Observatorio De Solitario
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Observatorio De Solitario clear sky chart from 2005-11-06 to 2026-09-14.

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	3 2 1 3 3 3 3 3 5% 8% 66%	155889
	Night	3 3 1 3 3 3 4 3 5% 8% 64%	152734
Transparency	Day	17% 5% 9% 20% 26% 24%	151003
	Night	18% 5% 9% 20% 24% 24%	148627
Seeing	Day	5% 6% 20% 34% 28% 8%	16854
	Night	5% 4 20% 46% 24% 1	26975

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	2 2 1 2 2 2 2 2 4 6% 75%	5885
	11th to 20th	Day	3 3 1 3 2 2 2 2 4 5% 73%	5910
	21st to end	Day	4 4 2 4 3 3 4 3 4 6% 63%	6468
February	1st to 10th	Day	3 4 2 4 4 3 3 3 5% 4 65%	2100
	11th to 20th	Day	4 4 2 4 3 3 3 2 4 6% 64%	2049
	21st to end	Day	3 3 1 2 3 3 3 3 5% 7% 69%	1730
March	1st to 10th	Day	3 3 1 3 3 3 4 3 5% 6% 66%	4600
	11th to 20th	Day	6% 2 1 2 2 2 2 3 4 6% 70%	4893
	21st to end	Day	2 3 1 3 3 3 3 3 5% 6% 67%	6090
April	1st to 10th	Day	2 2 1 3 3 3 3 3 5% 7% 68%	2520
	11th to 20th	Day	3 3 1 3 2 3 3 3 5% 6% 69%	2491
	21st to end	Day	3 3 1 3 3 2 2 3 5% 5% 71%	2520
May	1st to 10th	Day	2 2 1 2 2 2 2 2 4 6% 75%	7057
	11th to 20th	Day	2 2 1 3 3 3 4 3 5% 7% 65%	7032
	21st to end	Day	2 2 1 3 2 3 3 3 6% 8% 67%	8066
June	1st to 10th	Day	2 1 1 2 2 2 4 4 6% 8% 70%	2730
	11th to 20th	Day	2 2 1 3 3 3 4 3 5% 8% 65%	2730
	21st to end	Day	3 2 1 3 3 4 4 3 7% 10% 59%	2636
July	1st to 10th	Day	3 2 1 4 3 3 4 4 7% 11% 59%	7079
	11th to 20th	Day	5% 4 2 5% 4 5% 6% 5% 7% 11% 46%	7080
	21st to end	Day	2 1 1 3 3 3 4 4 5% 9% 66%	7686
August	1st to 10th	Day	1 1 1 1 2 3 3 6% 11% 70%	6988
	11th to 20th	Day	2 2 1 3 3 4 5% 4 9% 13% 55%	7003
	21st to end	Day	1 1 1 2 2 2 3 3 5% 9% 69%	7751
September	1st to 10th	Day	5% 5% 2 6% 4 5% 5% 5% 7% 10% 47%	2520
	11th to 20th	Day	8% 4 1 4 4 4 5% 4 6% 8% 52%	2296
	21st to end	Day	5% 3 1 4 3 3 3 4 6% 7% 62%	2200
October	1st to 10th	Day	2 2 1 1 2 2 2 2 4 5% 80%	3590
	11th to 20th	Day	4 1 1 2 2 2 2 3 4 5% 74%	3442
	21st to end	Day	3 1 1 1 1 1 1 1 2 3 84%	3548
November	1st to 10th	Day	5% 2 1 2 1 1 2 2 3 5% 75%	2021
	11th to 20th	Day	4 3 1 2 2 2 3 3 4 6% 69%	1890
	21st to end	Day	5% 3 1 3 3 3 3 3 4 7% 65%	1890
December	1st to 10th	Day	7% 6% 2 6% 3 3 3 2 4 8% 57%	3030
	11th to 20th	Day	2 3 1 4 3 3 3 3 4 6% 68%	3481
	21st to end	Day	2 2 1 2 2 2 2 2 4 5% 75%	4887
January	1st to 10th	Night	2 2 1 2 2 2 2 2 3 6% 76%	7038
	11th to 20th	Night	4 2 1 2 2 2 2 2 4 5% 73%	7080
	21st to end	Night	6% 4 2 4 3 3 4 3 6% 7% 58%	7746
February	1st to 10th	Night	4 3 1 4 3 3 3 3 4 6% 65%	2520
	11th to 20th	Night	5% 4 1 4 3 3 4 3 4 7% 62%	2458
	21st to end	Night	4 3 1 3 2 3 4 3 4 5% 67%	2076
March	1st to 10th	Night	3 4 2 4 3 3 3 3 5% 6% 64%	5494
	11th to 20th	Night	7% 3 1 2 2 2 2 3 4 5% 70%	5301
