Scenic Vista Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Scenic Vista Park clear sky chart from 2005-11-06 to 2026-02-01.

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	15% 11% 4 9% 5% 5% 5% 4 5% 7% 30%	127086
	Night	16% 12% 4 9% 5% 4 4 3 5% 6% 31%	124895
Transparency	Day	51% 7% 11% 20% 11% 1	130705
	Night	52% 6% 11% 19% 11% 2	129345
Seeing	Day	22% 16% 28% 19% 11% 4	16194
	Night	22% 13% 27% 25% 12% 1	26073

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	15% 22% 6% 21% 5% 3 4 2 3 4 14%	4146
	11th to 20th	Day	12% 22% 10% 16% 8% 6% 3 2 3 4 14%	4150
	21st to end	Day	20% 19% 7% 12% 7% 6% 4 3 4 4 14%	4565
February	1st to 10th	Day	17% 19% 6% 11% 7% 5% 3 3 4 4 23%	1800
	11th to 20th	Day	16% 16% 7% 13% 6% 4 4 3 4 6% 21%	1771
	21st to end	Day	18% 15% 5% 10% 5% 4 4 4 5% 6% 25%	1650
March	1st to 10th	Day	17% 14% 6% 12% 4 4 3 3 5% 5% 28%	4925
	11th to 20th	Day	12% 9% 4 9% 6% 5% 5% 3 5% 5% 37%	4980
	21st to end	Day	19% 11% 3 10% 5% 4 4 3 5% 6% 29%	5465
April	1st to 10th	Day	15% 14% 3 8% 5% 4 4 4 5% 7% 30%	2270
	11th to 20th	Day	17% 12% 3 8% 4 4 4 4 5% 6% 33%	2472
	21st to end	Day	19% 11% 3 7% 5% 4 4 3 5% 6% 33%	2600
May	1st to 10th	Day	20% 10% 3 8% 5% 5% 5% 4 5% 6% 27%	5862
	11th to 20th	Day	18% 9% 3 7% 5% 5% 5% 4 6% 8% 30%	5861
	21st to end	Day	18% 7% 3 7% 5% 5% 5% 4 6% 8% 32%	6634
June	1st to 10th	Day	14% 8% 3 7% 5% 5% 5% 4 6% 9% 35%	2800
	11th to 20th	Day	13% 8% 3 7% 6% 4 5% 4 6% 9% 34%	2800
	21st to end	Day	12% 6% 2 6% 5% 5% 5% 5% 7% 10% 37%	2800
July	1st to 10th	Day	8% 6% 3 7% 5% 5% 5% 4 7% 10% 41%	5977
	11th to 20th	Day	10% 6% 3 8% 6% 6% 6% 5% 7% 10% 34%	5900
	21st to end	Day	11% 6% 3 7% 5% 5% 5% 5% 7% 9% 39%	6424
August	1st to 10th	Day	13% 7% 3 8% 6% 6% 6% 4 7% 9% 31%	4234
	11th to 20th	Day	11% 6% 2 7% 6% 6% 7% 5% 7% 9% 33%	4174
	21st to end	Day	7% 5% 2 7% 5% 7% 5% 5% 7% 9% 40%	4520
September	1st to 10th	Day	13% 6% 3 6% 4 4 4 3 5% 7% 46%	2347
	11th to 20th	Day	9% 6% 2 5% 4 4 5% 5% 6% 9% 44%	2200
	21st to end	Day	19% 8% 3 7% 5% 3 4 4 5% 6% 35%	2200
October	1st to 10th	Day	14% 7% 2 6% 4 4 4 4 5% 8% 41%	2033
	11th to 20th	Day	18% 9% 3 7% 5% 5% 4 4 5% 6% 34%	2000
	21st to end	Day	22% 11% 4 7% 5% 4 4 3 5% 6% 31%	2200
November	1st to 10th	Day	11% 9% 4 7% 5% 5% 4 4 5% 6% 41%	1912
	11th to 20th	Day	17% 15% 5% 8% 5% 4 4 3 4 6% 29%	1813
	21st to end	Day	17% 17% 7% 9% 4 3 4 3 6% 6% 23%	1680
December	1st to 10th	Day	20% 15% 6% 15% 5% 4 4 3 4 4 20%	2680
	11th to 20th	Day	23% 18% 6% 11% 4 3 3 2 4 5% 21%	3070
	21st to end	Day	23% 23% 6% 12% 5% 4 3 3 4 5% 12%	4171
January	1st to 10th	Night	14% 19% 7% 23% 7% 4 3 3 3 4 13%	6019
	11th to 20th	Night	13% 19% 8% 17% 9% 6% 4 3 3 4 13%	6030
	21st to end	Night	21% 18% 7% 13% 7% 3 4 2 3 4 18%	6633
February	1st to 10th	Night	20% 15% 5% 12% 6% 4 4 3 4 5% 22%	2601
	11th to 20th	Night	18% 14% 6% 13% 6% 5% 4 3 4 5% 22%	2513
