Solis Lacus Observatory
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Solis Lacus Observatory 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	16% 10% 4 8% 6% 4 5% 5% 5% 7% 30%	83084
	Night	17% 11% 4 8% 6% 3 5% 5% 5% 6% 30%	85688
Transparency	Day	55% 3 10% 20% 10% 1	82789
	Night	56% 3 11% 20% 10% 1	85517
Seeing	Day	26% 13% 28% 19% 10% 4	13933
	Night	24% 12% 27% 27% 10% 1	23326

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	13% 17% 10% 12% 6% 3 5% 4 3 5% 22%	2517
	11th to 20th	Day	14% 15% 8% 15% 7% 5% 6% 4 4 5% 18%	2520
	21st to end	Day	17% 17% 9% 11% 10% 4 4 4 4 5% 16%	3123
February	1st to 10th	Day	16% 13% 5% 12% 8% 5% 5% 5% 5% 5% 19%	1710
	11th to 20th	Day	12% 14% 7% 11% 9% 4 6% 5% 5% 6% 22%	1724
	21st to end	Day	20% 11% 4 11% 9% 4 4 4 4 6% 24%	1570
March	1st to 10th	Day	23% 14% 6% 9% 6% 2 4 3 3 4 25%	3171
	11th to 20th	Day	11% 16% 6% 9% 7% 3 5% 4 5% 6% 28%	3480
	21st to end	Day	18% 12% 4 8% 7% 3 4 4 4 5% 30%	3999
April	1st to 10th	Day	18% 11% 5% 6% 6% 3 5% 4 5% 6% 30%	2270
	11th to 20th	Day	17% 9% 3 7% 6% 3 5% 5% 4 6% 34%	2134
	21st to end	Day	19% 11% 3 7% 6% 3 4 4 3 7% 33%	2160
May	1st to 10th	Day	20% 9% 3 6% 6% 3 6% 5% 5% 6% 31%	2453
	11th to 20th	Day	19% 7% 3 6% 5% 4 5% 5% 7% 8% 32%	2478
	21st to end	Day	15% 6% 2 5% 6% 3 5% 5% 6% 9% 38%	2725
June	1st to 10th	Day	18% 6% 3 6% 5% 4 6% 5% 5% 9% 33%	2520
	11th to 20th	Day	16% 6% 3 5% 6% 4 5% 6% 6% 9% 34%	2520
	21st to end	Day	14% 7% 2 5% 5% 4 7% 6% 5% 10% 35%	2520
July	1st to 10th	Day	10% 5% 3 6% 7% 4 7% 6% 7% 9% 36%	2520
	11th to 20th	Day	10% 5% 3 6% 7% 4 5% 5% 7% 10% 38%	2520
	21st to end	Day	12% 6% 3 6% 6% 4 5% 6% 7% 8% 35%	2744
August	1st to 10th	Day	11% 6% 2 6% 6% 5% 6% 8% 8% 8% 35%	2328
	11th to 20th	Day	14% 7% 3 6% 6% 4 5% 6% 6% 9% 32%	2214
	21st to end	Day	14% 7% 3 6% 6% 4 6% 5% 6% 8% 34%	2376
September	1st to 10th	Day	17% 8% 2 6% 5% 3 4 6% 5% 8% 37%	2160
	11th to 20th	Day	14% 7% 3 5% 6% 2 4 5% 5% 6% 43%	2160
	21st to end	Day	17% 8% 3 5% 6% 4 5% 4 6% 7% 36%	1927
October	1st to 10th	Day	17% 8% 4 7% 6% 4 4 4 6% 8% 33%	1800
	11th to 20th	Day	18% 8% 3 7% 7% 4 4 5% 5% 7% 32%	1800
	21st to end	Day	23% 12% 4 7% 6% 3 4 4 5% 6% 25%	1908
November	1st to 10th	Day	15% 10% 3 7% 5% 3 4 4 4 7% 37%	1671
	11th to 20th	Day	15% 14% 4 8% 7% 3 4 5% 4 5% 30%	1644
	21st to end	Day	17% 15% 5% 8% 7% 3 5% 5% 5% 7% 23%	1520
December	1st to 10th	Day	17% 16% 7% 10% 7% 4 6% 5% 4 6% 19%	1520
	11th to 20th	Day	20% 14% 9% 10% 5% 3 4 3 4 5% 25%	1906
	21st to end	Day	24% 18% 7% 10% 7% 4 4 3 3 4 14%	2772
January	1st to 10th	Night	15% 14% 8% 13% 8% 4 5% 5% 5% 5% 19%	4429
	11th to 20th	Night	13% 14% 7% 12% 10% 5% 5% 4 5% 6% 20%	4440
	21st to end	Night	22% 14% 6% 12% 11% 4 4 4 3 4 16%	4532
February	1st to 10th	Night	16% 11% 5% 10% 8% 4 6% 5% 6% 5% 24%	2470
	11th to 20th	Night	14% 12% 6% 12% 9% 4 6% 6% 5% 5% 21%	2342