	21st to end	Night	3 3 1 4 3 3 3 3 5% 6% 67%	5102
April	1st to 10th	Night	4 4 1 3 3 3 3 4 5% 6% 64%	2100
	11th to 20th	Night	3 2 1 2 3 3 3 3 5% 7% 66%	2077
	21st to end	Night	3 3 1 2 3 4 3 3 4 5% 69%	2100
May	1st to 10th	Night	3 2 1 3 2 2 3 3 4 6% 71%	5890
	11th to 20th	Night	6% 3 2 4 3 3 4 4 5% 8% 59%	5860
	21st to end	Night	3 2 1 4 3 4 5% 4 5% 7% 62%	6105
June	1st to 10th	Night	2 2 1 4 3 4 5% 4 9% 9% 57%	1890
	11th to 20th	Night	2 2 1 4 4 5% 5% 4 8% 10% 54%	1890
	21st to end	Night	3 4 1 5% 3 4 4 4 8% 10% 54%	1973
July	1st to 10th	Night	3 3 2 4 3 5% 5% 5% 9% 13% 49%	5910
	11th to 20th	Night	3 3 2 5% 4 5% 6% 5% 8% 12% 48%	5910
	21st to end	Night	1 2 1 4 4 4 5% 4 7% 10% 59%	6423
August	1st to 10th	Night	1 1 2 2 2 3 3 6% 12% 68%	5834
	11th to 20th	Night	1 1 1 3 3 4 6% 6% 10% 15% 51%	5853
	21st to end	Night	1 1 1 2 2 3 4 4 6% 10% 66%	6465
September	1st to 10th	Night	5% 4 2 4 5% 5% 5% 5% 7% 10% 49%	2100
	11th to 20th	Night	6% 3 2 7% 4 5% 6% 5% 7% 10% 46%	2169
	21st to end	Night	5% 5% 1 4 5% 4 5% 5% 6% 9% 52%	2200
October	1st to 10th	Night	2 1 1 2 2 2 3 3 3 5% 77%	3590
	11th to 20th	Night	4 2 1 3 2 2 3 3 4 6% 70%	3695
	21st to end	Night	3 2 1 2 1 1 1 1 2 4 82%	4252
November	1st to 10th	Night	5% 2 1 2 1 1 2 2 3 4 77%	2473
	11th to 20th	Night	4 2 1 2 2 2 2 3 4 6% 71%	2730
	21st to end	Night	5% 3 1 3 3 3 3 3 5% 6% 67%	2730
December	1st to 10th	Night	6% 3 3 6% 4 5% 5% 5% 5% 6% 51%	4380
	11th to 20th	Night	2 3 1 3 2 2 3 3 4 6% 72%	4946
	21st to end	Night	2 2 1 3 2 2 3 2 5% 6% 72%	6374

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	12% 3 5% 25% 30% 25%	5888
	11th to 20th	Day	15% 2 5% 16% 37% 25%	5910
	21st to end	Day	23% 4 5% 19% 30% 19%	6468
February	1st to 10th	Day	22% 3 5% 14% 25% 32%	2100
	11th to 20th	Day	22% 5% 7% 14% 24% 29%	2059
	21st to end	Day	15% 4 4 12% 28% 36%	1730
March	1st to 10th	Day	18% 4 4 10% 21% 43%	4600
	11th to 20th	Day	15% 4 5% 10% 18% 47%	4893
	21st to end	Day	16% 4 5% 9% 25% 42%	6090
April	1st to 10th	Day	16% 5% 7% 12% 23% 37%	2520
	11th to 20th	Day	16% 5% 6% 13% 22% 38%	2494
	21st to end	Day	16% 4 5% 13% 24% 39%	2520
May	1st to 10th	Day	12% 4 6% 14% 21% 43%	7057
	11th to 20th	Day	16% 5% 6% 11% 25% 37%	7035
	21st to end	Day	13% 5% 8% 21% 22% 29%	8067
June	1st to 10th	Day	10% 6% 11% 25% 29% 19%	2730
	11th to 20th	Day	17% 5% 8% 16% 31% 23%	2730
	21st to end	Day	18% 7% 14% 23% 23% 14%	2636
July	1st to 10th	Day	18% 8% 17% 31% 22% 5%	7021
	11th to 20th	Day	29% 7% 17% 31% 13% 4	7017
	21st to end	Day	15% 5% 14% 29% 28% 8%	7516
August	1st to 10th	Day	11% 4 12% 34% 31% 8%	5532
	11th to 20th	Day	17% 7% 17% 40% 17% 3	5519
	21st to end	Day	13% 6% 13% 27% 32% 9%	6078
September	1st to 10th	Day	30% 9% 15% 20% 15% 10%	2520
	11th to 20th	Day	28% 8% 13% 19% 23% 9%	2296
