Nestor Falls
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Nestor 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	12% 10% 4 9% 5% 5% 5% 4 6% 7% 33%	138262
	Night	11% 11% 5% 11% 6% 5% 5% 4 5% 6% 29%	134438
Transparency	Day	49% 6% 13% 22% 9% 1	141712
	Night	55% 5% 12% 20% 8% 1	139079
Seeing	Day	18% 15% 35% 22% 8% 2	18518
	Night	18% 11% 33% 27% 10% 1	28442

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	7% 12% 7% 19% 7% 9% 6% 4 5% 4 19%	4124
	11th to 20th	Day	5% 14% 7% 16% 10% 8% 8% 8% 9% 4 11%	4112
	21st to end	Day	4 14% 9% 16% 7% 6% 9% 6% 7% 6% 16%	5204
February	1st to 10th	Day	7% 14% 6% 12% 7% 7% 9% 4 7% 6% 20%	1890
	11th to 20th	Day	7% 11% 5% 11% 7% 7% 6% 5% 6% 6% 29%	1844
	21st to end	Day	6% 11% 5% 14% 7% 7% 6% 4 6% 6% 28%	1557
March	1st to 10th	Day	9% 12% 3 9% 5% 4 4 4 5% 7% 38%	4855
	11th to 20th	Day	10% 10% 5% 13% 8% 5% 4 4 5% 7% 29%	5090
	21st to end	Day	14% 13% 5% 9% 6% 4 4 3 4 5% 33%	5649
April	1st to 10th	Day	14% 12% 3 8% 5% 4 4 4 6% 7% 34%	2520
	11th to 20th	Day	14% 14% 3 7% 4 4 4 4 6% 7% 32%	2647
	21st to end	Day	16% 11% 3 8% 5% 5% 5% 3 4 7% 33%	2740
May	1st to 10th	Day	12% 11% 3 6% 4 4 4 3 5% 6% 41%	8241
	11th to 20th	Day	15% 10% 3 6% 4 4 5% 3 5% 7% 37%	8222
	21st to end	Day	13% 6% 2 5% 4 3 4 3 5% 7% 48%	9395
June	1st to 10th	Day	13% 6% 3 7% 4 5% 5% 4 7% 8% 38%	3150
	11th to 20th	Day	15% 6% 3 7% 6% 5% 5% 4 6% 8% 36%	3150
	21st to end	Day	16% 7% 2 8% 5% 5% 5% 5% 7% 9% 31%	3150
July	1st to 10th	Day	8% 5% 2 6% 5% 5% 6% 4 7% 10% 42%	6800
	11th to 20th	Day	13% 6% 2 5% 4 4 4 4 6% 9% 43%	6800
	21st to end	Day	14% 7% 3 7% 5% 4 5% 3 5% 8% 40%	7158
August	1st to 10th	Day	11% 7% 2 6% 4 5% 5% 5% 6% 8% 40%	4433
	11th to 20th	Day	12% 5% 2 5% 4 4 4 4 6% 9% 46%	4171
	21st to end	Day	15% 7% 2 6% 4 4 4 4 6% 7% 41%	4623
September	1st to 10th	Day	13% 6% 3 6% 5% 5% 4 4 5% 8% 43%	2400
	11th to 20th	Day	16% 7% 3 7% 5% 4 5% 4 6% 8% 36%	2348
	21st to end	Day	20% 7% 2 7% 4 3 4 3 3 7% 39%	2120
October	1st to 10th	Day	17% 14% 4 9% 5% 4 4 3 5% 5% 30%	2000
	11th to 20th	Day	19% 17% 4 10% 4 4 4 3 5% 5% 25%	2000
	21st to end	Day	21% 19% 5% 10% 5% 4 4 2 4 6% 22%	2020
November	1st to 10th	Day	15% 18% 6% 12% 6% 5% 4 3 4 4 22%	1647
	11th to 20th	Day	13% 18% 7% 18% 7% 6% 3 2 4 3 18%	1680
	21st to end	Day	12% 18% 8% 17% 9% 6% 4 2 4 4 15%	1680
December	1st to 10th	Day	11% 16% 5% 22% 14% 7% 5% 3 3 4 9%	2558
	11th to 20th	Day	9% 18% 6% 14% 6% 5% 7% 4 5% 5% 20%	2709
	21st to end	Day	13% 18% 7% 20% 9% 5% 5% 3 4 3 12%	3575
January	1st to 10th	Night	4 12% 7% 20% 9% 7% 7% 5% 5% 5% 19%	8800
	11th to 20th	Night	6% 13% 6% 14% 11% 11% 10% 8% 7% 3 11%	8803
	21st to end	Night	6% 14% 8% 14% 7% 6% 8% 5% 8% 7% 17%	9005
February	1st to 10th	Night	7% 13% 6% 11% 8% 8% 7% 6% 6% 6% 22%	2730
	11th to 20th	Night	8% 10% 4 10% 6% 6% 6% 6% 6% 6% 32%	2663