	21st to end	Night	19% 14% 5% 13% 6% 4 4 4 4 4 24%	1980
March	1st to 10th	Night	21% 13% 5% 9% 5% 4 3 2 3 4 31%	4928
	11th to 20th	Night	13% 11% 5% 8% 4 4 4 3 5% 6% 38%	4980
	21st to end	Night	18% 11% 3 8% 5% 4 4 3 4 5% 34%	5467
April	1st to 10th	Night	18% 13% 3 6% 5% 4 5% 3 5% 7% 31%	2129
	11th to 20th	Night	15% 10% 3 7% 6% 4 4 4 6% 7% 34%	1894
	21st to end	Night	16% 10% 2 8% 5% 4 3 4 6% 8% 36%	1800
May	1st to 10th	Night	25% 11% 3 7% 5% 4 4 3 5% 7% 25%	4033
	11th to 20th	Night	16% 10% 3 7% 4 3 4 3 5% 8% 36%	4032
	21st to end	Night	17% 7% 2 5% 4 4 4 4 6% 9% 37%	4202
June	1st to 10th	Night	9% 7% 3 7% 5% 5% 5% 4 6% 8% 43%	1600
	11th to 20th	Night	12% 5% 3 6% 5% 4 4 4 6% 11% 42%	1600
	21st to end	Night	8% 6% 2 6% 4 5% 6% 5% 6% 8% 43%	1600
July	1st to 10th	Night	10% 7% 3 7% 4 4 5% 4 5% 8% 42%	3961
	11th to 20th	Night	10% 6% 3 6% 5% 5% 5% 5% 8% 10% 38%	4057
	21st to end	Night	7% 6% 3 7% 5% 5% 5% 4 6% 8% 44%	4427
August	1st to 10th	Night	12% 9% 3 8% 4 5% 5% 4 6% 8% 38%	2915
	11th to 20th	Night	12% 8% 3 7% 4 3 4 4 6% 7% 44%	2875
	21st to end	Night	7% 4 3 7% 5% 5% 5% 5% 7% 9% 44%	3345
September	1st to 10th	Night	13% 5% 2 6% 3 3 4 4 4 6% 51%	2050
	11th to 20th	Night	9% 4 2 5% 4 3 3 4 6% 8% 53%	2200
	21st to end	Night	17% 8% 3 6% 4 4 3 4 5% 6% 41%	2200
October	1st to 10th	Night	13% 6% 2 6% 4 4 3 3 5% 8% 46%	2365
	11th to 20th	Night	15% 8% 3 7% 5% 5% 5% 4 5% 8% 37%	2400
	21st to end	Night	22% 10% 3 6% 4 3 3 3 4 7% 36%	2640
November	1st to 10th	Night	13% 8% 3 6% 4 4 4 3 6% 6% 43%	2601
	11th to 20th	Night	17% 13% 4 9% 5% 4 4 3 5% 6% 31%	2804
	21st to end	Night	20% 15% 5% 8% 5% 3 4 3 5% 6% 26%	2940
December	1st to 10th	Night	16% 17% 7% 13% 6% 5% 4 3 4 5% 18%	4720
	11th to 20th	Night	19% 21% 7% 10% 4 3 3 3 4 5% 20%	5345
	21st to end	Night	23% 20% 6% 11% 5% 3 4 3 4 5% 15%	7009

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	73% 5% 9% 9% 4	4147
	11th to 20th	Day	75% 4 7% 9% 4 1	4150
	21st to end	Day	73% 5% 8% 10% 4	4565
February	1st to 10th	Day	66% 5% 9% 13% 7% 1	1800
	11th to 20th	Day	64% 5% 9% 15% 7%	1780
	21st to end	Day	60% 5% 11% 16% 7% 1	1650
March	1st to 10th	Day	57% 5% 10% 21% 6% 1	4925
	11th to 20th	Day	45% 7% 12% 25% 9% 2	4980
	21st to end	Day	54% 5% 9% 18% 13% 1	5465
April	1st to 10th	Day	52% 7% 11% 17% 11% 1	2270
	11th to 20th	Day	50% 7% 11% 17% 13% 2	2472
	21st to end	Day	51% 7% 10% 20% 10% 2	2600
May	1st to 10th	Day	54% 8% 10% 16% 9% 3	5897
	11th to 20th	Day	50% 8% 11% 20% 10% 1	5865
	21st to end	Day	46% 9% 12% 20% 11% 3	6649
June	1st to 10th	Day	44% 8% 14% 21% 12% 1	2800
	11th to 20th	Day	45% 8% 13% 21% 12% 1	2800
	21st to end	Day	40% 9% 13% 24% 14% 1	2800
July	1st to 10th	Day	37% 8% 13% 25% 15% 2	5912
	11th to 20th	Day	41% 9% 13% 24% 12% 1	5831
	21st to end	Day	39% 8% 12% 22% 19% 1	6240
August	1st to 10th	Day	46% 9% 14% 21% 10%	4221
