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 2024-01-14.

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	16% 10% 4 7% 6% 3 5% 5% 5% 7% 31%	74601
	Night	16% 11% 4 7% 6% 3 4 4 5% 7% 33%	75146
Transparency	Day	52% 7% 12% 18% 10% 1	74322
	Night	51% 6% 12% 19% 11% 2	74944
Seeing	Day	22% 15% 28% 20% 11% 4	13535
	Night	22% 13% 27% 25% 12% 1	23421

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	16% 18% 8% 11% 8% 4 5% 4 3 5% 18%	1706
	11th to 20th	Day	19% 21% 9% 11% 7% 3 3 3 3 5% 17%	1647
	21st to end	Day	16% 19% 9% 12% 8% 4 4 4 4 5% 16%	1782
February	1st to 10th	Day	18% 17% 7% 10% 8% 3 4 3 4 4 21%	1620
	11th to 20th	Day	16% 15% 8% 12% 8% 3 4 4 4 6% 21%	1589
	21st to end	Day	18% 15% 5% 10% 6% 3 4 4 4 6% 25%	1480
March	1st to 10th	Day	17% 13% 5% 9% 6% 3 4 4 4 6% 30%	1970
	11th to 20th	Day	18% 12% 6% 8% 5% 3 4 4 5% 5% 30%	1980
	21st to end	Day	22% 12% 4 9% 5% 3 4 4 4 5% 27%	2178
April	1st to 10th	Day	14% 12% 5% 7% 6% 3 4 5% 4 7% 32%	2042
	11th to 20th	Day	17% 11% 4 6% 5% 3 5% 4 5% 6% 33%	2222
	21st to end	Day	21% 10% 3 6% 6% 4 4 4 4 6% 32%	2340
May	1st to 10th	Day	18% 10% 4 7% 6% 3 6% 5% 5% 7% 28%	2340
	11th to 20th	Day	20% 7% 4 6% 7% 4 5% 5% 5% 7% 30%	2301
	21st to end	Day	10% 6% 3 6% 6% 4 6% 6% 8% 9% 36%	2607
June	1st to 10th	Day	14% 7% 3 7% 6% 3 6% 5% 6% 9% 35%	2520
	11th to 20th	Day	14% 7% 3 6% 7% 3 6% 5% 6% 9% 34%	2520
	21st to end	Day	13% 5% 3 5% 5% 3 5% 6% 7% 11% 37%	2520
July	1st to 10th	Day	10% 6% 3 7% 5% 3 5% 5% 6% 10% 39%	2375
	11th to 20th	Day	11% 5% 3 6% 6% 4 6% 6% 6% 10% 37%	2340
	21st to end	Day	11% 6% 3 7% 6% 4 6% 6% 7% 11% 34%	2547
August	1st to 10th	Day	10% 5% 3 6% 7% 5% 7% 5% 7% 10% 34%	2327
	11th to 20th	Day	12% 6% 2 6% 7% 5% 7% 6% 7% 9% 32%	2303
	21st to end	Day	11% 5% 3 6% 6% 5% 6% 5% 6% 8% 38%	2494
September	1st to 10th	Day	14% 6% 3 6% 5% 3 4 4 5% 7% 43%	2113
	11th to 20th	Day	10% 6% 2 5% 5% 3 5% 6% 6% 9% 42%	1980
	21st to end	Day	18% 7% 3 6% 7% 2 3 5% 5% 6% 37%	1980
October	1st to 10th	Day	15% 7% 3 6% 5% 3 4 5% 5% 8% 39%	1831
	11th to 20th	Day	19% 9% 3 7% 6% 4 4 5% 5% 6% 33%	1800
	21st to end	Day	23% 11% 4 6% 5% 3 4 4 4 5% 29%	1980
November	1st to 10th	Day	11% 9% 4 6% 5% 4 4 5% 5% 5% 41%	1726
	11th to 20th	Day	17% 14% 5% 6% 6% 3 4 4 3 6% 31%	1641
	21st to end	Day	18% 15% 7% 8% 5% 2 5% 4 6% 6% 24%	1520
December	1st to 10th	Day	21% 18% 8% 10% 6% 4 4 4 4 4 18%	1520
	11th to 20th	Day	18% 17% 7% 13% 6% 2 4 4 4 6% 19%	1910
	21st to end	Day	25% 24% 6% 10% 6% 3 3 3 4 4 12%	2850
January	1st to 10th	Night	17% 17% 7% 11% 7% 4 5% 5% 4 4 20%	2459
	11th to 20th	Night	20% 16% 6% 13% 7% 3 4 4 4 5% 18%	2391
	21st to end	Night	16% 18% 7% 12% 8% 3 4 4 3 4 21%	2574
February	1st to 10th	Night	21% 14% 6% 11% 7% 4 5% 4 4 5% 21%	2340
	11th to 20th	Night	18% 13% 6% 11% 7% 4 5% 4 4 5% 23%	2255
	21st to end	Night	20% 12% 6% 11% 7% 3 4 4 5% 4 24%	1776