	21st to end	Day	21% 7% 11% 21% 25% 15%	2200
October	1st to 10th	Day	8% 5% 8% 15% 24% 40%	3590
	11th to 20th	Day	14% 4 9% 20% 18% 34%	3442
	21st to end	Day	9% 2 3 12% 41% 33%	3548
November	1st to 10th	Day	13% 3 8% 18% 29% 29%	2021
	11th to 20th	Day	16% 4 8% 20% 29% 23%	1890
	21st to end	Day	20% 4 8% 22% 24% 22%	1890
December	1st to 10th	Day	28% 4 7% 19% 25% 17%	3030
	11th to 20th	Day	17% 4 5% 24% 30% 20%	3479
	21st to end	Day	12% 3 4 15% 38% 29%	4887
January	1st to 10th	Night	13% 2 3 21% 35% 26%	7038
	11th to 20th	Night	15% 2 5% 13% 31% 35%	7080
	21st to end	Night	25% 5% 5% 18% 27% 20%	7746
February	1st to 10th	Night	21% 3 5% 13% 25% 33%	2520
	11th to 20th	Night	22% 4 8% 14% 23% 29%	2458
	21st to end	Night	18% 5% 5% 10% 27% 35%	2076
March	1st to 10th	Night	19% 4 4 10% 21% 42%	5494
	11th to 20th	Night	16% 7% 6% 8% 17% 44%	5301
	21st to end	Night	16% 4 6% 10% 21% 42%	5102
April	1st to 10th	Night	20% 5% 7% 14% 19% 35%	2100
	11th to 20th	Night	16% 6% 9% 16% 17% 36%	2077
	21st to end	Night	15% 5% 8% 17% 22% 33%	2100
May	1st to 10th	Night	14% 5% 9% 18% 19% 36%	5888
	11th to 20th	Night	20% 6% 7% 15% 20% 31%	5861
	21st to end	Night	20% 6% 10% 24% 17% 24%	6107
June	1st to 10th	Night	17% 7% 14% 28% 21% 12%	1890
	11th to 20th	Night	21% 8% 10% 17% 27% 16%	1890
	21st to end	Night	22% 7% 15% 21% 22% 13%	1973
July	1st to 10th	Night	22% 7% 21% 31% 17% 2	5860
	11th to 20th	Night	25% 8% 19% 30% 14% 3	5850
	21st to end	Night	17% 7% 16% 29% 28% 4	6280
August	1st to 10th	Night	10% 5% 11% 36% 34% 4	4614
	11th to 20th	Night	16% 8% 22% 41% 13% 1	4613
	21st to end	Night	13% 7% 13% 30% 29% 7%	5069
September	1st to 10th	Night	27% 9% 16% 25% 14% 9%	2100
	11th to 20th	Night	29% 10% 16% 19% 18% 8%	2169
	21st to end	Night	25% 8% 14% 22% 18% 14%	2200
October	1st to 10th	Night	10% 5% 8% 14% 24% 38%	3590
	11th to 20th	Night	15% 5% 10% 19% 17% 34%	3695
	21st to end	Night	10% 2 4 16% 37% 31%	4252
November	1st to 10th	Night	13% 4 6% 16% 31% 30%	2473
	11th to 20th	Night	16% 5% 7% 19% 26% 28%	2730
	21st to end	Night	19% 5% 10% 15% 24% 27%	2730
December	1st to 10th	Night	28% 9% 7% 18% 18% 20%	4380
	11th to 20th	Night	15% 3 5% 21% 32% 24%	4947
	21st to end	Night	13% 4 5% 13% 39% 27%	6374

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	9% 7% 29% 37% 17% 2	330
	11th to 20th	Day	5% 8% 25% 42% 17% 2	330
	21st to end	Day	5% 13% 29% 34% 18% 2	363
February	1st to 10th	Day	6% 10% 22% 31% 24% 6%	330
	11th to 20th	Day	9% 13% 27% 34% 15% 2	330
	21st to end	Day	5% 12% 33% 36% 10% 3	273
March	1st to 10th	Day	8% 10% 32% 34% 15% 1	330
	11th to 20th	Day	8% 16% 33% 28% 11% 4	440
	21st to end	Day	7% 15% 32% 32% 12% 2	594
April	1st to 10th	Day	6% 14% 36% 32% 9% 2	540
	11th to 20th	Day	4 15% 41% 30% 8% 2	532
	21st to end	Day	6% 11% 37% 36% 9% 1	540
