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 2024-11-12.

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	11% 10% 4 9% 6% 5% 5% 4 6% 7% 31%	105950
	Night	9% 11% 4 11% 7% 6% 6% 4 6% 7% 29%	101785
Transparency	Day	50% 5% 15% 22% 7%	105672
	Night	53% 5% 14% 21% 7%	101710
Seeing	Day	17% 12% 32% 26% 11% 3	15937
	Night	16% 9% 31% 30% 12% 2	25113

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	6% 13% 6% 17% 13% 10% 8% 4 6% 3 15%	1899
	11th to 20th	Day	5% 12% 6% 15% 13% 10% 10% 7% 7% 5% 9%	1882
	21st to end	Day	7% 17% 5% 19% 8% 5% 5% 4 5% 6% 18%	2546
February	1st to 10th	Day	4 9% 6% 9% 10% 7% 7% 7% 10% 8% 23%	1520
	11th to 20th	Day	5% 11% 6% 11% 6% 6% 6% 5% 7% 8% 29%	1537
	21st to end	Day	3 8% 5% 13% 8% 7% 8% 5% 5% 6% 30%	1488
March	1st to 10th	Day	5% 11% 4 9% 6% 7% 7% 5% 5% 7% 35%	3130
	11th to 20th	Day	5% 8% 4 11% 9% 5% 7% 4 7% 9% 31%	3245
	21st to end	Day	5% 10% 3 9% 5% 5% 5% 3 5% 7% 42%	4165
April	1st to 10th	Day	8% 10% 4 10% 6% 6% 6% 4 6% 6% 36%	2280
	11th to 20th	Day	10% 10% 4 8% 7% 5% 5% 4 6% 7% 33%	2452
	21st to end	Day	9% 10% 4 9% 6% 5% 5% 5% 7% 7% 34%	2660
May	1st to 10th	Day	12% 12% 4 9% 6% 5% 5% 4 7% 8% 28%	4489
	11th to 20th	Day	23% 9% 3 6% 4 4 4 4 5% 7% 32%	4755
	21st to end	Day	17% 14% 4 9% 5% 4 4 4 5% 7% 28%	5509
June	1st to 10th	Day	18% 10% 3 8% 5% 4 5% 4 5% 6% 32%	3040
	11th to 20th	Day	20% 10% 3 8% 5% 5% 5% 4 6% 7% 25%	3040
	21st to end	Day	19% 8% 3 7% 6% 5% 5% 4 6% 8% 30%	3040
July	1st to 10th	Day	9% 5% 2 6% 5% 6% 6% 5% 8% 10% 40%	5060
	11th to 20th	Day	8% 4 2 5% 4 5% 5% 4 6% 9% 48%	5060
	21st to end	Day	11% 7% 2 7% 6% 6% 6% 5% 7% 9% 35%	5356
August	1st to 10th	Day	7% 4 2 5% 4 5% 6% 5% 7% 11% 44%	4412
	11th to 20th	Day	11% 7% 3 8% 5% 5% 5% 4 6% 7% 38%	4343
	21st to end	Day	12% 6% 3 7% 5% 5% 6% 5% 7% 9% 35%	4646
September	1st to 10th	Day	12% 9% 3 10% 5% 4 6% 4 6% 8% 34%	2280
	11th to 20th	Day	17% 11% 3 9% 5% 5% 5% 4 5% 8% 28%	2247
	21st to end	Day	15% 12% 2 6% 4 5% 5% 4 5% 6% 36%	2081
October	1st to 10th	Day	14% 11% 4 9% 5% 5% 6% 5% 6% 7% 27%	3170
	11th to 20th	Day	12% 15% 5% 10% 5% 5% 5% 4 6% 7% 27%	2838
	21st to end	Day	15% 22% 8% 12% 5% 4 4 3 4 4 18%	3019
November	1st to 10th	Day	16% 19% 7% 16% 8% 6% 4 2 4 5% 14%	1472
	11th to 20th	Day	12% 14% 6% 17% 10% 8% 5% 4 5% 4 16%	1337
	21st to end	Day	10% 14% 9% 16% 10% 6% 7% 4 5% 6% 13%	1283
