Bull Domingo Astro
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Bull Domingo Astro clear sky chart from 2005-11-06 to 2024-04-10.

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	3 4 2 5% 4 3 5% 5% 6% 8% 55%	83299
	Night	2 4 2 4 4 2 4 4 5% 8% 61%	85585
Transparency	Day	25% 7% 12% 24% 23% 9%	83012
	Night	21% 6% 13% 27% 25% 9%	85394
Seeing	Day	9% 13% 29% 26% 16% 5%	14577
	Night	6% 10% 33% 33% 16% 3	24801

By Month

Percentage Cloud Cover SW (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	1 3 2 4 4 2 4 5% 6% 9% 60%	2538
	11th to 20th	Day	2 1 4 4 2 3 4 6% 9% 64%	2775
	21st to end	Day	6% 4 6% 4 2 3 4 5% 8% 57%	3146
February	1st to 10th	Day	5% 3 6% 4 2 3 3 6% 8% 60%	1710
	11th to 20th	Day	1 3 2 5% 4 2 3 4 5% 8% 64%	1844
	21st to end	Day	1 5% 3 6% 5% 2 4 3 5% 8% 59%	1570
March	1st to 10th	Day	4 3 5% 3 2 3 4 4 8% 63%	3153
	11th to 20th	Day	2 11% 6% 7% 5% 3 5% 5% 6% 6% 44%	3490
	21st to end	Day	1 5% 3 5% 4 3 4 5% 5% 8% 57%	4027
April	1st to 10th	Day	2 5% 2 4 4 2 5% 5% 6% 8% 57%	2269
	11th to 20th	Day	4 7% 2 6% 6% 4 4 4 6% 7% 50%	2131
	21st to end	Day	4 7% 3 5% 6% 3 5% 6% 7% 8% 47%	2160
May	1st to 10th	Day	4 7% 3 6% 4 3 6% 6% 7% 8% 46%	2194
	11th to 20th	Day	6% 6% 3 6% 5% 4 6% 6% 7% 9% 42%	2428
	21st to end	Day	4 3 2 3 5% 4 5% 6% 6% 10% 51%	2724
June	1st to 10th	Day	3 3 2 5% 4 3 5% 7% 8% 12% 49%	2520
	11th to 20th	Day	3 3 1 3 4 3 5% 6% 7% 9% 57%	2520
	21st to end	Day	3 3 2 3 6% 3 6% 8% 8% 10% 49%	2520
July	1st to 10th	Day	5% 4 2 5% 5% 4 6% 6% 7% 10% 47%	2520
	11th to 20th	Day	3 4 2 4 7% 4 7% 7% 7% 10% 44%	2520
	21st to end	Day	5% 4 2 7% 7% 5% 8% 8% 10% 10% 32%	2583
August	1st to 10th	Day	5% 5% 2 6% 7% 4 8% 7% 7% 9% 39%	2307
	11th to 20th	Day	4 4 3 4 5% 4 6% 7% 8% 9% 47%	2123
	21st to end	Day	5% 4 2 4 5% 4 5% 7% 7% 9% 49%	2376
September	1st to 10th	Day	4 4 2 4 5% 3 5% 5% 7% 8% 53%	2160
	11th to 20th	Day	4 2 1 3 4 2 4 5% 5% 8% 62%	2152
	21st to end	Day	4 2 1 4 4 2 3 4 3 5% 67%	1980
October	1st to 10th	Day	4 3 2 4 4 3 5% 5% 6% 6% 58%	1800
	11th to 20th	Day	2 3 1 2 2 1 3 3 3 7% 73%	1800
	21st to end	Day	3 5% 2 3 3 2 3 3 4 6% 67%	1973
November	1st to 10th	Day	1 3 1 3 2 1 2 3 4 8% 71%	1673
	11th to 20th	Day	3 1 3 3 2 3 3 4 8% 70%	1710
