Livingston
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Livingston clear sky chart from 2005-11-06 to 2025-12-18.

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	5% 7% 2 6% 4 4 5% 4 7% 8% 47%	136206
	Night	5% 8% 3 7% 5% 4 5% 4 7% 8% 46%	132194
Transparency	Day	35% 8% 15% 22% 15% 5%	130914
	Night	36% 9% 16% 24% 12% 3	128490
Seeing	Day	14% 18% 31% 23% 11% 2	17016
	Night	10% 16% 32% 30% 11% 1	26554

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 11% 6% 12% 6% 5% 5% 5% 7% 10% 31%	3179
	11th to 20th	Day	1 7% 6% 15% 8% 6% 5% 5% 6% 9% 34%	3520
	21st to end	Day	1 5% 3 7% 5% 4 5% 5% 6% 8% 50%	4510
February	1st to 10th	Day	3 11% 4 10% 7% 7% 6% 6% 7% 9% 30%	1800
	11th to 20th	Day	1 10% 5% 12% 7% 6% 6% 5% 8% 9% 32%	1755
	21st to end	Day	2 10% 3 10% 8% 6% 8% 6% 8% 9% 31%	1536
March	1st to 10th	Day	5% 7% 2 7% 4 4 5% 4 6% 7% 49%	4859
	11th to 20th	Day	2 9% 3 7% 4 5% 6% 5% 8% 9% 42%	5000
	21st to end	Day	5% 12% 4 10% 6% 7% 7% 6% 8% 10% 25%	5486
April	1st to 10th	Day	6% 13% 3 8% 6% 5% 5% 5% 8% 10% 32%	2331
	11th to 20th	Day	6% 11% 4 10% 7% 5% 5% 4 7% 8% 33%	2539
	21st to end	Day	12% 13% 3 8% 5% 5% 5% 4 8% 8% 30%	2600
May	1st to 10th	Day	12% 13% 3 6% 3 3 4 4 6% 8% 37%	5880
	11th to 20th	Day	12% 10% 3 7% 4 5% 5% 5% 8% 9% 32%	6295
	21st to end	Day	10% 6% 2 5% 3 3 5% 4 6% 8% 48%	6925
June	1st to 10th	Day	11% 6% 2 6% 5% 4 6% 5% 8% 9% 37%	2977
	11th to 20th	Day	8% 7% 2 7% 6% 6% 6% 6% 7% 8% 38%	3000
	21st to end	Day	4 3 1 4 4 4 5% 5% 7% 9% 54%	3000
July	1st to 10th	Day	3 2 1 3 3 4 5% 5% 7% 8% 61%	6779
	11th to 20th	Day	4 3 1 3 3 3 4 4 6% 6% 64%	6780
	21st to end	Day	3 3 1 4 4 5% 5% 5% 7% 8% 55%	6534
August	1st to 10th	Day	3 3 1 4 4 4 5% 4 7% 9% 54%	5779
	11th to 20th	Day	3 2 1 3 3 5% 5% 4 6% 7% 60%	5798
	21st to end	Day	7% 4 1 4 3 3 4 4 5% 7% 58%	6434
September	1st to 10th	Day	6% 4 1 4 3 3 3 3 6% 7% 61%	2400
	11th to 20th	Day	7% 5% 2 5% 3 4 5% 4 7% 6% 52%	2223
	21st to end	Day	8% 5% 1 4 3 3 4 4 5% 7% 56%	2200
October	1st to 10th	Day	7% 6% 2 5% 3 3 3 2 4 4 62%	3285
	11th to 20th	Day	7% 7% 2 4 3 3 3 3 3 6% 58%	3250
	21st to end	Day	5% 7% 3 7% 4 5% 6% 5% 6% 7% 45%	3429
November	1st to 10th	Day	5% 8% 3 8% 6% 5% 6% 5% 5% 8% 42%	1729
	11th to 20th	Day	4 8% 3 7% 5% 6% 6% 5% 7% 8% 42%	1680
	21st to end	Day	3 9% 3 5% 5% 4 6% 5% 7% 8% 45%	1680
December	1st to 10th	Day	1 4 3 6% 4 5% 4 4 6% 9% 53%	2700
	11th to 20th	Day	2 7% 2 7% 5% 5% 7% 6% 8% 11% 39%	2836
	21st to end	Day	2 9% 4 9% 5% 6% 7% 6% 7% 8% 38%	3498
January	1st to 10th	Night	1 9% 5% 9% 6% 6% 5% 4 6% 9% 39%	6766
	11th to 20th	Night	1 8% 4 13% 8% 7% 7% 5% 6% 7% 34%	6470
	21st to end	Night	1 6% 2 8% 5% 4 6% 5% 7% 8% 47%	6468
February	1st to 10th	Night	3 12% 6% 12% 7% 5% 7% 6% 9% 7% 28%	2600
	11th to 20th	Night	3 12% 5% 11% 7% 6% 5% 5% 6% 7% 32%	2532
	21st to end	Night	2 10% 5% 10% 7% 6% 5% 5% 7% 7% 35%	2090
