 39%	4563
	11th to 20th	Day	10% 4 2 6% 3 4 5% 5% 8% 9% 45%	4202
	21st to end	Day	16% 7% 2 7% 4 4 5% 4 6% 9% 35%	4626
September	1st to 10th	Day	16% 7% 2 8% 5% 5% 5% 4 6% 6% 37%	2400
	11th to 20th	Day	22% 9% 3 7% 5% 5% 5% 4 5% 6% 29%	2385
	21st to end	Day	19% 11% 3 6% 5% 3 4 4 4 6% 35%	2096
October	1st to 10th	Day	21% 16% 4 8% 4 5% 3 4 4 6% 26%	2000
	11th to 20th	Day	19% 19% 5% 9% 5% 4 4 3 4 6% 22%	2000
	21st to end	Day	21% 21% 7% 10% 6% 4 3 3 4 5% 17%	1939
November	1st to 10th	Day	15% 19% 6% 13% 6% 5% 4 3 3 5% 19%	1647
	11th to 20th	Day	14% 21% 8% 14% 8% 6% 5% 3 2 4 14%	1680
	21st to end	Day	14% 19% 6% 20% 9% 5% 4 3 4 4 12%	1680
December	1st to 10th	Day	13% 17% 6% 18% 12% 9% 5% 3 4 4 10%	2409
	11th to 20th	Day	9% 15% 6% 16% 8% 6% 8% 5% 5% 5% 17%	2709
	21st to end	Day	13% 18% 8% 18% 7% 6% 5% 4 5% 6% 11%	3575
January	1st to 10th	Night	5% 16% 7% 19% 9% 8% 6% 4 5% 5% 17%	8800
	11th to 20th	Night	6% 13% 7% 17% 10% 9% 9% 8% 7% 3 11%	8803
	21st to end	Night	5% 15% 7% 16% 8% 7% 8% 6% 8% 6% 14%	9420
February	1st to 10th	Night	7% 14% 6% 11% 7% 7% 10% 7% 6% 5% 20%	2730
	11th to 20th	Night	7% 12% 4 9% 6% 7% 8% 7% 6% 6% 27%	2663
	21st to end	Night	5% 12% 7% 12% 8% 7% 6% 5% 6% 6% 25%	2249
March	1st to 10th	Night	10% 13% 5% 11% 7% 5% 5% 3 5% 5% 30%	5337
	11th to 20th	Night	9% 13% 6% 11% 9% 7% 6% 3 4 6% 27%	5089
	21st to end	Night	13% 16% 5% 9% 5% 5% 4 3 5% 5% 31%	5453
April	1st to 10th	Night	12% 11% 3 8% 5% 4 4 3 5% 5% 40%	2100
	11th to 20th	Night	13% 11% 4 7% 6% 5% 5% 3 4 5% 36%	1915
	21st to end	Night	13% 12% 3 7% 5% 4 4 3 4 5% 39%	1801
May	1st to 10th	Night	11% 10% 4 7% 5% 5% 4 4 5% 5% 41%	4688
	11th to 20th	Night	22% 8% 3 7% 4 3 4 3 5% 6% 36%	4670
	21st to end	Night	17% 6% 2 4 3 3 4 3 4 6% 47%	4591
June	1st to 10th	Night	18% 8% 3 6% 4 5% 4 3 7% 9% 35%	1470
	11th to 20th	Night	15% 8% 3 7% 4 4 4 4 6% 8% 38%	1470
	21st to end	Night	14% 6% 2 5% 4 5% 4 4 7% 8% 42%	1470
July	1st to 10th	Night	11% 5% 2 7% 4 4 4 4 6% 7% 47%	3180
	11th to 20th	Night	13% 4 2 6% 4 4 5% 3 6% 8% 45%	3180
	21st to end	Night	13% 6% 2 6% 4 4 4 4 5% 7% 46%	3588
August	1st to 10th	Night	15% 6% 2 7% 4 5% 4 3 6% 7% 41%	2597
	11th to 20th	Night	10% 5% 2 5% 3 4 4 4 6% 9% 48%	2854
	21st to end	Night	16% 7% 2 7% 4 4 4 4 5% 8% 40%	3281
September	1st to 10th	Night	16% 7% 2 7% 3 4 3 3 4 7% 44%	2000
	11th to 20th	Night	23% 8% 2 6% 4 3 4 3 4 6% 37%	2013
	21st to end	Night	19% 9% 2 6% 4 3 4 3 5% 7% 39%	2283