	21st to end	Day	1 4 2 4 4 1 3 3 5% 7% 66%	1663
December	1st to 10th	Day	3 2 3 3 2 3 3 5% 8% 68%	1520
	11th to 20th	Day	1 2 2 4 2 2 2 3 6% 10% 64%	1926
	21st to end	Day	1 3 2 6% 4 3 4 4 5% 6% 61%	2794
January	1st to 10th	Night	3 3 7% 5% 3 4 4 5% 8% 60%	4417
	11th to 20th	Night	1 2 1 2 3 2 4 5% 5% 7% 68%	4224
	21st to end	Night	4 3 5% 4 2 3 5% 5% 8% 61%	4521
February	1st to 10th	Night	1 4 3 5% 5% 2 2 3 4 7% 65%	2470
	11th to 20th	Night	1 4 2 4 4 2 4 4 5% 7% 63%	2221
	21st to end	Night	3 2 5% 4 2 3 4 4 6% 66%	1884
March	1st to 10th	Night	1 5% 3 4 2 2 3 3 5% 7% 66%	3708
	11th to 20th	Night	1 9% 4 5% 3 2 3 4 5% 7% 56%	3490
	21st to end	Night	1 5% 2 4 4 2 3 3 5% 7% 62%	3617
April	1st to 10th	Night	1 5% 2 4 3 1 3 3 5% 8% 64%	1900
	11th to 20th	Night	4 7% 3 5% 4 2 3 4 4 8% 57%	1777
	21st to end	Night	4 6% 3 5% 4 3 4 5% 4 8% 56%	1800
May	1st to 10th	Night	4 6% 3 5% 4 2 4 4 4 7% 56%	1764
	11th to 20th	Night	6% 8% 2 5% 3 3 5% 6% 7% 8% 47%	1464
	21st to end	Night	6% 4 1 4 4 2 4 4 5% 9% 57%	1552
June	1st to 10th	Night	3 3 2 3 2 2 4 5% 7% 8% 60%	1440
	11th to 20th	Night	2 2 2 2 2 2 3 3 5% 8% 68%	1440
	21st to end	Night	3 2 2 4 5% 3 5% 5% 8% 10% 53%	1440
July	1st to 10th	Night	5% 4 2 5% 5% 4 8% 8% 9% 9% 41%	1440
	11th to 20th	Night	4 3 2 4 4 3 5% 6% 8% 10% 51%	1440
	21st to end	Night	4 5% 3 5% 6% 4 7% 7% 10% 12% 38%	1730
August	1st to 10th	Night	5% 4 2 5% 5% 3 5% 6% 8% 11% 44%	1632
	11th to 20th	Night	4 4 2 5% 4 4 5% 6% 8% 10% 48%	1778
	21st to end	Night	4 3 2 5% 4 3 5% 6% 8% 10% 50%	1980
September	1st to 10th	Night	4 4 2 4 5% 3 5% 5% 6% 9% 52%	1800
	11th to 20th	Night	4 4 1 3 3 2 3 4 5% 7% 62%	1806
	21st to end	Night	4 2 1 3 4 2 3 4 4 7% 66%	1980
October	1st to 10th	Night	4 3 2 3 3 2 3 3 5% 7% 65%	2157
	11th to 20th	Night	1 1 1 2 2 1 3 3 4 5% 78%	2160
	21st to end	Night	3 5% 1 3 3 2 2 3 4 6% 68%	2376
November	1st to 10th	Night	1 2 2 2 2 1 2 3 4 7% 73%	2391
	11th to 20th	Night	1 2 1 2 3 1 3 4 4 6% 74%	2470
	21st to end	Night	1 5% 2 3 3 1 3 2 5% 7% 67%	2512
December	1st to 10th	Night	2 2 3 3 2 3 3 5% 8% 68%	2660
	11th to 20th	Night	1 3 2 4 3 1 3 4 6% 9% 62%	3271
	21st to end	Night	3 2 5% 5% 3 4 4 6% 8% 60%	4873