March	1st to 10th	Night	17% 10% 5% 7% 7% 3 5% 4 4 5% 33%	1990
	11th to 20th	Night	19% 11% 4 6% 5% 3 4 4 5% 6% 34%	1980
	21st to end	Night	19% 11% 4 7% 6% 3 4 4 5% 4 33%	2178
April	1st to 10th	Night	17% 12% 4 5% 5% 3 4 5% 5% 7% 34%	1917
	11th to 20th	Night	15% 10% 4 6% 6% 3 4 5% 5% 8% 34%	1703
	21st to end	Night	16% 9% 3 7% 6% 3 4 4 5% 7% 35%	1620
May	1st to 10th	Night	17% 9% 3 6% 6% 4 6% 5% 5% 7% 31%	1620
	11th to 20th	Night	15% 8% 4 5% 5% 3 5% 5% 5% 9% 35%	1592
	21st to end	Night	8% 5% 2 4 6% 3 5% 6% 6% 10% 44%	1664
June	1st to 10th	Night	9% 6% 3 6% 5% 4 5% 5% 6% 8% 43%	1440
	11th to 20th	Night	12% 5% 3 5% 6% 3 4 4 6% 11% 42%	1440
	21st to end	Night	9% 5% 2 6% 5% 4 5% 7% 5% 8% 45%	1440
July	1st to 10th	Night	6% 5% 2 6% 6% 3 6% 6% 6% 9% 45%	1579
	11th to 20th	Night	8% 4 3 3 5% 4 4 5% 7% 11% 47%	1620
	21st to end	Night	8% 6% 3 6% 6% 4 6% 6% 7% 9% 39%	1771
August	1st to 10th	Night	7% 5% 2 5% 5% 2 5% 5% 7% 10% 46%	1611
	11th to 20th	Night	9% 6% 2 5% 5% 2 4 5% 6% 9% 46%	1598
	21st to end	Night	9% 4 3 5% 5% 3 4 6% 6% 8% 46%	1844
September	1st to 10th	Night	13% 5% 2 5% 4 2 4 5% 5% 6% 49%	1844
	11th to 20th	Night	10% 4 2 4 4 2 3 5% 5% 8% 52%	1980
	21st to end	Night	16% 7% 2 6% 4 3 4 4 5% 6% 43%	1980
October	1st to 10th	Night	13% 6% 2 5% 5% 3 3 4 5% 8% 44%	2128
	11th to 20th	Night	17% 8% 3 6% 5% 4 5% 5% 4 8% 34%	2160
	21st to end	Night	23% 10% 3 5% 5% 2 3 4 4 7% 34%	2376
November	1st to 10th	Night	14% 8% 3 5% 5% 3 4 4 5% 6% 43%	2347
	11th to 20th	Night	17% 12% 4 7% 5% 2 4 4 5% 6% 31%	2536
	21st to end	Night	19% 13% 5% 7% 6% 3 4 4 5% 6% 28%	2660
December	1st to 10th	Night	22% 17% 8% 9% 6% 3 4 4 4 5% 20%	2660
	11th to 20th	Night	18% 19% 7% 8% 6% 3 4 4 4 5% 22%	3285
	21st to end	Night	26% 20% 7% 9% 6% 2 4 4 4 5% 13%	4788

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	69% 5% 10% 11% 5%	1707
	11th to 20th	Day	73% 3 12% 10% 3	1647
	21st to end	Day	71% 5% 10% 11% 3 1	1782
February	1st to 10th	Day	68% 5% 9% 12% 6% 1	1620
	11th to 20th	Day	65% 5% 9% 14% 6%	1598
	21st to end	Day	61% 4 11% 15% 7% 1	1480
March	1st to 10th	Day	56% 4 12% 21% 7%	1970
	11th to 20th	Day	55% 7% 10% 17% 10% 2	1980
	21st to end	Day	59% 5% 9% 15% 10% 2	2178
April	1st to 10th	Day	50% 7% 12% 19% 12% 1	2042
	11th to 20th	Day	51% 7% 11% 15% 14% 3	2222
	21st to end	Day	53% 6% 10% 19% 10% 2	2340
May	1st to 10th	Day	54% 8% 11% 16% 9% 1	2340
	11th to 20th	Day	52% 8% 12% 15% 11% 2	2305
	21st to end	Day	40% 10% 15% 23% 10% 2	2607
June	1st to 10th	Day	45% 8% 14% 21% 12% 1	2520
	11th to 20th	Day	45% 8% 14% 21% 12% 1	2520
	21st to end	Day	40% 9% 13% 24% 13% 1	2520
July	1st to 10th	Day	41% 9% 14% 21% 13% 3	2310
	11th to 20th	Day	41% 8% 12% 24% 14% 1	2271
	21st to end	Day	41% 9% 15% 22% 13% 1	2405
August	1st to 10th	Day	42% 10% 15% 24% 9%	2314
	11th to 20th	Day	43% 9% 16% 22% 9% 1	2303
