Laonil Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Laonil Lake clear sky chart from 2005-11-06 to 2024-01-13.

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	13% 10% 4 8% 7% 4 6% 5% 6% 7% 31%	74546
	Night	10% 11% 5% 9% 8% 4 6% 6% 6% 7% 29%	75208
Transparency	Day	51% 5% 14% 21% 8%	74208
	Night	53% 5% 14% 20% 7% 1	75065
Seeing	Day	17% 12% 32% 26% 11% 3	14719
	Night	16% 9% 30% 30% 12% 2	24099

By Month

Percentage Cloud Cover NW (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	10% 14% 6% 9% 10% 6% 7% 6% 8% 5% 19%	1139
	11th to 20th	Day	8% 14% 6% 10% 11% 5% 8% 7% 7% 7% 17%	1095
	21st to end	Day	10% 17% 6% 12% 10% 2 5% 5% 5% 7% 22%	1448
February	1st to 10th	Day	4 8% 5% 8% 11% 5% 8% 8% 11% 8% 24%	1440
	11th to 20th	Day	6% 11% 6% 10% 6% 6% 7% 6% 7% 8% 28%	1454
	21st to end	Day	4 7% 7% 11% 11% 6% 8% 6% 5% 6% 31%	1403
March	1st to 10th	Day	8% 12% 4 8% 7% 5% 6% 5% 5% 7% 33%	1800
	11th to 20th	Day	8% 11% 4 9% 8% 3 4 5% 6% 8% 33%	1834
	21st to end	Day	9% 11% 5% 7% 6% 5% 5% 6% 7% 8% 33%	2376
April	1st to 10th	Day	8% 9% 5% 8% 8% 4 6% 5% 5% 6% 37%	2160
	11th to 20th	Day	10% 9% 5% 7% 8% 4 5% 5% 6% 8% 34%	2321
	21st to end	Day	9% 10% 4 8% 7% 4 5% 6% 6% 7% 33%	2520
May	1st to 10th	Day	14% 10% 4 7% 6% 3 6% 4 5% 7% 33%	2551
	11th to 20th	Day	11% 7% 3 5% 6% 3 5% 5% 5% 8% 43%	2679
	21st to end	Day	16% 9% 3 6% 5% 3 4 5% 5% 8% 38%	3111
June	1st to 10th	Day	17% 8% 3 7% 6% 3 5% 5% 5% 7% 33%	2880
	11th to 20th	Day	21% 9% 4 7% 6% 4 5% 6% 6% 7% 26%	2880
	21st to end	Day	20% 7% 3 6% 7% 4 6% 5% 6% 8% 29%	2880
July	1st to 10th	Day	14% 5% 3 5% 6% 4 7% 5% 6% 9% 36%	2880
	11th to 20th	Day	14% 6% 3 6% 6% 4 6% 5% 6% 8% 36%	2880
	21st to end	Day	13% 7% 2 6% 6% 4 6% 6% 6% 8% 34%	3068
August	1st to 10th	Day	12% 6% 2 5% 6% 4 6% 6% 6% 8% 39%	2507
	11th to 20th	Day	12% 7% 3 7% 5% 4 5% 6% 6% 8% 36%	2477
	21st to end	Day	16% 7% 4 6% 6% 4 5% 5% 6% 9% 33%	2651
September	1st to 10th	Day	12% 9% 3 8% 7% 3 5% 6% 5% 7% 34%	2160
	11th to 20th	Day	17% 11% 3 8% 7% 3 5% 5% 5% 8% 29%	2129
	21st to end	Day	15% 11% 3 5% 4 3 5% 4 5% 7% 37%	1972
October	1st to 10th	Day	20% 14% 5% 7% 5% 3 3 4 4 6% 30%	1800
	11th to 20th	Day	14% 16% 7% 10% 6% 3 4 3 5% 5% 26%	1626
	21st to end	Day	16% 23% 8% 13% 6% 3 3 4 4 3 17%	1746
November	1st to 10th	Day	17% 17% 8% 14% 9% 4 5% 2 4 5% 15%	1397
	11th to 20th	Day	12% 13% 6% 15% 12% 6% 7% 4 5% 4 16%	1330
	21st to end	Day	11% 12% 9% 15% 12% 4 8% 5% 5% 6% 13%	1283