	21st to end	Night	7% 13% 6% 12% 8% 7% 7% 5% 6% 6% 25%	2249
March	1st to 10th	Night	10% 11% 5% 10% 6% 6% 5% 4 5% 7% 32%	5250
	11th to 20th	Night	7% 12% 5% 11% 9% 9% 6% 4 6% 7% 26%	5089
	21st to end	Night	17% 15% 5% 9% 5% 4 4 3 4 5% 31%	5524
April	1st to 10th	Night	16% 11% 4 8% 5% 4 4 4 5% 5% 35%	2100
	11th to 20th	Night	15% 13% 5% 7% 5% 4 3 2 5% 6% 35%	1921
	21st to end	Night	15% 11% 4 9% 5% 5% 5% 4 5% 5% 32%	1878
May	1st to 10th	Night	14% 8% 3 5% 3 3 3 3 5% 7% 47%	4688
	11th to 20th	Night	18% 7% 2 5% 4 3 4 3 6% 6% 41%	4670
	21st to end	Night	14% 6% 2 5% 3 3 4 3 6% 8% 44%	4811
June	1st to 10th	Night	14% 5% 2 7% 4 4 4 4 6% 9% 41%	1470
	11th to 20th	Night	14% 6% 4 6% 4 4 4 5% 5% 6% 43%	1470
	21st to end	Night	15% 5% 2 6% 3 3 4 4 6% 9% 42%	1470
July	1st to 10th	Night	11% 4 2 4 4 4 4 4 6% 9% 48%	3180
	11th to 20th	Night	10% 4 1 5% 3 3 4 5% 7% 10% 47%	3180
	21st to end	Night	10% 6% 2 6% 4 4 5% 4 6% 7% 47%	3703
August	1st to 10th	Night	9% 5% 2 6% 6% 4 6% 4 6% 9% 45%	2723
	11th to 20th	Night	11% 6% 2 5% 3 3 3 3 6% 9% 49%	2888
	21st to end	Night	13% 6% 2 5% 3 4 4 4 5% 8% 46%	3283
September	1st to 10th	Night	11% 6% 2 7% 5% 4 4 3 4 7% 48%	2000
	11th to 20th	Night	16% 7% 2 6% 4 4 4 2 5% 7% 43%	2050
	21st to end	Night	18% 8% 3 7% 3 3 4 3 4 6% 41%	2260
October	1st to 10th	Night	16% 12% 3 7% 5% 4 5% 4 5% 6% 34%	2400
	11th to 20th	Night	18% 16% 4 8% 4 4 3 3 4 6% 30%	2400
	21st to end	Night	20% 15% 4 9% 6% 5% 4 4 4 5% 24%	2818
November	1st to 10th	Night	15% 18% 6% 11% 5% 4 5% 2 4 5% 24%	2871
	11th to 20th	Night	14% 17% 6% 17% 8% 4 4 3 4 4 19%	2940
	21st to end	Night	12% 17% 7% 15% 10% 6% 4 3 4 4 17%	2940
December	1st to 10th	Night	9% 19% 8% 22% 11% 8% 5% 3 2 3 9%	4848
	11th to 20th	Night	10% 14% 5% 15% 8% 8% 6% 7% 5% 5% 16%	5718
	21st to end	Night	14% 16% 7% 19% 9% 6% 5% 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	67% 4 7% 14% 7% 1	4125
	11th to 20th	Day	71% 4 7% 16% 4	4140
	21st to end	Day	66% 4 8% 16% 6%	5204
February	1st to 10th	Day	62% 5% 10% 14% 8% 1	1890
	11th to 20th	Day	53% 6% 12% 21% 8% 1	1853
	21st to end	Day	56% 5% 11% 16% 11% 1	1557
March	1st to 10th	Day	45% 4 15% 16% 14% 6%	4857
	11th to 20th	Day	53% 5% 11% 19% 10%	5090
	21st to end	Day	54% 5% 7% 21% 13% 1	5649
April	1st to 10th	Day	50% 5% 9% 21% 14% 1	2520
	11th to 20th	Day	50% 6% 12% 19% 13%	2647
	21st to end	Day	52% 5% 10% 23% 10% 1	2740
May	1st to 10th	Day	43% 6% 10% 27% 13% 1	8250
	11th to 20th	Day	45% 6% 10% 21% 16% 2	8226
	21st to end	Day	36% 4 10% 29% 18% 2	9395
June	1st to 10th	Day	42% 8% 15% 22% 12% 1	3150
	11th to 20th	Day	45% 8% 13% 24% 10%	3150
	21st to end	Day	47% 9% 16% 21% 7%	3150
July	1st to 10th	Day	34% 9% 21% 28% 7%	6727
	11th to 20th	Day	37% 6% 19% 33% 5%	6719
	21st to end	Day	43% 7% 15% 29% 6%	6953
August	1st to 10th	Day	40% 7% 16% 25% 12% 1	4418