	21st to end	Night	19% 10% 4 12% 7% 3 5% 4 5% 6% 25%	1884
March	1st to 10th	Night	20% 13% 6% 9% 5% 3 4 4 4 4 28%	3665
	11th to 20th	Night	14% 17% 6% 7% 7% 3 5% 4 5% 6% 28%	3479
	21st to end	Night	15% 14% 3 8% 6% 4 5% 4 4 5% 31%	3631
April	1st to 10th	Night	20% 11% 3 7% 5% 3 4 5% 4 7% 30%	1900
	11th to 20th	Night	20% 9% 3 6% 5% 2 3 5% 4 7% 35%	1775
	21st to end	Night	19% 9% 4 5% 5% 4 5% 3 5% 5% 37%	1800
May	1st to 10th	Night	21% 10% 3 6% 6% 2 5% 4 5% 6% 32%	1521
	11th to 20th	Night	13% 7% 2 6% 5% 4 5% 6% 8% 8% 36%	1415
	21st to end	Night	12% 6% 3 6% 7% 2 4 5% 5% 8% 42%	1550
June	1st to 10th	Night	16% 7% 3 5% 5% 2 3 5% 6% 8% 40%	1440
	11th to 20th	Night	16% 6% 3 4 5% 3 6% 4 6% 8% 40%	1440
	21st to end	Night	11% 4 2 5% 5% 3 5% 6% 5% 9% 45%	1440
July	1st to 10th	Night	8% 5% 3 6% 5% 4 6% 4 7% 9% 44%	1440
	11th to 20th	Night	10% 5% 1 5% 4 3 5% 5% 6% 10% 45%	1440
	21st to end	Night	12% 5% 3 6% 4 3 5% 6% 6% 8% 41%	1574
August	1st to 10th	Night	8% 5% 3 5% 5% 4 4 6% 7% 8% 45%	1606
	11th to 20th	Night	13% 6% 3 6% 7% 4 5% 5% 6% 7% 37%	1668
	21st to end	Night	13% 5% 2 5% 5% 3 5% 5% 5% 9% 44%	1980
September	1st to 10th	Night	16% 5% 3 5% 5% 3 4 5% 6% 7% 42%	1800
	11th to 20th	Night	13% 5% 3 4 4 2 4 4 5% 7% 49%	1800
	21st to end	Night	15% 6% 3 5% 5% 3 5% 5% 5% 7% 40%	2029
October	1st to 10th	Night	16% 8% 3 7% 6% 3 3 5% 5% 7% 36%	2160
	11th to 20th	Night	19% 8% 3 6% 6% 3 5% 3 5% 7% 36%	2160
	21st to end	Night	24% 12% 3 7% 6% 3 3 3 4 7% 27%	2448
November	1st to 10th	Night	12% 11% 3 7% 5% 3 5% 4 4 6% 38%	2407
	11th to 20th	Night	18% 10% 4 7% 5% 4 5% 5% 5% 6% 32%	2531
	21st to end	Night	14% 13% 6% 6% 6% 4 5% 5% 7% 7% 27%	2660
December	1st to 10th	Night	18% 15% 7% 10% 7% 3 5% 5% 5% 6% 20%	2660
	11th to 20th	Night	20% 13% 5% 9% 6% 3 5% 5% 5% 5% 23%	3288
	21st to end	Night	25% 15% 7% 8% 5% 3 4 5% 4 5% 18%	4884

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% 1 8% 16% 5% 1	2518
	11th to 20th	Day	71% 2 8% 13% 5% 1	2520
	21st to end	Day	73% 2 9% 11% 5%	3123
February	1st to 10th	Day	68% 3 8% 14% 6% 1	1710
	11th to 20th	Day	64% 3 6% 19% 6%	1733
	21st to end	Day	63% 3 8% 17% 8% 1	1570
March	1st to 10th	Day	66% 1 8% 17% 7% 1	3174
	11th to 20th	Day	59% 1 11% 18% 9% 2	3480
	21st to end	Day	58% 1 7% 18% 15% 1	3999
April	1st to 10th	Day	56% 3 6% 23% 10% 2	2270
	11th to 20th	Day	52% 3 9% 20% 14% 2	2134
	21st to end	Day	55% 2 8% 21% 12% 4	2160
May	1st to 10th	Day	54% 3 8% 21% 11% 2	2453
	11th to 20th	Day	51% 3 9% 23% 12% 2	2482
	21st to end	Day	45% 4 15% 23% 12% 1	2725
June	1st to 10th	Day	49% 4 12% 22% 14% 1	2520
	11th to 20th	Day	47% 4 13% 24% 11% 1	2520
	21st to end	Day	45% 5% 12% 26% 11% 1	2520
July	1st to 10th	Day	45% 5% 13% 24% 12% 2	2450
	11th to 20th	Day	41% 4 16% 28% 11%	2445
	21st to end	Day	46% 4 12% 24% 13% 1	2591
August	1st to 10th	Day	44% 4 14% 25% 12% 1	2314