December	1st to 10th	Day	5% 10% 6% 12% 16% 6% 8% 7% 6% 6% 16%	1140
	11th to 20th	Day	10% 12% 5% 11% 12% 6% 6% 5% 7% 6% 21%	1439
	21st to end	Day	6% 8% 3 8% 8% 5% 6% 7% 8% 8% 34%	2090
January	1st to 10th	Night	8% 13% 5% 11% 11% 6% 7% 7% 8% 6% 17%	3026
	11th to 20th	Night	8% 13% 6% 10% 10% 5% 7% 6% 6% 10% 18%	2927
	21st to end	Night	10% 15% 6% 11% 9% 4 7% 6% 7% 6% 18%	2907
February	1st to 10th	Night	6% 9% 4 10% 7% 5% 8% 7% 9% 11% 24%	2520
	11th to 20th	Night	6% 10% 5% 8% 7% 4 8% 8% 7% 8% 29%	2407
	21st to end	Night	3 8% 5% 9% 8% 6% 8% 8% 9% 8% 28%	1852
March	1st to 10th	Night	7% 12% 5% 8% 8% 5% 6% 6% 6% 6% 30%	2160
	11th to 20th	Night	9% 11% 5% 8% 8% 3 4 4 5% 7% 33%	2123
	21st to end	Night	7% 10% 4 7% 6% 4 6% 6% 6% 7% 37%	1980
April	1st to 10th	Night	9% 10% 4 7% 7% 5% 5% 5% 5% 7% 37%	1800
	11th to 20th	Night	10% 11% 4 8% 6% 4 5% 5% 5% 7% 35%	1589
	21st to end	Night	9% 9% 4 8% 7% 3 5% 4 5% 6% 39%	1440
May	1st to 10th	Night	14% 10% 4 6% 5% 4 6% 6% 5% 7% 34%	1408
	11th to 20th	Night	10% 7% 2 5% 6% 3 5% 4 7% 7% 44%	1215
	21st to end	Night	16% 6% 2 5% 5% 3 4 7% 6% 7% 38%	1164
June	1st to 10th	Night	14% 8% 2 7% 7% 4 6% 5% 4 9% 36%	1080
	11th to 20th	Night	16% 8% 4 7% 6% 4 5% 5% 4 7% 34%	1080
	21st to end	Night	15% 7% 3 7% 4 3 5% 6% 6% 7% 36%	1080
July	1st to 10th	Night	13% 6% 2 6% 5% 4 5% 5% 7% 9% 38%	1080
	11th to 20th	Night	11% 5% 3 6% 6% 4 5% 6% 6% 9% 40%	1080
	21st to end	Night	14% 6% 2 4 6% 3 5% 5% 5% 10% 40%	1246
August	1st to 10th	Night	11% 4 2 5% 4 4 4 5% 6% 9% 46%	1432
	11th to 20th	Night	11% 5% 2 4 5% 2 5% 6% 6% 9% 43%	1424
	21st to end	Night	15% 6% 2 7% 6% 4 6% 5% 6% 8% 35%	1701
September	1st to 10th	Night	13% 7% 3 6% 6% 4 5% 5% 6% 8% 38%	1800
	11th to 20th	Night	17% 8% 3 6% 5% 4 5% 5% 5% 7% 34%	1831
	21st to end	Night	13% 7% 3 6% 4 2 5% 5% 6% 7% 41%	1984
October	1st to 10th	Night	18% 13% 3 6% 5% 3 5% 4 5% 7% 33%	2160
	11th to 20th	Night	15% 16% 4 9% 6% 3 4 4 4 6% 29%	2316
	21st to end	Night	15% 18% 7% 11% 7% 3 4 5% 5% 6% 19%	2610
November	1st to 10th	Night	16% 18% 7% 11% 10% 4 5% 3 4 5% 16%	2680
	11th to 20th	Night	12% 14% 6% 11% 13% 8% 7% 4 3 5% 17%	2850
	21st to end	Night	8% 14% 7% 12% 12% 6% 8% 6% 5% 5% 17%	2897
December	1st to 10th	Night	6% 12% 6% 12% 14% 7% 9% 7% 6% 4 15%	3040
	11th to 20th	Night	8% 13% 7% 14% 10% 4 6% 6% 7% 6% 19%	3753
	21st to end	Night	4 9% 4 9% 8% 5% 6% 6% 6% 8% 35%	5566