March	1st to 10th	Night	2 9% 4 8% 4 4 5% 4 6% 8% 47%	5035
	11th to 20th	Night	5% 11% 3 7% 4 3 4 4 6% 9% 45%	5000
	21st to end	Night	5% 13% 6% 11% 6% 4 5% 4 7% 8% 30%	5489
April	1st to 10th	Night	8% 13% 3 7% 5% 4 5% 4 6% 6% 38%	2067
	11th to 20th	Night	5% 12% 3 8% 5% 5% 6% 5% 7% 8% 35%	1806
	21st to end	Night	13% 13% 3 7% 4 4 4 4 5% 7% 37%	1800
May	1st to 10th	Night	15% 11% 4 7% 4 4 4 3 5% 7% 38%	4100
	11th to 20th	Night	13% 11% 3 7% 5% 5% 4 5% 6% 8% 34%	3617
	21st to end	Night	10% 8% 2 6% 4 4 5% 4 7% 9% 40%	3972
June	1st to 10th	Night	11% 5% 1 7% 5% 6% 6% 5% 7% 8% 38%	1419
	11th to 20th	Night	11% 7% 2 6% 5% 5% 5% 4 8% 8% 41%	1400
	21st to end	Night	5% 4 2 4 4 4 4 3 8% 7% 56%	1400
July	1st to 10th	Night	3 3 2 4 3 4 5% 4 8% 9% 55%	3180
	11th to 20th	Night	4 4 1 3 3 3 4 3 6% 7% 61%	3180
	21st to end	Night	4 3 1 4 4 4 4 4 8% 9% 56%	4306
August	1st to 10th	Night	3 4 1 3 3 4 6% 6% 8% 11% 51%	4033
	11th to 20th	Night	3 2 1 3 4 4 6% 5% 7% 7% 60%	4051
	21st to end	Night	7% 4 2 4 3 4 3 3 5% 6% 59%	4543
September	1st to 10th	Night	5% 5% 2 5% 3 3 4 3 5% 8% 58%	2000
	11th to 20th	Night	8% 6% 2 4 3 3 4 3 7% 9% 51%	2174
	21st to end	Night	10% 6% 2 4 3 3 2 2 4 6% 58%	2200
October	1st to 10th	Night	7% 6% 2 3 2 2 3 2 4 5% 63%	3904
	11th to 20th	Night	8% 9% 2 5% 3 3 3 3 4 7% 54%	3898
	21st to end	Night	6% 8% 2 5% 3 3 5% 4 5% 9% 49%	4367
November	1st to 10th	Night	5% 8% 3 6% 5% 4 4 4 7% 9% 44%	2768
	11th to 20th	Night	4 9% 3 6% 4 5% 4 5% 7% 8% 44%	2940
	21st to end	Night	3 7% 3 7% 4 4 4 5% 8% 9% 47%	2940
December	1st to 10th	Night	1 6% 3 7% 5% 4 4 4 6% 7% 52%	4710
	11th to 20th	Night	2 7% 3 7% 4 4 6% 5% 8% 10% 44%	5511
	21st to end	Night	2 7% 4 8% 4 5% 6% 5% 8% 9% 43%	7458

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	47% 11% 18% 20% 4	3179
	11th to 20th	Day	46% 12% 15% 14% 11% 2	3520
	21st to end	Day	33% 9% 18% 25% 14% 1	4510
February	1st to 10th	Day	55% 10% 13% 16% 6%	1800
	11th to 20th	Day	51% 9% 15% 18% 6% 1	1764
	21st to end	Day	49% 13% 12% 14% 10% 2	1536
March	1st to 10th	Day	34% 7% 13% 25% 15% 5%	4859
	11th to 20th	Day	37% 8% 21% 25% 9%	5000
	21st to end	Day	50% 16% 16% 16% 2	5486
April	1st to 10th	Day	48% 10% 15% 20% 6%	2331
	11th to 20th	Day	50% 10% 16% 18% 6%	2542
	21st to end	Day	52% 9% 15% 18% 6%	2600
May	1st to 10th	Day	43% 9% 12% 26% 9% 1	5880
	11th to 20th	Day	42% 12% 17% 20% 8% 1	6299
	21st to end	Day	32% 10% 19% 29% 10%	6926
June	1st to 10th	Day	41% 11% 18% 21% 7% 1	2977
	11th to 20th	Day	42% 10% 15% 18% 13% 2	3000
	21st to end	Day	24% 9% 16% 25% 21% 5%	3000
July	1st to 10th	Day	19% 6% 10% 26% 26% 12%	6706
	11th to 20th	Day	19% 4 8% 21% 29% 19%	6699
	21st to end	Day	21% 9% 13% 17% 26% 13%	6346
August	1st to 10th	Day	27% 6% 13% 20% 20% 13%	4208
	11th to 20th	Day	24% 5% 10% 28% 26% 6%	4197