	11th to 20th	Day	34% 7% 27% 27% 5%	4210
	21st to end	Day	41% 6% 21% 27% 5%	4622
September	1st to 10th	Day	39% 8% 15% 30% 8%	2400
	11th to 20th	Day	46% 8% 21% 21% 4	2348
	21st to end	Day	46% 6% 15% 28% 6%	2120
October	1st to 10th	Day	45% 6% 16% 25% 8%	3260
	11th to 20th	Day	51% 3 15% 18% 13%	3240
	21st to end	Day	57% 5% 17% 19% 2	3252
November	1st to 10th	Day	66% 5% 11% 13% 4 1	1647
	11th to 20th	Day	71% 4 10% 11% 4	1680
	21st to end	Day	73% 5% 11% 9% 2	1680
December	1st to 10th	Day	80% 6% 7% 6% 2	2558
	11th to 20th	Day	67% 3 9% 13% 8%	2710
	21st to end	Day	76% 4 6% 11% 3	3575
January	1st to 10th	Night	67% 4 8% 13% 8% 1	8800
	11th to 20th	Night	73% 4 6% 13% 4	8850
	21st to end	Night	65% 3 8% 18% 6%	9005
February	1st to 10th	Night	59% 6% 12% 14% 8% 1	2730
	11th to 20th	Night	50% 5% 14% 21% 9% 1	2664
	21st to end	Night	58% 6% 12% 17% 8%	2249
March	1st to 10th	Night	50% 5% 13% 15% 13% 4	5261
	11th to 20th	Night	55% 6% 13% 15% 9%	5090
	21st to end	Night	57% 4 6% 18% 14% 1	5524
April	1st to 10th	Night	49% 6% 9% 19% 16% 1	2100
	11th to 20th	Night	50% 4 10% 21% 14% 2	1921
	21st to end	Night	51% 6% 9% 21% 12% 1	1878
May	1st to 10th	Night	38% 4 9% 33% 17% 1	4695
	11th to 20th	Night	43% 5% 12% 22% 17% 1	4671
	21st to end	Night	37% 6% 9% 28% 17% 3	4812
June	1st to 10th	Night	39% 7% 16% 23% 14%	1470
	11th to 20th	Night	40% 8% 11% 26% 14% 1	1470
	21st to end	Night	39% 8% 18% 26% 8% 1	1470
July	1st to 10th	Night	32% 9% 21% 28% 9% 1	3145
	11th to 20th	Night	31% 7% 21% 33% 8%	3138
	21st to end	Night	35% 7% 17% 33% 8%	3595
August	1st to 10th	Night	35% 5% 17% 32% 9% 1	2714
	11th to 20th	Night	32% 7% 23% 32% 6%	2915
	21st to end	Night	38% 6% 21% 28% 7%	3283
September	1st to 10th	Night	37% 6% 16% 31% 10%	2000
	11th to 20th	Night	40% 7% 20% 26% 7%	2050
	21st to end	Night	44% 6% 14% 29% 6%	2260
October	1st to 10th	Night	42% 5% 13% 32% 8%	3920
	11th to 20th	Night	49% 4 15% 25% 8%	3899
	21st to end	Night	57% 5% 13% 20% 5%	4540
November	1st to 10th	Night	64% 6% 11% 14% 5% 1	2871
	11th to 20th	Night	70% 6% 9% 11% 4	2940
	21st to end	Night	70% 7% 12% 8% 3	2940
December	1st to 10th	Night	82% 4 7% 6% 1	4848
	11th to 20th	Night	67% 5% 9% 11% 8%	5716
	21st to end	Night	76% 4 6% 11% 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	13% 22% 36% 21% 8% 1	330
	11th to 20th	Day	15% 13% 44% 24% 4	330
	21st to end	Day	16% 10% 43% 22% 7% 1	363
February	1st to 10th	Day	18% 17% 41% 18% 5% 1	330
	11th to 20th	Day	12% 21% 38% 18% 8% 3	330
	21st to end	Day	17% 22% 42% 14% 3 1	273
March	1st to 10th	Day	18% 19% 38% 18% 8% 1	330
	11th to 20th	Day	17% 21% 36% 17% 7% 1	330
	21st to end	Day	16% 21% 38% 18% 6% 1	389
April	1st to 10th	Day	22% 16% 33% 21% 6%	540
	11th to 20th	Day	25% 18% 30% 21% 5% 1	685
	21st to end	Day	21% 16% 33% 22% 7% 1	750
May	1st to 10th	Day	23% 16% 36% 18% 6% 2	753