	11th to 20th	Day	47% 4 13% 26% 9%	2214
	21st to end	Day	48% 4 10% 25% 12% 1	2376
September	1st to 10th	Day	47% 4 11% 25% 13% 1	2160
	11th to 20th	Day	42% 3 10% 24% 20% 1	2160
	21st to end	Day	48% 3 11% 24% 13% 2	1927
October	1st to 10th	Day	50% 3 10% 22% 13% 1	1800
	11th to 20th	Day	53% 2 10% 25% 10% 1	1800
	21st to end	Day	62% 2 11% 15% 8% 1	1908
November	1st to 10th	Day	48% 3 12% 22% 13% 2	1671
	11th to 20th	Day	58% 2 10% 19% 10% 2	1644
	21st to end	Day	62% 3 13% 17% 6% 1	1520
December	1st to 10th	Day	69% 2 11% 13% 5%	1520
	11th to 20th	Day	66% 3 14% 13% 4	1906
	21st to end	Day	76% 2 6% 12% 3	2772
January	1st to 10th	Night	68% 2 11% 13% 5%	4429
	11th to 20th	Night	67% 2 10% 15% 5%	4440
	21st to end	Night	75% 2 6% 12% 4 1	4532
February	1st to 10th	Night	62% 3 11% 15% 8%	2470
	11th to 20th	Night	65% 3 9% 15% 7% 1	2344
	21st to end	Night	60% 2 9% 18% 9% 1	1884
March	1st to 10th	Night	61% 2 9% 19% 9%	3675
	11th to 20th	Night	60% 1 11% 21% 6%	3480
	21st to end	Night	57% 2 5% 20% 13% 2	3631
April	1st to 10th	Night	56% 2 9% 19% 11% 2	1900
	11th to 20th	Night	50% 2 12% 20% 16% 1	1775
	21st to end	Night	51% 2 10% 21% 13% 3	1800
May	1st to 10th	Night	55% 3 8% 20% 12% 3	1521
	11th to 20th	Night	44% 5% 10% 24% 15% 2	1416
	21st to end	Night	43% 4 14% 26% 12% 2	1551
June	1st to 10th	Night	42% 4 12% 26% 15%	1440
	11th to 20th	Night	43% 4 16% 25% 11% 2	1440
	21st to end	Night	37% 4 14% 30% 13% 1	1440
July	1st to 10th	Night	38% 5% 15% 25% 15% 2	1400
	11th to 20th	Night	36% 3 16% 29% 15% 1	1392
	21st to end	Night	40% 5% 14% 24% 15% 2	1486
August	1st to 10th	Night	37% 4 17% 29% 11% 1	1596
	11th to 20th	Night	46% 4 15% 25% 10%	1668
	21st to end	Night	39% 3 14% 27% 16% 1	1980
September	1st to 10th	Night	42% 4 12% 26% 14% 1	1800
	11th to 20th	Night	36% 3 11% 30% 19% 1	1800
	21st to end	Night	44% 3 10% 25% 16% 1	2029
October	1st to 10th	Night	49% 3 11% 24% 12% 1	2160
	11th to 20th	Night	50% 3 14% 22% 10% 1	2160
	21st to end	Night	60% 2 11% 17% 9% 1	2448
November	1st to 10th	Night	48% 3 11% 21% 16% 2	2407
	11th to 20th	Night	54% 2 11% 21% 11% 2	2531
	21st to end	Night	55% 3 15% 21% 6%	2660
December	1st to 10th	Night	66% 3 11% 16% 4	2660
	11th to 20th	Night	64% 3 10% 16% 6%	3288
	21st to end	Night	70% 2 10% 15% 2	4884

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	30% 18% 33% 16% 3 1	180
	11th to 20th	Day	42% 21% 24% 11% 3	180
	21st to end	Day	26% 26% 30% 14% 4 1	297
February	1st to 10th	Day	29% 27% 35% 9%	270
	11th to 20th	Day	37% 27% 28% 7% 1	331
	21st to end	Day	37% 21% 27% 11% 3	382
March	1st to 10th	Day	34% 18% 29% 14% 4 1	460
	11th to 20th	Day	35% 19% 27% 13% 5% 1	460
	21st to end	Day	34% 21% 26% 12% 3 2	506
April	1st to 10th	Day	36% 16% 28% 14% 4 1	457
	11th to 20th	Day	30% 20% 26% 13% 7% 4	412
	21st to end	Day	35% 16% 28% 12% 8% 2	420