	21st to end	Day	23% 5% 8% 27% 26% 10%	4641
September	1st to 10th	Day	24% 4 11% 22% 28% 11%	2400
	11th to 20th	Day	31% 7% 14% 22% 21% 6%	2223
	21st to end	Day	28% 6% 12% 27% 20% 6%	2200
October	1st to 10th	Day	29% 4 8% 18% 32% 9%	3285
	11th to 20th	Day	31% 4 15% 29% 17% 3	3250
	21st to end	Day	39% 6% 15% 27% 11% 2	3429
November	1st to 10th	Day	42% 9% 15% 22% 9% 2	1729
	11th to 20th	Day	41% 11% 18% 21% 7% 1	1680
	21st to end	Day	39% 8% 17% 23% 12% 1	1680
December	1st to 10th	Day	31% 9% 24% 23% 12% 2	2700
	11th to 20th	Day	38% 12% 26% 20% 3 1	2834
	21st to end	Day	44% 8% 11% 23% 8% 6%	3498
January	1st to 10th	Night	43% 10% 18% 25% 5%	6766
	11th to 20th	Night	49% 10% 15% 18% 6% 2	6470
	21st to end	Night	34% 11% 18% 25% 10% 2	6468
February	1st to 10th	Night	54% 11% 15% 14% 6%	2600
	11th to 20th	Night	52% 10% 14% 16% 8% 1	2533
	21st to end	Night	47% 9% 16% 16% 9% 2	2090
March	1st to 10th	Night	34% 9% 13% 27% 14% 4	5035
	11th to 20th	Night	34% 10% 20% 30% 6%	5000
	21st to end	Night	47% 16% 16% 17% 3	5489
April	1st to 10th	Night	46% 9% 16% 21% 7%	2067
	11th to 20th	Night	45% 11% 15% 22% 6%	1806
	21st to end	Night	49% 8% 18% 21% 5%	1800
May	1st to 10th	Night	44% 10% 14% 21% 9% 2	4097
	11th to 20th	Night	44% 12% 15% 21% 7% 1	3618
	21st to end	Night	36% 13% 18% 28% 5%	3972
June	1st to 10th	Night	41% 13% 18% 20% 7%	1419
	11th to 20th	Night	40% 11% 16% 20% 11% 2	1400
	21st to end	Night	24% 9% 15% 28% 19% 5%	1400
July	1st to 10th	Night	23% 6% 13% 30% 25% 2	3145
	11th to 20th	Night	21% 6% 9% 23% 29% 13%	3138
	21st to end	Night	20% 8% 16% 27% 21% 9%	4183
August	1st to 10th	Night	24% 10% 14% 25% 19% 9%	2928
	11th to 20th	Night	24% 8% 12% 29% 22% 5%	2928
	21st to end	Night	21% 5% 9% 30% 28% 7%	3267
September	1st to 10th	Night	25% 6% 11% 21% 26% 11%	2000
	11th to 20th	Night	28% 8% 16% 25% 19% 4	2174
	21st to end	Night	30% 4 12% 27% 23% 4	2200
October	1st to 10th	Night	25% 5% 10% 24% 30% 7%	3904
	11th to 20th	Night	33% 6% 11% 28% 18% 4	3898
	21st to end	Night	34% 6% 15% 25% 17% 3	4367
November	1st to 10th	Night	38% 9% 18% 23% 11% 2	2768
	11th to 20th	Night	40% 8% 20% 24% 8% 1	2940
	21st to end	Night	35% 8% 21% 23% 11% 2	2940
December	1st to 10th	Night	33% 9% 21% 25% 10% 1	4710
	11th to 20th	Night	35% 10% 27% 23% 5%	5512
	21st to end	Night	38% 9% 17% 23% 7% 6%	7458

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	20% 20% 37% 17% 7%	200
	11th to 20th	Day	15% 30% 32% 15% 6% 2	213
	21st to end	Day	15% 22% 45% 12% 4 2	330
February	1st to 10th	Day	23% 27% 36% 11% 4	300
	11th to 20th	Day	16% 29% 36% 14% 4 1	300
	21st to end	Day	22% 28% 32% 14% 3 1	300
March	1st to 10th	Day	16% 28% 36% 16% 3 1	500
	11th to 20th	Day	16% 26% 32% 17% 7% 2	500
	21st to end	Day	20% 23% 33% 17% 5% 1	550
April	1st to 10th	Day	21% 24% 36% 14% 5%	500
	11th to 20th	Day	17% 27% 33% 18% 4	492