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	17% 5% 16% 30% 26% 5%	2539
	11th to 20th	Day	15% 5% 15% 36% 24% 5%	2775
	21st to end	Day	25% 5% 10% 32% 22% 6%	3146
February	1st to 10th	Day	23% 4 13% 28% 22% 9%	1710
	11th to 20th	Day	18% 5% 11% 27% 29% 10%	1854
	21st to end	Day	22% 5% 10% 22% 26% 14%	1570
March	1st to 10th	Day	18% 5% 9% 19% 37% 12%	3153
	11th to 20th	Day	35% 6% 13% 28% 15% 4	3490
	21st to end	Day	22% 7% 11% 36% 22% 3	4027
April	1st to 10th	Day	24% 5% 13% 22% 23% 12%	2269
	11th to 20th	Day	33% 5% 10% 25% 20% 8%	2134
	21st to end	Day	31% 7% 13% 23% 20% 6%	2160
May	1st to 10th	Day	34% 7% 13% 21% 20% 6%	2194
	11th to 20th	Day	36% 10% 15% 21% 15% 4	2432
	21st to end	Day	26% 8% 13% 20% 21% 11%	2724
June	1st to 10th	Day	24% 10% 14% 22% 20% 10%	2520
	11th to 20th	Day	21% 8% 10% 16% 24% 21%	2520
	21st to end	Day	26% 9% 14% 19% 20% 12%	2520
July	1st to 10th	Day	30% 10% 13% 16% 20% 11%	2451
	11th to 20th	Day	31% 9% 15% 26% 13% 5%	2445
	21st to end	Day	38% 14% 21% 19% 8% 1	2439
August	1st to 10th	Day	38% 12% 16% 14% 14% 6%	2292
	11th to 20th	Day	31% 9% 12% 21% 19% 8%	2123
	21st to end	Day	29% 9% 14% 22% 22% 5%	2376
September	1st to 10th	Day	27% 8% 12% 21% 22% 12%	2160
	11th to 20th	Day	20% 6% 12% 18% 28% 15%	2152
	21st to end	Day	20% 4 8% 24% 33% 11%	1980
October	1st to 10th	Day	24% 7% 10% 20% 27% 11%	1800
	11th to 20th	Day	14% 2 10% 19% 39% 15%	1800
	21st to end	Day	20% 3 8% 27% 32% 11%	1973
November	1st to 10th	Day	13% 3 11% 21% 38% 14%	1673
	11th to 20th	Day	14% 4 10% 32% 32% 9%	1710
	21st to end	Day	20% 2 9% 22% 32% 15%	1663
December	1st to 10th	Day	16% 5% 16% 29% 25% 8%	1520
	11th to 20th	Day	16% 5% 15% 27% 28% 9%	1924
	21st to end	Day	19% 8% 11% 25% 23% 13%	2794
January	1st to 10th	Night	21% 5% 12% 27% 27% 6%	4417
	11th to 20th	Night	13% 5% 12% 40% 25% 6%	4224
	21st to end	Night	20% 7% 13% 32% 22% 5%	4521
February	1st to 10th	Night	22% 3 12% 31% 22% 10%	2470
	11th to 20th	Night	21% 5% 11% 28% 27% 8%	2221
	21st to end	Night	18% 4 9% 25% 32% 12%	1884
March	1st to 10th	Night	18% 3 9% 23% 37% 10%	3708
	11th to 20th	Night	26% 6% 12% 32% 19% 4	3490
	21st to end	Night	21% 6% 13% 37% 21% 2	3617
April	1st to 10th	Night	18% 5% 14% 27% 27% 8%	1900
	11th to 20th	Night	26% 6% 10% 27% 25% 6%	1777
	21st to end	Night	27% 6% 13% 29% 19% 6%	1800
May	1st to 10th	Night	28% 6% 12% 28% 20% 6%	1764
	11th to 20th	Night	34% 9% 18% 19% 15% 5%	1465
	21st to end	Night	25% 7% 15% 23% 20% 11%	1552
June	1st to 10th	Night	22% 8% 18% 21% 18% 13%	1440
	11th to 20th	Night	15% 7% 12% 22% 24% 20%	1440
	21st to end	Night	25% 8% 13% 19% 21% 13%	1440
July	1st to 10th	Night	33% 13% 14% 15% 16% 9%	1400
	11th to 20th	Night	23% 10% 21% 26% 13% 6%	1392
	21st to end	Night	34% 18% 23% 18% 7% 1	1634
August	1st to 10th	Night	31% 13% 20% 18% 12% 7%	1623
	11th to 20th	Night	29% 9% 18% 24% 14% 6%	1778
	21st to end	Night	27% 10% 17% 23% 18% 5%	1980
September	1st to 10th	Night	27% 7% 14% 24% 21% 8%	1800
	11th to 20th	Night	20% 7% 12% 21% 25% 15%	1806
	21st to end	Night	19% 5% 11% 23% 33% 9%	1980
October	1st to 10th	Night	19% 7% 11% 24% 27% 12%	2157
	11th to 20th	Night	10% 3 10% 21% 39% 16%	2160
	21st to end	Night	18% 4 8% 29% 29% 12%	2376
November	1st to 10th	Night	12% 3 11% 26% 33% 14%	2391
	11th to 20th	Night	13% 4 9% 33% 30% 12%	2470
	21st to end	Night	17% 4 10% 22% 33% 14%	2512
December	1st to 10th	Night	16% 5% 16% 29% 25% 9%	2660
	11th to 20th	Night	17% 5% 15% 25% 30% 8%	3272
	21st to end	Night	19% 9% 12% 25% 23% 12%	4873