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	63% 4 13% 15% 5%	1139
	11th to 20th	Day	64% 4 9% 17% 5%	1095
	21st to end	Day	62% 4 7% 17% 10%	1448
February	1st to 10th	Day	52% 5% 14% 20% 9%	1440
	11th to 20th	Day	52% 4 12% 21% 11%	1462
	21st to end	Day	53% 4 13% 21% 8%	1403
March	1st to 10th	Day	51% 4 12% 23% 9% 1	1800
	11th to 20th	Day	48% 5% 15% 23% 9% 1	1835
	21st to end	Day	46% 5% 13% 26% 8% 1	2376
April	1st to 10th	Day	46% 6% 10% 22% 15%	2160
	11th to 20th	Day	47% 5% 12% 25% 10% 1	2321
	21st to end	Day	48% 4 13% 24% 10% 1	2520
May	1st to 10th	Day	49% 5% 9% 25% 11% 1	2551
	11th to 20th	Day	39% 5% 11% 26% 17% 3	2683
	21st to end	Day	45% 4 10% 25% 15% 1	3112
June	1st to 10th	Day	50% 5% 10% 22% 12% 1	2880
	11th to 20th	Day	56% 5% 12% 19% 7%	2880
	21st to end	Day	52% 6% 13% 21% 8%	2880
July	1st to 10th	Day	43% 7% 16% 26% 9%	2801
	11th to 20th	Day	44% 6% 18% 28% 5%	2793
	21st to end	Day	47% 6% 19% 24% 4	2897
August	1st to 10th	Day	41% 7% 21% 25% 5%	2491
	11th to 20th	Day	43% 7% 23% 23% 4	2477
	21st to end	Day	47% 7% 25% 18% 3	2651
September	1st to 10th	Day	48% 6% 20% 18% 8%	2160
	11th to 20th	Day	54% 5% 20% 18% 3	2129
	21st to end	Day	47% 5% 21% 24% 4	1972
October	1st to 10th	Day	57% 4 14% 20% 6%	1800
	11th to 20th	Day	59% 5% 13% 18% 4	1626
	21st to end	Day	73% 4 8% 12% 3	1746
November	1st to 10th	Day	75% 3 10% 8% 3	1397
	11th to 20th	Day	70% 5% 11% 12% 3	1330
	21st to end	Day	72% 3 11% 10% 3	1283
December	1st to 10th	Day	64% 6% 13% 12% 5%	1140
	11th to 20th	Day	63% 5% 15% 11% 5%	1440
	21st to end	Day	44% 5% 14% 22% 14% 1	2090
January	1st to 10th	Night	64% 5% 13% 15% 4	3026
	11th to 20th	Night	61% 5% 12% 17% 6%	2927
	21st to end	Night	65% 4 8% 15% 8%	2907
February	1st to 10th	Night	52% 4 13% 20% 10% 1	2520
	11th to 20th	Night	52% 4 15% 21% 8%	2409
	21st to end	Night	49% 5% 14% 23% 8%	1852
March	1st to 10th	Night	53% 5% 11% 21% 8% 2	2160
	11th to 20th	Night	51% 3 11% 23% 11% 1	2123
	21st to end	Night	43% 6% 13% 27% 9% 1	1980
April	1st to 10th	Night	46% 4 12% 21% 16% 2	1800
	11th to 20th	Night	48% 6% 9% 22% 14% 2	1589
	21st to end	Night	46% 3 9% 28% 11% 2	1440
May	1st to 10th	Night	48% 5% 8% 25% 14%	1408
	11th to 20th	Night	38% 4 10% 25% 18% 4	1215
	21st to end	Night	43% 7% 10% 26% 13% 2	1164
June	1st to 10th	Night	46% 5% 12% 22% 14% 1	1080
	11th to 20th	Night	49% 5% 15% 22% 8% 1	1080
	21st to end	Night	45% 6% 15% 26% 7% 1	1080
July	1st to 10th	Night	41% 5% 15% 28% 10% 1	1050
	11th to 20th	Night	39% 5% 19% 32% 5%	1044
	21st to end	Night	40% 6% 21% 25% 7%	1177
August	1st to 10th	Night	33% 7% 22% 31% 6%	1424
	11th to 20th	Night	36% 7% 26% 25% 6%	1424
	21st to end	Night	46% 6% 21% 23% 3	1701
September	1st to 10th	Night	43% 5% 19% 24% 7% 1	1800
	11th to 20th	Night	49% 5% 19% 22% 5%	1831
	21st to end	Night	41% 4 18% 28% 8% 1	1984
October	1st to 10th	Night	52% 5% 15% 23% 5%	2160
	11th to 20th	Night	58% 4 14% 19% 5%	2316
	21st to end	Night	66% 4 12% 13% 4	2610
November	1st to 10th	Night	72% 4 10% 12% 2	2680
	11th to 20th	Night	70% 5% 12% 11% 2	2850
	21st to end	Night	67% 5% 13% 12% 3	2897
December	1st to 10th	Night	67% 5% 11% 13% 4	3040
	11th to 20th	Night	63% 4 14% 13% 5%	3751
	21st to end	Night	46% 4 15% 24% 11% 1	5566