	11th to 20th	Day	21% 18% 34% 18% 8% 2	775
	21st to end	Day	20% 13% 35% 23% 7% 1	844
June	1st to 10th	Day	16% 15% 36% 21% 8% 3	780
	11th to 20th	Day	18% 17% 38% 18% 7% 1	780
	21st to end	Day	18% 11% 33% 24% 10% 3	780
July	1st to 10th	Day	10% 12% 32% 28% 14% 4	722
	11th to 20th	Day	16% 12% 30% 27% 12% 4	718
	21st to end	Day	12% 10% 33% 25% 14% 5%	794
August	1st to 10th	Day	12% 9% 33% 30% 14% 3	726
	11th to 20th	Day	13% 8% 31% 27% 15% 5%	715
	21st to end	Day	17% 9% 32% 28% 12% 2	777
September	1st to 10th	Day	16% 10% 32% 29% 10% 2	530
	11th to 20th	Day	20% 14% 35% 23% 7% 1	478
	21st to end	Day	25% 15% 32% 19% 7% 1	330
October	1st to 10th	Day	24% 17% 35% 18% 6%	330
	11th to 20th	Day	26% 20% 33% 18% 3	330
	21st to end	Day	31% 20% 31% 15% 3 1	363
November	1st to 10th	Day	23% 21% 35% 18% 4	330
	11th to 20th	Day	26% 21% 35% 15% 3 1	330
	21st to end	Day	25% 21% 40% 10% 4	330
December	1st to 10th	Day	21% 15% 38% 22% 4 2	330
	11th to 20th	Day	22% 21% 38% 17% 3	330
	21st to end	Day	19% 14% 40% 17% 8% 1	363
January	1st to 10th	Night	13% 16% 37% 24% 9% 1	1050
	11th to 20th	Night	17% 11% 39% 26% 6% 1	1050
	21st to end	Night	15% 13% 38% 26% 7% 1	1155
February	1st to 10th	Night	14% 12% 36% 30% 7% 1	1050
	11th to 20th	Night	14% 13% 36% 25% 10% 2	1029
	21st to end	Night	13% 12% 41% 22% 10% 2	865
March	1st to 10th	Night	15% 15% 36% 25% 9% 1	740
	11th to 20th	Night	15% 14% 39% 25% 7% 1	630
	21st to end	Night	21% 11% 32% 22% 11% 3	693
April	1st to 10th	Night	20% 12% 30% 29% 8% 1	630
	11th to 20th	Night	22% 12% 31% 26% 9%	623
	21st to end	Night	20% 11% 29% 29% 10%	630
May	1st to 10th	Night	22% 10% 31% 30% 7% 1	630
	11th to 20th	Night	21% 11% 35% 21% 10% 1	621
	21st to end	Night	19% 8% 30% 32% 11%	683
June	1st to 10th	Night	16% 9% 31% 31% 12%	630
	11th to 20th	Night	18% 9% 31% 30% 12%	630
	21st to end	Night	17% 6% 26% 33% 17% 1	630
July	1st to 10th	Night	9% 5% 27% 37% 20% 1	585
	11th to 20th	Night	12% 8% 26% 36% 18% 1	582
	21st to end	Night	9% 5% 25% 38% 21% 2	657
August	1st to 10th	Night	9% 6% 27% 39% 18% 2	597
	11th to 20th	Night	14% 5% 23% 34% 20% 4	594
	21st to end	Night	16% 6% 28% 31% 18% 1	660
September	1st to 10th	Night	15% 6% 31% 33% 15% 1	600
	11th to 20th	Night	19% 10% 29% 30% 12% 1	600
	21st to end	Night	21% 12% 30% 24% 12% 1	660
October	1st to 10th	Night	23% 13% 33% 26% 4 1	800
	11th to 20th	Night	28% 13% 30% 23% 7%	800
	21st to end	Night	29% 12% 34% 19% 5%	958
November	1st to 10th	Night	24% 14% 33% 23% 5% 1	1025
	11th to 20th	Night	24% 13% 34% 23% 5% 1	1050
	21st to end	Night	21% 19% 37% 18% 4	1050
December	1st to 10th	Night	16% 13% 37% 25% 7% 1	1050
	11th to 20th	Night	19% 14% 39% 22% 5% 1	1050
	21st to end	Night	21% 12% 34% 24% 7% 1	1155

Page generated at 2026-06-28 01:10:49. Version ac07

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