May	1st to 10th	Day	33% 13% 28% 14% 9% 3	423
	11th to 20th	Day	23% 13% 30% 22% 8% 3	447
	21st to end	Day	20% 8% 30% 22% 15% 4	485
June	1st to 10th	Day	23% 10% 31% 21% 13% 2	450
	11th to 20th	Day	21% 10% 26% 27% 12% 3	450
	21st to end	Day	19% 9% 33% 25% 11% 2	450
July	1st to 10th	Day	17% 3 29% 28% 18% 6%	445
	11th to 20th	Day	13% 6% 26% 32% 18% 5%	444
	21st to end	Day	15% 5% 36% 26% 13% 3	488
August	1st to 10th	Day	15% 5% 24% 26% 22% 8%	446
	11th to 20th	Day	18% 4 23% 29% 17% 9%	439
	21st to end	Day	13% 7% 27% 27% 15% 11%	495
September	1st to 10th	Day	21% 11% 22% 20% 18% 8%	450
	11th to 20th	Day	16% 6% 25% 26% 18% 10%	450
	21st to end	Day	22% 10% 27% 21% 14% 6%	450
October	1st to 10th	Day	26% 10% 24% 20% 14% 7%	450
	11th to 20th	Day	26% 15% 28% 21% 9% 2	450
	21st to end	Day	36% 11% 28% 17% 8%	459
November	1st to 10th	Day	28% 14% 22% 22% 12% 2	365
	11th to 20th	Day	33% 18% 24% 15% 9% 1	304
	21st to end	Day	37% 17% 33% 11% 3	180
December	1st to 10th	Day	33% 22% 31% 9% 3 2	180
	11th to 20th	Day	34% 18% 28% 17% 3	180
	21st to end	Day	38% 20% 30% 11% 2 1	198
January	1st to 10th	Night	27% 21% 31% 18% 2	760
	11th to 20th	Night	29% 17% 27% 23% 4	760
	21st to end	Night	21% 20% 35% 20% 3	836
February	1st to 10th	Night	28% 17% 31% 22% 2	760
	11th to 20th	Night	27% 20% 34% 17% 2	743
	21st to end	Night	34% 15% 29% 18% 4	628
March	1st to 10th	Night	28% 19% 28% 21% 4	760
	11th to 20th	Night	28% 18% 31% 18% 5%	760
	21st to end	Night	26% 19% 28% 20% 6% 1	836
April	1st to 10th	Night	30% 15% 29% 23% 3	760
	11th to 20th	Night	27% 14% 30% 20% 8% 1	711
	21st to end	Night	26% 13% 27% 26% 7%	720
May	1st to 10th	Night	29% 6% 22% 31% 11%	441
	11th to 20th	Night	18% 9% 31% 33% 8% 1	354
	21st to end	Night	14% 6% 27% 37% 15% 1	389
June	1st to 10th	Night	19% 7% 21% 39% 13% 1	360
	11th to 20th	Night	21% 5% 21% 38% 15% 1	360
	21st to end	Night	14% 4 27% 43% 13%	360
July	1st to 10th	Night	11% 2 19% 47% 19% 3	350
	11th to 20th	Night	12% 1 17% 46% 22% 1	348
	21st to end	Night	14% 2 19% 46% 18% 1	394
August	1st to 10th	Night	12% 1 21% 38% 27% 2	532
	11th to 20th	Night	15% 3 13% 35% 29% 5%	604
	21st to end	Night	15% 3 16% 38% 26% 2	792
September	1st to 10th	Night	19% 4 23% 34% 19% 3	720
	11th to 20th	Night	18% 4 17% 32% 24% 5%	720
	21st to end	Night	18% 8% 23% 28% 20% 2	720
October	1st to 10th	Night	23% 8% 22% 27% 18% 2	720
	11th to 20th	Night	25% 10% 25% 31% 8% 1	720
	21st to end	Night	33% 10% 27% 23% 5%	792
November	1st to 10th	Night	21% 12% 28% 30% 9% 1	740
	11th to 20th	Night	27% 14% 30% 21% 7% 1	760
	21st to end	Night	25% 15% 32% 21% 6% 1	760
December	1st to 10th	Night	30% 18% 28% 19% 4	760
	11th to 20th	Night	27% 19% 29% 21% 3	760
	21st to end	Night	30% 17% 32% 18% 3	836

Page generated at 2024-04-07 09:28:14. Version ac07

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