October	1st to 10th	Night	17% 13% 4 8% 5% 4 5% 4 5% 6% 30%	2400
	11th to 20th	Night	21% 16% 3 8% 4 4 4 3 4 6% 27%	2400
	21st to end	Night	20% 18% 5% 11% 5% 5% 4 3 4 5% 19%	2897
November	1st to 10th	Night	15% 18% 6% 12% 6% 4 4 3 4 5% 23%	2871
	11th to 20th	Night	17% 17% 6% 15% 8% 6% 4 3 4 3 16%	2940
	21st to end	Night	14% 20% 8% 17% 9% 6% 4 4 3 4 12%	2940
December	1st to 10th	Night	10% 21% 10% 19% 11% 7% 5% 3 3 3 8%	4984
	11th to 20th	Night	10% 14% 5% 14% 8% 8% 9% 6% 5% 5% 16%	5718
	21st to end	Night	10% 17% 9% 19% 9% 7% 6% 3 4 4 13%	7645

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	74% 2 5% 11% 6% 1	4125
	11th to 20th	Day	70% 2 7% 17% 4	4140
	21st to end	Day	66% 3 7% 15% 9%	4789
February	1st to 10th	Day	63% 4 10% 14% 9%	1890
	11th to 20th	Day	56% 4 10% 22% 8%	1853
	21st to end	Day	59% 4 8% 19% 9% 1	1557
March	1st to 10th	Day	51% 3 11% 16% 14% 5%	4754
	11th to 20th	Day	58% 4 7% 19% 11% 1	5090
	21st to end	Day	57% 3 6% 20% 13% 1	5720
April	1st to 10th	Day	51% 3 9% 20% 14% 3	2520
	11th to 20th	Day	52% 3 9% 23% 12% 1	2651
	21st to end	Day	50% 4 10% 24% 11% 2	2818
May	1st to 10th	Day	45% 5% 9% 28% 13%	8250
	11th to 20th	Day	51% 4 11% 21% 12% 1	8226
	21st to end	Day	38% 4 9% 29% 18% 2	9603
June	1st to 10th	Day	49% 7% 11% 22% 11%	3150
	11th to 20th	Day	49% 6% 12% 21% 12% 1	3150
	21st to end	Day	47% 7% 15% 23% 8%	3150
July	1st to 10th	Day	39% 6% 16% 29% 8%	6727
	11th to 20th	Day	40% 7% 17% 31% 4	6719
	21st to end	Day	39% 6% 17% 31% 7%	7075
August	1st to 10th	Day	43% 5% 14% 30% 8%	4548
	11th to 20th	Day	33% 7% 25% 33% 3	4242
	21st to end	Day	43% 6% 20% 27% 4	4625
September	1st to 10th	Day	46% 6% 15% 27% 6%	2400
	11th to 20th	Day	56% 6% 15% 21% 3	2385
	21st to end	Day	50% 5% 16% 23% 6%	2096
October	1st to 10th	Day	51% 4 15% 22% 7%	3260
	11th to 20th	Day	56% 3 15% 18% 8%	3240
	21st to end	Day	59% 5% 20% 14% 2	3107
November	1st to 10th	Day	68% 4 11% 11% 5% 1	1647
	11th to 20th	Day	76% 3 8% 10% 3	1680
	21st to end	Day	77% 3 10% 8% 2	1680
December	1st to 10th	Day	79% 3 10% 7% 2	2409
	11th to 20th	Day	68% 4 8% 12% 8%	2710
	21st to end	Day	74% 3 6% 13% 4	3575
January	1st to 10th	Night	70% 3 7% 11% 9%	8800
	11th to 20th	Night	74% 3 7% 12% 4	8850
	21st to end	Night	68% 3 7% 16% 5%	9420
February	1st to 10th	Night	62% 5% 9% 16% 8%	2730
	11th to 20th	Night	54% 5% 10% 23% 7%	2664
	21st to end	Night	57% 4 9% 20% 9% 1	2249