December	1st to 10th	Day	5% 12% 5% 16% 13% 7% 8% 5% 6% 7% 16%	1140
	11th to 20th	Day	10% 13% 5% 12% 11% 7% 5% 4 7% 6% 21%	1439
	21st to end	Day	5% 8% 3 9% 7% 7% 5% 5% 8% 8% 34%	2090
January	1st to 10th	Night	5% 12% 5% 18% 12% 10% 9% 6% 7% 5% 12%	5046
	11th to 20th	Night	5% 10% 5% 19% 14% 9% 8% 5% 7% 7% 11%	5016
	21st to end	Night	7% 16% 7% 15% 7% 5% 5% 4 6% 7% 20%	5112
February	1st to 10th	Night	6% 10% 4 11% 7% 7% 8% 5% 8% 10% 24%	2660
	11th to 20th	Night	6% 10% 4 10% 7% 7% 6% 7% 7% 7% 29%	2545
	21st to end	Night	2 8% 5% 10% 8% 8% 7% 7% 9% 8% 29%	1965
March	1st to 10th	Night	6% 13% 4 8% 6% 7% 6% 4 5% 7% 34%	3734
	11th to 20th	Night	7% 10% 3 10% 7% 6% 5% 4 6% 9% 33%	3723
	21st to end	Night	5% 9% 3 8% 5% 5% 4 4 5% 6% 47%	3477
April	1st to 10th	Night	9% 10% 4 9% 6% 6% 5% 4 5% 7% 35%	1900
	11th to 20th	Night	10% 12% 4 8% 5% 6% 5% 4 5% 6% 34%	1677
	21st to end	Night	9% 9% 3 10% 6% 4 5% 3 5% 6% 39%	1520
May	1st to 10th	Night	12% 10% 3 9% 6% 6% 7% 5% 6% 7% 29%	2480
	11th to 20th	Night	19% 8% 2 6% 5% 5% 6% 5% 7% 7% 32%	2147
	21st to end	Night	14% 13% 3 9% 6% 4 4 4 6% 7% 29%	2066
June	1st to 10th	Night	16% 9% 2 7% 7% 5% 5% 4 4 8% 34%	1140
	11th to 20th	Night	15% 10% 3 8% 5% 6% 4 4 4 7% 34%	1140
	21st to end	Night	15% 8% 3 8% 4 4 4 5% 6% 6% 37%	1140
July	1st to 10th	Night	9% 4 1 5% 5% 5% 6% 6% 8% 11% 39%	1900
	11th to 20th	Night	7% 4 2 5% 5% 4 5% 4 6% 9% 48%	1900
	21st to end	Night	10% 5% 2 6% 4 4 5% 4 7% 11% 41%	2195
August	1st to 10th	Night	7% 3 2 4 3 4 5% 5% 7% 11% 48%	2528
	11th to 20th	Night	10% 6% 3 7% 5% 4 5% 4 5% 8% 43%	2496
	21st to end	Night	10% 6% 2 7% 4 5% 5% 5% 7% 10% 40%	3017
September	1st to 10th	Night	12% 6% 3 7% 5% 5% 5% 4 6% 8% 39%	1900
	11th to 20th	Night	17% 9% 3 7% 4 5% 5% 4 5% 7% 33%	1933
	21st to end	Night	13% 8% 3 6% 4 4 5% 4 6% 7% 41%	2095
October	1st to 10th	Night	14% 12% 3 7% 4 4 4 4 5% 7% 37%	3800
	11th to 20th	Night	11% 14% 4 10% 6% 5% 5% 3 5% 6% 31%	4059
	21st to end	Night	15% 19% 7% 11% 5% 4 4 4 5% 6% 20%	4527
November	1st to 10th	Night	15% 19% 7% 13% 8% 6% 4 3 5% 5% 16%	2825
	11th to 20th	Night	12% 15% 6% 14% 11% 9% 6% 3 4 4 17%	2866
	21st to end	Night	8% 15% 6% 14% 10% 8% 7% 4 6% 5% 17%	2897
December	1st to 10th	Night	6% 14% 5% 14% 12% 10% 8% 5% 6% 5% 15%	3040
	11th to 20th	Night	8% 14% 6% 16% 8% 6% 5% 5% 7% 6% 19%	3753