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	14% 17% 34% 20% 10% 4	270
	11th to 20th	Day	15% 17% 37% 24% 5% 1	270
	21st to end	Day	4 15% 41% 27% 10% 3	297
February	1st to 10th	Day	11% 23% 46% 16% 3 1	270
	11th to 20th	Day	10% 30% 39% 16% 3 1	270
	21st to end	Day	18% 21% 40% 16% 5%	225
March	1st to 10th	Day	14% 20% 38% 20% 7% 1	280
	11th to 20th	Day	13% 21% 35% 22% 8% 2	460
	21st to end	Day	16% 27% 36% 17% 4	506
April	1st to 10th	Day	16% 23% 33% 20% 6% 1	457
	11th to 20th	Day	18% 27% 34% 15% 5% 1	412
	21st to end	Day	16% 24% 37% 15% 7% 1	420
May	1st to 10th	Day	12% 19% 37% 21% 9% 2	457
	11th to 20th	Day	12% 10% 27% 31% 16% 3	625
	21st to end	Day	8% 13% 30% 28% 16% 5%	679
June	1st to 10th	Day	6% 9% 27% 29% 22% 7%	630
	11th to 20th	Day	5% 10% 32% 31% 17% 6%	630
	21st to end	Day	5% 7% 28% 29% 24% 7%	630
July	1st to 10th	Day	8% 2 16% 36% 28% 10%	621
	11th to 20th	Day	4 2 13% 35% 35% 11%	618
	21st to end	Day	8% 2 10% 32% 34% 14%	525
August	1st to 10th	Day	7% 3 16% 36% 26% 12%	447
	11th to 20th	Day	5% 2 22% 36% 25% 9%	437
	21st to end	Day	9% 3 19% 36% 25% 8%	495
September	1st to 10th	Day	7% 5% 22% 32% 24% 10%	450
	11th to 20th	Day	6% 8% 30% 33% 19% 4	442
	21st to end	Day	7% 7% 23% 28% 28% 8%	270
October	1st to 10th	Day	10% 11% 27% 21% 23% 9%	270
	11th to 20th	Day	8% 15% 30% 27% 14% 6%	270
	21st to end	Day	12% 13% 31% 25% 15% 3	297
November	1st to 10th	Day	8% 20% 32% 25% 13% 3	270
	11th to 20th	Day	5% 19% 41% 22% 9% 4	270
	21st to end	Day	7% 15% 38% 30% 8% 2	270
December	1st to 10th	Day	12% 21% 36% 22% 8% 1	270
	11th to 20th	Day	9% 22% 39% 18% 10% 2	270
	21st to end	Day	12% 24% 42% 18% 4 1	297
January	1st to 10th	Night	5% 18% 36% 29% 10% 2	950
	11th to 20th	Night	5% 19% 39% 27% 8% 2	822
	21st to end	Night	3 12% 45% 32% 8% 1	836
February	1st to 10th	Night	4 13% 52% 25% 5%	760
	11th to 20th	Night	5% 14% 51% 23% 7%	744
	21st to end	Night	4 14% 54% 26% 2	628
March	1st to 10th	Night	6% 17% 42% 28% 6% 1	760
	11th to 20th	Night	6% 8% 39% 35% 11% 1	760
	21st to end	Night	7% 13% 44% 31% 5%	715
April	1st to 10th	Night	8% 12% 45% 29% 6%	570
	11th to 20th	Night	10% 14% 37% 31% 7% 1	533
	21st to end	Night	9% 12% 35% 33% 11% 1	540
May	1st to 10th	Night	7% 10% 31% 40% 10% 1	540
	11th to 20th	Night	12% 6% 25% 36% 18% 2	531
	21st to end	Night	10% 10% 27% 34% 16% 3	584
June	1st to 10th	Night	6% 7% 21% 40% 25% 2	540
	11th to 20th	Night	3 7% 26% 45% 17% 2	540
	21st to end	Night	3 4 18% 39% 32% 3	540
July	1st to 10th	Night	8% 2 8% 37% 40% 6%	525
	11th to 20th	Night	6% 1 5% 37% 42% 10%	522
	21st to end	Night	5% 2 3 30% 53% 7%	591
August	1st to 10th	Night	7% 2 6% 35% 40% 10%	537
	11th to 20th	Night	7% 1 10% 41% 35% 6%	534
	21st to end	Night	5% 2 11% 40% 36% 6%	594
September	1st to 10th	Night	5% 3 14% 41% 29% 8%	540
	11th to 20th	Night	7% 4 21% 39% 24% 5%	540
	21st to end	Night	5% 6% 26% 37% 22% 4	540
October	1st to 10th	Night	7% 7% 28% 39% 17% 3	717
	11th to 20th	Night	3 7% 34% 38% 16% 3	720
	21st to end	Night	6% 7% 36% 33% 16% 3	792
November	1st to 10th	Night	3 11% 36% 35% 14% 2	911
	11th to 20th	Night	4 12% 40% 30% 11% 2	950
	21st to end	Night	6% 10% 37% 35% 11% 1	950
December	1st to 10th	Night	4 15% 41% 32% 7% 1	950
	11th to 20th	Night	5% 15% 45% 26% 8% 1	950
	21st to end	Night	6% 19% 44% 24% 5% 1	1045

Page generated at 2024-04-07 07:28:11. Version ac07

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