March	1st to 10th	Night	56% 4 7% 14% 16% 4	5348
	11th to 20th	Night	58% 4 9% 17% 10% 1	5090
	21st to end	Night	55% 3 8% 18% 15% 1	5453
April	1st to 10th	Night	47% 2 7% 23% 18% 3	2100
	11th to 20th	Night	50% 3 8% 20% 17% 2	1915
	21st to end	Night	48% 4 7% 24% 14% 2	1801
May	1st to 10th	Night	44% 5% 6% 30% 14%	4695
	11th to 20th	Night	49% 5% 11% 22% 12% 1	4671
	21st to end	Night	39% 4 9% 28% 18% 2	4592
June	1st to 10th	Night	46% 6% 14% 20% 14% 1	1470
	11th to 20th	Night	43% 5% 13% 25% 14% 1	1470
	21st to end	Night	38% 7% 17% 29% 10% 1	1470
July	1st to 10th	Night	35% 7% 17% 31% 10%	3145
	11th to 20th	Night	36% 5% 19% 34% 5% 1	3138
	21st to end	Night	37% 6% 17% 32% 9%	3485
August	1st to 10th	Night	42% 5% 13% 31% 9% 1	2588
	11th to 20th	Night	32% 6% 22% 35% 5%	2880
	21st to end	Night	43% 5% 21% 26% 5%	3281
September	1st to 10th	Night	40% 5% 16% 30% 9%	2000
	11th to 20th	Night	48% 6% 17% 24% 5%	2013
	21st to end	Night	45% 5% 18% 26% 6%	2283
October	1st to 10th	Night	50% 5% 16% 23% 6%	3920
	11th to 20th	Night	53% 4 17% 21% 6%	3899
	21st to end	Night	59% 4 18% 16% 2	4684
November	1st to 10th	Night	66% 3 11% 16% 4	2871
	11th to 20th	Night	73% 4 9% 12% 3	2940
	21st to end	Night	78% 3 9% 8% 2	2940
December	1st to 10th	Night	84% 2 7% 5% 2	4984
	11th to 20th	Night	69% 4 9% 11% 7%	5716
	21st to end	Night	76% 3 5% 13% 3	7645

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	16% 10% 41% 23% 9% 1	330
	11th to 20th	Day	13% 9% 38% 28% 10% 1	330
	21st to end	Day	14% 9% 40% 26% 10% 1	363
February	1st to 10th	Day	21% 13% 43% 16% 6% 2	330
	11th to 20th	Day	12% 17% 33% 23% 12% 2	330
	21st to end	Day	12% 18% 44% 18% 7% 1	273
March	1st to 10th	Day	18% 10% 43% 21% 7% 1	330
	11th to 20th	Day	15% 18% 42% 20% 5%	330
	21st to end	Day	20% 14% 37% 20% 8% 1	421
April	1st to 10th	Day	16% 14% 35% 24% 9% 1	540
	11th to 20th	Day	23% 13% 31% 24% 8% 1	689
	21st to end	Day	18% 13% 35% 24% 9% 1	750
May	1st to 10th	Day	20% 15% 34% 24% 6% 1	753
	11th to 20th	Day	25% 14% 31% 21% 7% 2	775
	21st to end	Day	23% 10% 32% 25% 9% 2	844
June	1st to 10th	Day	22% 14% 32% 22% 9% 2	780
	11th to 20th	Day	21% 15% 34% 20% 8% 2	780
	21st to end	Day	18% 12% 28% 27% 12% 3	780
July	1st to 10th	Day	12% 13% 32% 26% 13% 4	722
	11th to 20th	Day	18% 12% 29% 24% 14% 3	718
	21st to end	Day	12% 7% 31% 30% 15% 5%	794
August	1st to 10th	Day	16% 11% 28% 29% 12% 4	726
	11th to 20th	Day	15% 9% 28% 29% 16% 4	715