	21st to end	Day	41% 9% 13% 22% 12% 3	2494
September	1st to 10th	Day	40% 7% 12% 21% 17% 3	2113
	11th to 20th	Day	36% 7% 16% 25% 14% 1	1980
	21st to end	Day	47% 7% 11% 23% 13% 1	1980
October	1st to 10th	Day	43% 7% 13% 20% 16% 1	1831
	11th to 20th	Day	51% 6% 12% 20% 10% 1	1800
	21st to end	Day	55% 6% 12% 16% 10% 1	1980
November	1st to 10th	Day	42% 7% 12% 21% 16% 2	1726
	11th to 20th	Day	54% 5% 10% 19% 9% 3	1641
	21st to end	Day	59% 6% 12% 16% 6% 1	1520
December	1st to 10th	Day	70% 5% 10% 11% 3	1520
	11th to 20th	Day	67% 5% 9% 15% 4	1906
	21st to end	Day	76% 6% 9% 7% 2	2850
January	1st to 10th	Night	67% 6% 9% 13% 5%	2459
	11th to 20th	Night	69% 6% 10% 12% 3 1	2391
	21st to end	Night	68% 4 9% 14% 4 1	2574
February	1st to 10th	Night	66% 5% 10% 14% 5%	2340
	11th to 20th	Night	64% 4 10% 14% 7%	2257
	21st to end	Night	64% 5% 9% 12% 9% 2	1776
March	1st to 10th	Night	54% 4 10% 20% 11% 1	1990
	11th to 20th	Night	50% 5% 13% 20% 9% 2	1980
	21st to end	Night	53% 5% 8% 18% 13% 2	2178
April	1st to 10th	Night	49% 6% 10% 19% 13% 2	1917
	11th to 20th	Night	46% 8% 11% 16% 15% 3	1703
	21st to end	Night	46% 6% 12% 18% 15% 2	1620
May	1st to 10th	Night	50% 8% 10% 17% 13% 3	1620
	11th to 20th	Night	45% 9% 11% 17% 15% 3	1593
	21st to end	Night	34% 9% 17% 26% 13% 1	1665
June	1st to 10th	Night	37% 9% 14% 23% 16% 2	1440
	11th to 20th	Night	36% 7% 16% 23% 16% 2	1440
	21st to end	Night	35% 10% 13% 24% 17% 1	1440
July	1st to 10th	Night	35% 9% 13% 22% 17% 3	1534
	11th to 20th	Night	29% 9% 16% 27% 17% 2	1566
	21st to end	Night	38% 10% 15% 21% 13% 3	1672
August	1st to 10th	Night	32% 9% 15% 28% 15% 1	1600
	11th to 20th	Night	34% 8% 17% 24% 14% 2	1598
	21st to end	Night	33% 8% 14% 25% 16% 3	1844
September	1st to 10th	Night	34% 8% 11% 23% 18% 5%	1844
	11th to 20th	Night	29% 7% 15% 26% 21% 2	1980
	21st to end	Night	40% 6% 13% 22% 18% 1	1980
October	1st to 10th	Night	38% 7% 14% 22% 16% 2	2128
	11th to 20th	Night	47% 6% 12% 22% 12% 1	2160
	21st to end	Night	52% 5% 10% 20% 11% 2	2376
November	1st to 10th	Night	40% 6% 12% 22% 16% 3	2347
	11th to 20th	Night	52% 5% 11% 19% 9% 3	2536
	21st to end	Night	58% 5% 12% 19% 6% 1	2660
December	1st to 10th	Night	68% 5% 10% 12% 5%	2660
	11th to 20th	Night	65% 5% 12% 15% 3	3288
	21st to end	Night	73% 6% 10% 9% 2	4788

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	33% 24% 27% 11% 4	270
	11th to 20th	Day	34% 29% 30% 6% 1	249
	21st to end	Day	28% 35% 28% 7% 2	264
February	1st to 10th	Day	38% 21% 35% 6%	240
	11th to 20th	Day	38% 28% 29% 5%	240
	21st to end	Day	40% 25% 29% 6%	198
March	1st to 10th	Day	28% 25% 30% 14% 3	410
	11th to 20th	Day	30% 21% 31% 12% 6% 1	420
	21st to end	Day	32% 21% 28% 15% 3 1	462
April	1st to 10th	Day	26% 24% 28% 13% 7% 2	420
	11th to 20th	Day	27% 18% 27% 17% 9% 2	412
	21st to end	Day	30% 16% 32% 15% 6% 2	420