	11th to 20th	Day	41% 8% 13% 28% 9% 1	4213
	21st to end	Day	36% 9% 14% 29% 11% 2	4520
September	1st to 10th	Day	38% 7% 11% 22% 19% 3	2347
	11th to 20th	Day	34% 7% 16% 25% 16% 1	2200
	21st to end	Day	49% 7% 10% 21% 13% 1	2200
October	1st to 10th	Day	31% 6% 11% 29% 21% 1	3306
	11th to 20th	Day	46% 6% 10% 19% 14% 4	3240
	21st to end	Day	40% 6% 12% 26% 16% 1	3538
November	1st to 10th	Day	42% 6% 12% 22% 16% 2	1912
	11th to 20th	Day	55% 5% 10% 18% 8% 2	1813
	21st to end	Day	61% 6% 11% 15% 6% 1	1680
December	1st to 10th	Day	67% 4 13% 12% 4	2680
	11th to 20th	Day	67% 4 10% 14% 5%	3066
	21st to end	Day	75% 5% 8% 9% 3	4171
January	1st to 10th	Night	74% 5% 7% 9% 3	6019
	11th to 20th	Night	74% 5% 9% 9% 3	6030
	21st to end	Night	71% 4 8% 11% 5% 1	6633
February	1st to 10th	Night	65% 5% 10% 15% 6%	2601
	11th to 20th	Night	64% 4 10% 15% 7%	2515
	21st to end	Night	63% 6% 9% 12% 9% 1	1980
March	1st to 10th	Night	57% 4 10% 20% 9% 1	4928
	11th to 20th	Night	45% 6% 14% 24% 8% 3	4980
	21st to end	Night	51% 6% 11% 18% 14% 1	5467
April	1st to 10th	Night	52% 6% 10% 18% 13% 2	2129
	11th to 20th	Night	47% 9% 11% 16% 14% 3	1894
	21st to end	Night	45% 6% 12% 20% 15% 2	1800
May	1st to 10th	Night	58% 7% 9% 14% 9% 3	4060
	11th to 20th	Night	45% 8% 10% 23% 13% 1	4033
	21st to end	Night	41% 9% 14% 24% 11% 2	4209
June	1st to 10th	Night	37% 8% 13% 23% 16% 3	1600
	11th to 20th	Night	36% 7% 16% 23% 16% 2	1600
	21st to end	Night	35% 10% 13% 24% 17% 1	1600
July	1st to 10th	Night	39% 7% 11% 23% 18% 2	3918
	11th to 20th	Night	37% 9% 18% 24% 11% 1	4006
	21st to end	Night	36% 8% 12% 19% 24% 2	4297
August	1st to 10th	Night	43% 8% 12% 23% 12% 1	2904
	11th to 20th	Night	38% 7% 12% 26% 15% 1	2902
	21st to end	Night	33% 9% 13% 30% 13% 2	3345
September	1st to 10th	Night	33% 8% 10% 24% 20% 5%	2050
	11th to 20th	Night	28% 7% 14% 27% 22% 2	2200
	21st to end	Night	43% 6% 12% 21% 18% 1	2200
October	1st to 10th	Night	32% 5% 9% 27% 25% 2	3872
	11th to 20th	Night	38% 6% 12% 22% 14% 7%	3899
	21st to end	Night	36% 4 10% 29% 19% 2	4252
November	1st to 10th	Night	40% 6% 13% 22% 16% 3	2601
	11th to 20th	Night	53% 5% 11% 19% 9% 3	2804
	21st to end	Night	59% 5% 12% 18% 5% 1	2940
December	1st to 10th	Night	67% 5% 10% 13% 3	4720
	11th to 20th	Night	67% 4 12% 14% 3	5348
	21st to end	Night	70% 6% 10% 12% 2	7009

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% 25% 28% 10% 3	330
	11th to 20th	Day	37% 30% 28% 4 1	330
	21st to end	Day	31% 33% 28% 6% 2	363
February	1st to 10th	Day	36% 22% 33% 8% 1	300
	11th to 20th	Day	38% 27% 30% 5% 1	300
	21st to end	Day	38% 27% 28% 8%	249
March	1st to 10th	Day	27% 27% 29% 14% 3	490
	11th to 20th	Day	30% 23% 29% 12% 5% 1	500
	21st to end	Day	32% 22% 29% 14% 3 1	550
April	1st to 10th	Day	29% 23% 27% 13% 6% 1	500
	11th to 20th	Day	29% 19% 27% 15% 8% 2	492
	21st to end	Day	28% 17% 32% 16% 6% 2	500