	21st to end	Day	21% 8% 29% 27% 13% 1	780
September	1st to 10th	Day	20% 11% 30% 27% 11% 1	530
	11th to 20th	Day	28% 11% 32% 23% 6% 1	515
	21st to end	Day	26% 13% 36% 18% 5% 1	330
October	1st to 10th	Day	33% 12% 28% 20% 8%	330
	11th to 20th	Day	27% 17% 33% 18% 6%	330
	21st to end	Day	34% 15% 31% 16% 4	363
November	1st to 10th	Day	25% 19% 33% 16% 6% 1	330
	11th to 20th	Day	27% 17% 35% 15% 5% 1	330
	21st to end	Day	24% 21% 40% 12% 4	330
December	1st to 10th	Day	17% 15% 36% 23% 7% 2	330
	11th to 20th	Day	21% 12% 40% 23% 4 1	330
	21st to end	Day	19% 11% 34% 22% 12% 2	363
January	1st to 10th	Night	16% 12% 34% 28% 9% 2	1050
	11th to 20th	Night	18% 8% 34% 30% 8% 1	1050
	21st to end	Night	16% 8% 36% 30% 8% 1	1155
February	1st to 10th	Night	14% 11% 33% 31% 10% 1	1050
	11th to 20th	Night	14% 10% 32% 29% 14% 1	1029
	21st to end	Night	12% 11% 33% 30% 12% 2	865
March	1st to 10th	Night	17% 12% 32% 28% 10% 1	786
	11th to 20th	Night	17% 13% 35% 24% 10% 1	630
	21st to end	Night	20% 9% 30% 27% 11% 4	693
April	1st to 10th	Night	18% 10% 26% 36% 9%	630
	11th to 20th	Night	19% 9% 31% 28% 13% 1	623
	21st to end	Night	20% 9% 32% 27% 10% 1	630
May	1st to 10th	Night	21% 9% 33% 27% 10% 1	630
	11th to 20th	Night	27% 7% 26% 29% 11% 1	621
	21st to end	Night	25% 7% 27% 29% 11%	683
June	1st to 10th	Night	24% 6% 25% 31% 13% 1	630
	11th to 20th	Night	19% 7% 31% 31% 12% 1	630
	21st to end	Night	17% 6% 22% 37% 17% 1	630
July	1st to 10th	Night	10% 6% 30% 36% 16% 1	585
	11th to 20th	Night	14% 5% 29% 32% 18% 1	582
	21st to end	Night	10% 6% 25% 35% 21% 3	657
August	1st to 10th	Night	15% 4 27% 35% 19% 1	597
	11th to 20th	Night	16% 5% 23% 33% 21% 3	594
	21st to end	Night	20% 6% 24% 33% 17% 1	660
September	1st to 10th	Night	21% 7% 26% 30% 15% 2	600
	11th to 20th	Night	28% 7% 24% 29% 12% 2	600
	21st to end	Night	24% 8% 28% 27% 12% 1	683
October	1st to 10th	Night	27% 10% 30% 26% 8%	800
	11th to 20th	Night	32% 9% 26% 22% 10% 1	800
	21st to end	Night	29% 11% 29% 23% 7% 1	975
November	1st to 10th	Night	24% 13% 30% 22% 9% 2	1025
	11th to 20th	Night	27% 10% 32% 22% 8% 1	1050
	21st to end	Night	26% 16% 31% 22% 4 1	1050
December	1st to 10th	Night	15% 11% 37% 26% 9% 1	1050
	11th to 20th	Night	19% 12% 35% 25% 7% 1	1050
	21st to end	Night	20% 10% 30% 28% 10% 2	1155

Page generated at 2026-06-28 01:10:44. Version ac07

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