May	1st to 10th	Day	27% 20% 28% 16% 7% 3	423
	11th to 20th	Day	22% 13% 32% 21% 8% 4	447
	21st to end	Day	16% 8% 26% 28% 15% 6%	485
June	1st to 10th	Day	14% 11% 31% 27% 13% 4	450
	11th to 20th	Day	18% 11% 26% 26% 15% 4	450
	21st to end	Day	14% 10% 32% 26% 14% 3	450
July	1st to 10th	Day	13% 6% 22% 27% 21% 11%	445
	11th to 20th	Day	10% 7% 28% 28% 18% 8%	444
	21st to end	Day	11% 7% 25% 32% 16% 9%	488
August	1st to 10th	Day	13% 6% 22% 29% 22% 9%	446
	11th to 20th	Day	15% 5% 22% 28% 20% 10%	439
	21st to end	Day	12% 5% 26% 27% 19% 10%	495
September	1st to 10th	Day	15% 9% 21% 27% 19% 9%	450
	11th to 20th	Day	12% 6% 20% 30% 22% 11%	450
	21st to end	Day	21% 11% 25% 22% 16% 5%	450
October	1st to 10th	Day	15% 10% 28% 26% 17% 4	450
	11th to 20th	Day	23% 15% 33% 20% 8% 1	450
	21st to end	Day	32% 15% 31% 16% 5%	495
November	1st to 10th	Day	20% 21% 32% 14% 10% 2	324
	11th to 20th	Day	27% 21% 30% 14% 6% 2	237
	21st to end	Day	24% 24% 42% 9% 1	180
December	1st to 10th	Day	32% 28% 28% 7% 4 2	180
	11th to 20th	Day	29% 23% 33% 11% 3	180
	21st to end	Day	37% 24% 26% 10% 2	222
January	1st to 10th	Night	28% 22% 34% 13% 3	760
	11th to 20th	Night	31% 19% 31% 15% 3	736
	21st to end	Night	28% 23% 29% 18% 3	792
February	1st to 10th	Night	31% 18% 30% 18% 2	720
	11th to 20th	Night	28% 21% 36% 13% 2	703
	21st to end	Night	30% 21% 31% 15% 2	592
March	1st to 10th	Night	24% 20% 33% 20% 3	720
	11th to 20th	Night	27% 18% 27% 23% 5% 1	720
	21st to end	Night	26% 14% 33% 22% 5% 1	792
April	1st to 10th	Night	25% 16% 30% 23% 6%	720
	11th to 20th	Night	23% 14% 33% 21% 9% 1	639
	21st to end	Night	22% 11% 35% 25% 7%	540
May	1st to 10th	Night	24% 9% 26% 31% 9% 1	540
	11th to 20th	Night	19% 9% 27% 30% 13% 1	531
	21st to end	Night	12% 4 24% 35% 23% 3	504
June	1st to 10th	Night	12% 4 26% 42% 16%	360
	11th to 20th	Night	13% 6% 25% 39% 17% 1	360
	21st to end	Night	10% 3 27% 36% 23% 1	360
July	1st to 10th	Night	8% 2 18% 38% 26% 8%	484
	11th to 20th	Night	9% 2 20% 37% 27% 5%	522
	21st to end	Night	12% 3 17% 37% 29% 2	591
August	1st to 10th	Night	10% 2 15% 39% 31% 2	537
	11th to 20th	Night	12% 3 13% 40% 28% 4	534
	21st to end	Night	11% 4 21% 30% 27% 7%	656
September	1st to 10th	Night	15% 4 20% 30% 27% 4	720
	11th to 20th	Night	10% 5% 16% 35% 30% 4	720
	21st to end	Night	19% 8% 24% 26% 20% 4	720
October	1st to 10th	Night	17% 9% 23% 28% 21% 3	720
	11th to 20th	Night	22% 12% 31% 23% 11% 1	720
	21st to end	Night	28% 14% 28% 23% 7%	792
November	1st to 10th	Night	18% 15% 26% 30% 11%	740
	11th to 20th	Night	26% 18% 27% 21% 7% 1	760
	21st to end	Night	29% 16% 28% 21% 5%	760
December	1st to 10th	Night	32% 19% 27% 18% 4	760
	11th to 20th	Night	30% 18% 29% 19% 4	760
	21st to end	Night	31% 18% 32% 17% 2	836

Page generated at 2024-01-11 13:31:59. Version ac07

Copyright 2024 Attilla Danko