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	13% 12% 45% 23% 7%	180
	11th to 20th	Day	13% 9% 42% 25% 8% 2	165
	21st to end	Day	14% 13% 30% 29% 12% 1	204
February	1st to 10th	Day	8% 15% 40% 25% 9% 4	240
	11th to 20th	Day	10% 15% 36% 28% 11% 1	240
	21st to end	Day	2 15% 34% 35% 11% 3	198
March	1st to 10th	Day	14% 12% 32% 29% 13% 2	240
	11th to 20th	Day	9% 11% 42% 27% 12% 1	269
	21st to end	Day	14% 15% 36% 24% 10% 1	462
April	1st to 10th	Day	14% 14% 38% 24% 8% 2	420
	11th to 20th	Day	14% 12% 36% 25% 11% 1	554
	21st to end	Day	15% 12% 34% 25% 13% 2	600
May	1st to 10th	Day	20% 11% 31% 27% 10% 1	603
	11th to 20th	Day	15% 16% 30% 24% 12% 2	625
	21st to end	Day	20% 11% 26% 29% 12% 2	679
June	1st to 10th	Day	21% 11% 30% 22% 11% 3	630
	11th to 20th	Day	27% 12% 28% 23% 8% 2	630
	21st to end	Day	21% 10% 25% 27% 13% 4	630
July	1st to 10th	Day	15% 11% 29% 29% 13% 3	621
	11th to 20th	Day	16% 7% 27% 30% 16% 4	618
	21st to end	Day	16% 6% 26% 27% 21% 4	684
August	1st to 10th	Day	14% 7% 26% 30% 17% 5%	626
	11th to 20th	Day	14% 10% 28% 26% 16% 5%	615
	21st to end	Day	19% 9% 30% 30% 9% 3	664
September	1st to 10th	Day	20% 18% 36% 20% 6%	450
	11th to 20th	Day	21% 9% 36% 24% 9% 2	419
	21st to end	Day	20% 16% 35% 21% 7%	270
October	1st to 10th	Day	26% 12% 33% 20% 8% 1	270
	11th to 20th	Day	25% 18% 30% 17% 9% 1	270
	21st to end	Day	27% 13% 31% 19% 8% 3	297
November	1st to 10th	Day	16% 13% 37% 21% 12%	270
	11th to 20th	Day	19% 17% 37% 23% 3	270
	21st to end	Day	19% 16% 38% 19% 7% 1	248
December	1st to 10th	Day	12% 16% 31% 32% 7% 3	180
	11th to 20th	Day	14% 11% 46% 24% 4 1	180
	21st to end	Day	8% 7% 30% 36% 14% 5%	198
January	1st to 10th	Night	14% 11% 33% 31% 11% 1	950
	11th to 20th	Night	14% 9% 38% 29% 8% 2	915
	21st to end	Night	18% 12% 33% 27% 8% 2	990
February	1st to 10th	Night	9% 10% 39% 28% 11% 3	900
	11th to 20th	Night	11% 9% 33% 30% 13% 3	839
	21st to end	Night	6% 9% 33% 33% 17% 2	592
March	1st to 10th	Night	10% 8% 29% 35% 16% 2	720
	11th to 20th	Night	16% 10% 35% 28% 11% 1	714
	21st to end	Night	12% 8% 30% 29% 18% 2	594
April	1st to 10th	Night	14% 7% 29% 33% 14% 2	540
	11th to 20th	Night	16% 7% 32% 31% 14% 1	533
	21st to end	Night	14% 9% 31% 33% 11% 1	540
May	1st to 10th	Night	19% 9% 30% 31% 10% 1	540
	11th to 20th	Night	15% 9% 29% 33% 13% 1	506
	21st to end	Night	19% 6% 28% 32% 14% 2	389
June	1st to 10th	Night	19% 6% 26% 32% 16% 1	360
	11th to 20th	Night	20% 7% 26% 31% 14% 1	360
	21st to end	Night	17% 4 23% 37% 17% 2	360
July	1st to 10th	Night	15% 6% 22% 39% 17% 1	350
	11th to 20th	Night	14% 5% 22% 34% 23% 3	348
	21st to end	Night	16% 4 18% 35% 23% 5%	414
August	1st to 10th	Night	13% 6% 22% 32% 24% 4	537
	11th to 20th	Night	13% 8% 22% 33% 20% 3	534
	21st to end	Night	17% 6% 26% 36% 14% 1	594
September	1st to 10th	Night	18% 8% 26% 31% 15% 1	540
	11th to 20th	Night	21% 6% 27% 35% 10%	540
	21st to end	Night	17% 9% 32% 33% 8% 1	544
October	1st to 10th	Night	26% 8% 30% 26% 9% 1	720
	11th to 20th	Night	27% 10% 29% 23% 9% 2	876
	21st to end	Night	26% 12% 28% 23% 9% 2	990
November	1st to 10th	Night	25% 11% 32% 22% 9% 1	925
	11th to 20th	Night	20% 12% 34% 27% 7% 1	950
	21st to end	Night	16% 12% 37% 26% 8% 1	950
December	1st to 10th	Night	13% 11% 32% 31% 11% 2	950
	11th to 20th	Night	14% 10% 36% 26% 11% 3	950
	21st to end	Night	12% 9% 27% 36% 15% 2	1045

Page generated at 2024-01-10 18:35:21. Version ac07

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