	21st to end	Day	22% 23% 28% 16% 8% 2	500
May	1st to 10th	Day	17% 18% 26% 26% 11% 2	503
	11th to 20th	Day	22% 15% 24% 22% 14% 4	722
	21st to end	Day	18% 14% 24% 23% 18% 3	789
June	1st to 10th	Day	13% 14% 26% 25% 18% 4	730
	11th to 20th	Day	15% 21% 29% 23% 10% 1	730
	21st to end	Day	8% 10% 28% 35% 17% 2	730
July	1st to 10th	Day	4 9% 27% 34% 21% 4	721
	11th to 20th	Day	4 9% 31% 34% 20% 1	718
	21st to end	Day	4 9% 32% 33% 18% 4	632
August	1st to 10th	Day	9% 9% 34% 31% 14% 3	527
	11th to 20th	Day	7% 8% 28% 37% 17% 3	517
	21st to end	Day	7% 12% 33% 24% 19% 5%	583
September	1st to 10th	Day	6% 13% 32% 30% 14% 5%	530
	11th to 20th	Day	13% 13% 31% 27% 12% 3	530
	21st to end	Day	15% 17% 27% 24% 15% 3	530
October	1st to 10th	Day	15% 17% 29% 23% 12% 5%	345
	11th to 20th	Day	19% 22% 31% 15% 8% 5%	330
	21st to end	Day	18% 27% 29% 17% 7% 2	363
November	1st to 10th	Day	18% 24% 34% 17% 6% 2	330
	11th to 20th	Day	15% 29% 38% 12% 5%	330
	21st to end	Day	15% 24% 41% 16% 5%	330
December	1st to 10th	Day	19% 28% 32% 15% 5%	330
	11th to 20th	Day	22% 31% 32% 13% 2	261
	21st to end	Day	20% 25% 32% 16% 6%	220
January	1st to 10th	Night	9% 21% 43% 23% 4	1000
	11th to 20th	Night	10% 25% 39% 18% 6% 1	896
	21st to end	Night	7% 23% 48% 17% 5%	880
February	1st to 10th	Night	10% 26% 38% 21% 4	800
	11th to 20th	Night	10% 21% 46% 17% 6% 1	784
	21st to end	Night	12% 21% 38% 22% 5% 1	660
March	1st to 10th	Night	8% 18% 39% 27% 7% 1	800
	11th to 20th	Night	10% 17% 32% 31% 9% 1	800
	21st to end	Night	12% 15% 33% 30% 8% 1	880
April	1st to 10th	Night	15% 15% 37% 25% 7% 1	667
	11th to 20th	Night	12% 15% 36% 31% 6%	593
	21st to end	Night	18% 14% 26% 30% 12% 1	600
May	1st to 10th	Night	17% 11% 24% 33% 15%	600
	11th to 20th	Night	19% 10% 20% 32% 18% 1	591
	21st to end	Night	18% 9% 20% 31% 21% 1	650
June	1st to 10th	Night	13% 9% 19% 38% 20% 1	419
	11th to 20th	Night	12% 11% 29% 38% 9% 1	400
	21st to end	Night	7% 5% 17% 49% 22% 1	400
July	1st to 10th	Night	7% 2 10% 50% 29% 2	390
	11th to 20th	Night	4 5% 19% 53% 19%	388
	21st to end	Night	3 5% 23% 46% 23% 1	642
August	1st to 10th	Night	4 4 20% 52% 20% 1	597
	11th to 20th	Night	5% 4 19% 51% 22% 1	594
	21st to end	Night	7% 6% 21% 43% 22% 1	660
September	1st to 10th	Night	7% 4 21% 45% 21% 2	600
	11th to 20th	Night	9% 7% 19% 41% 21% 3	774
	21st to end	Night	14% 9% 23% 36% 18% 1	800
October	1st to 10th	Night	14% 10% 25% 35% 14% 2	800
	11th to 20th	Night	15% 14% 35% 25% 10% 2	800
	21st to end	Night	10% 19% 35% 27% 8% 1	880
November	1st to 10th	Night	11% 20% 40% 22% 7% 1	923
	11th to 20th	Night	13% 22% 39% 22% 4	1050
	21st to end	Night	7% 21% 44% 25% 4	1050
December	1st to 10th	Night	9% 25% 38% 24% 4 1	1050
	11th to 20th	Night	11% 24% 41% 19% 4	1036
	21st to end	Night	10% 24% 41% 19% 6%	1100

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