May	1st to 10th	Day	27% 20% 28% 15% 7% 2	503
	11th to 20th	Day	22% 14% 32% 20% 8% 4	527
	21st to end	Day	18% 10% 26% 26% 14% 5%	573
June	1st to 10th	Day	15% 12% 32% 25% 12% 4	530
	11th to 20th	Day	18% 10% 28% 27% 14% 4	530
	21st to end	Day	13% 11% 31% 27% 15% 3	530
July	1st to 10th	Day	12% 7% 24% 27% 21% 10%	525
	11th to 20th	Day	10% 8% 28% 28% 18% 8%	524
	21st to end	Day	11% 6% 24% 32% 17% 9%	576
August	1st to 10th	Day	12% 6% 24% 29% 21% 8%	526
	11th to 20th	Day	15% 6% 22% 29% 20% 9%	519
	21st to end	Day	10% 5% 27% 28% 20% 10%	583
September	1st to 10th	Day	15% 10% 21% 26% 20% 9%	530
	11th to 20th	Day	10% 6% 20% 29% 23% 12%	530
	21st to end	Day	22% 12% 25% 21% 15% 5%	530
October	1st to 10th	Day	14% 10% 27% 25% 18% 5%	530
	11th to 20th	Day	22% 15% 33% 20% 9% 2	530
	21st to end	Day	30% 17% 31% 16% 6%	583
November	1st to 10th	Day	21% 22% 33% 14% 9% 2	390
	11th to 20th	Day	30% 19% 31% 13% 5% 1	289
	21st to end	Day	28% 23% 39% 9%	220
December	1st to 10th	Day	31% 28% 30% 6% 3 1	220
	11th to 20th	Day	33% 24% 31% 10% 2	220
	21st to end	Day	40% 22% 25% 11% 2	272
January	1st to 10th	Night	28% 23% 34% 12% 3	840
	11th to 20th	Night	31% 23% 30% 13% 3	840
	21st to end	Night	29% 23% 28% 17% 3	924
February	1st to 10th	Night	30% 18% 30% 19% 2	801
	11th to 20th	Night	29% 21% 35% 13% 2	783
	21st to end	Night	29% 21% 32% 16% 2	660
March	1st to 10th	Night	25% 20% 32% 20% 3	800
	11th to 20th	Night	27% 18% 27% 22% 5% 1	800
	21st to end	Night	27% 14% 34% 21% 4 1	880
April	1st to 10th	Night	26% 17% 30% 22% 5%	800
	11th to 20th	Night	23% 15% 32% 20% 9% 1	710
	21st to end	Night	21% 11% 34% 27% 7%	600
May	1st to 10th	Night	24% 9% 26% 31% 9% 1	600
	11th to 20th	Night	19% 10% 27% 29% 13% 1	591
	21st to end	Night	13% 4 24% 36% 21% 3	560
June	1st to 10th	Night	12% 6% 26% 41% 16%	400
	11th to 20th	Night	13% 6% 26% 39% 17% 1	400
	21st to end	Night	10% 4 27% 35% 24% 1	400
July	1st to 10th	Night	8% 3 18% 40% 25% 7%	540
	11th to 20th	Night	8% 3 21% 36% 28% 4	582
	21st to end	Night	11% 3 17% 38% 29% 2	657
August	1st to 10th	Night	11% 3 16% 39% 30% 2	597
	11th to 20th	Night	13% 3 13% 39% 28% 4	594
	21st to end	Night	10% 4 20% 31% 28% 6%	730
September	1st to 10th	Night	15% 5% 20% 31% 26% 4	800
	11th to 20th	Night	9% 5% 16% 37% 30% 4	800
	21st to end	Night	20% 7% 24% 26% 19% 4	800
October	1st to 10th	Night	17% 9% 22% 28% 22% 3	800
	11th to 20th	Night	20% 12% 31% 23% 12% 1	800
	21st to end	Night	26% 13% 29% 23% 8%	880
November	1st to 10th	Night	18% 15% 27% 30% 10%	820
	11th to 20th	Night	27% 18% 27% 20% 7% 1	840
	21st to end	Night	30% 16% 29% 20% 5%	840
December	1st to 10th	Night	31% 20% 28% 18% 4	840
	11th to 20th	Night	31% 19% 29% 18% 3	840
	21st to end	Night	31% 18% 31% 18% 2	924

Page generated at 2026-01-29 01:21:41. Version ac07

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