May	1st to 10th	Day	4 10% 37% 35% 11% 3	543
	11th to 20th	Day	3 10% 36% 34% 15% 2	568
	21st to end	Day	2 5% 27% 44% 20% 1	727
June	1st to 10th	Day	2 2 17% 41% 34% 5%	780
	11th to 20th	Day	3 2 12% 40% 39% 5%	780
	21st to end	Day	2 2 10% 36% 43% 8%	686
July	1st to 10th	Day	4 2 9% 30% 38% 18%	566
	11th to 20th	Day	3 1 6% 37% 39% 13%	564
	21st to end	Day	2 1 6% 36% 42% 13%	619
August	1st to 10th	Day	3 5% 27% 47% 17%	567
	11th to 20th	Day	3 1 6% 28% 42% 19%	557
	21st to end	Day	2 1 7% 32% 39% 19%	627
September	1st to 10th	Day	5% 2 8% 34% 37% 15%	570
	11th to 20th	Day	6% 4 23% 49% 17%	402
	21st to end	Day	8% 1 8% 25% 40% 19%	330
October	1st to 10th	Day	4 2 9% 27% 43% 14%	330
	11th to 20th	Day	8% 2 11% 32% 34% 13%	330
	21st to end	Day	7% 4 16% 31% 32% 10%	363
November	1st to 10th	Day	5% 4 18% 30% 32% 11%	330
	11th to 20th	Day	8% 7% 19% 27% 31% 8%	330
	21st to end	Day	6% 11% 23% 34% 23% 4	330
December	1st to 10th	Day	8% 6% 18% 34% 28% 5%	330
	11th to 20th	Day	4 8% 24% 37% 23% 4	330
	21st to end	Day	4 7% 22% 42% 21% 4	363
January	1st to 10th	Night	7% 4 21% 51% 17% 1	840
	11th to 20th	Night	8% 4 20% 48% 19%	840
	21st to end	Night	6% 6% 27% 48% 13% 1	924
February	1st to 10th	Night	5% 5% 25% 44% 19% 1	840
	11th to 20th	Night	6% 5% 27% 51% 10% 1	824
	21st to end	Night	5% 7% 31% 49% 7%	692
March	1st to 10th	Night	7% 6% 35% 40% 10% 1	840
	11th to 20th	Night	9% 8% 28% 41% 14% 1	840
	21st to end	Night	4 8% 35% 42% 11%	701
April	1st to 10th	Night	4 9% 33% 45% 9%	630
	11th to 20th	Night	4 8% 38% 44% 6%	623
	21st to end	Night	4 9% 36% 44% 7%	630
May	1st to 10th	Night	4 6% 31% 49% 9%	630
	11th to 20th	Night	5% 6% 30% 48% 10%	621
	21st to end	Night	3 2 30% 51% 13%	683
June	1st to 10th	Night	2 3 18% 57% 20%	630
	11th to 20th	Night	2 1 19% 58% 20%	630
	21st to end	Night	4 2 13% 48% 32% 1	630
July	1st to 10th	Night	6% 1 10% 45% 36% 2	615
	11th to 20th	Night	3 6% 46% 43% 2	612
	21st to end	Night	3 1 6% 40% 48% 2	690
August	1st to 10th	Night	1 1 5% 35% 57% 2	627
	11th to 20th	Night	3 1 5% 32% 54% 4	624
	21st to end	Night	3 1 6% 37% 51% 3	693
September	1st to 10th	Night	5% 3 5% 37% 48% 2	630
	11th to 20th	Night	6% 1 10% 38% 44% 1	609
	21st to end	Night	6% 1 11% 40% 40% 2	600
October	1st to 10th	Night	4 1 12% 45% 37% 1	600
	11th to 20th	Night	7% 1 14% 49% 27% 2	675
	21st to end	Night	5% 3 14% 43% 31% 4	880
November	1st to 10th	Night	7% 1 12% 44% 33% 3	833
	11th to 20th	Night	4 4 14% 49% 27% 1	1050
	21st to end	Night	5% 5% 24% 45% 19% 2	1050
December	1st to 10th	Night	7% 4 17% 50% 21% 1	1050
	11th to 20th	Night	4 4 23% 50% 19% 1	1050
	21st to end	Night	5% 4 21% 51% 18% 1	1039

Page generated at 2026-09-11 03:11:54. Version ac07

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