	21st to end	Night	4 10% 4 11% 6% 6% 5% 4 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	73% 3 10% 11% 3	1899
	11th to 20th	Day	74% 3 10% 10% 3	1900
	21st to end	Day	66% 3 11% 14% 6%	2546
February	1st to 10th	Day	53% 4 14% 20% 8%	1520
	11th to 20th	Day	50% 4 13% 22% 11%	1545
	21st to end	Day	53% 4 13% 21% 9%	1488
March	1st to 10th	Day	49% 4 13% 27% 6% 1	3130
	11th to 20th	Day	46% 8% 15% 20% 11%	3246
	21st to end	Day	39% 5% 8% 22% 24% 1	4165
April	1st to 10th	Day	47% 6% 10% 22% 14%	2280
	11th to 20th	Day	48% 5% 12% 25% 10% 1	2452
	21st to end	Day	47% 4 12% 26% 10% 1	2660
May	1st to 10th	Day	52% 5% 11% 24% 8% 1	4489
	11th to 20th	Day	51% 4 12% 20% 11% 2	4759
	21st to end	Day	55% 5% 15% 16% 9%	5510
June	1st to 10th	Day	52% 5% 10% 22% 11% 1	3040
	11th to 20th	Day	56% 5% 13% 19% 7% 1	3040
	21st to end	Day	51% 6% 13% 21% 9%	3040
July	1st to 10th	Day	35% 7% 21% 30% 7%	4981
	11th to 20th	Day	31% 6% 18% 37% 7%	4973
	21st to end	Day	44% 7% 23% 22% 3	5186
August	1st to 10th	Day	32% 7% 24% 32% 5%	4396
	11th to 20th	Day	43% 6% 22% 25% 4	4385
	21st to end	Day	43% 7% 23% 23% 4	4645
September	1st to 10th	Day	48% 6% 19% 18% 8%	2280
	11th to 20th	Day	54% 5% 19% 18% 3	2247
	21st to end	Day	48% 4 20% 23% 4	2081
October	1st to 10th	Day	54% 5% 16% 21% 4	3170
	11th to 20th	Day	55% 5% 16% 19% 4	2838
	21st to end	Day	70% 6% 10% 12% 2	3019
November	1st to 10th	Day	75% 3 11% 8% 3	1472
	11th to 20th	Day	70% 5% 11% 12% 3	1337
	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	71% 4 12% 11% 2	5046
	11th to 20th	Night	72% 3 10% 12% 3	5060
	21st to end	Night	63% 3 17% 12% 6%	5112
February	1st to 10th	Night	53% 4 13% 19% 10% 1	2660
	11th to 20th	Night	52% 4 15% 21% 8%	2547
	21st to end	Night	48% 5% 14% 23% 9%	1965
March	1st to 10th	Night	49% 4 12% 26% 7% 1	3734
	11th to 20th	Night	46% 7% 12% 25% 10%	3723
	21st to end	Night	38% 5% 10% 22% 24% 1	3477
April	1st to 10th	Night	47% 4 12% 20% 16% 2	1900
	11th to 20th	Night	48% 6% 9% 21% 14% 2	1677
	21st to end	Night	46% 3 9% 28% 12% 2	1520
May	1st to 10th	Night	51% 5% 11% 21% 10%	2480
	11th to 20th	Night	49% 6% 11% 21% 11% 2	2147
	21st to end	Night	53% 6% 15% 18% 8% 1	2066
June	1st to 10th	Night	47% 5% 11% 22% 14% 1	1140
	11th to 20th	Night	49% 6% 15% 21% 8% 1	1140
	21st to end	Night	45% 6% 14% 26% 8% 1	1140
July	1st to 10th	Night	35% 7% 19% 31% 7%	1870
	11th to 20th	Night	31% 6% 13% 46% 4	1864
	21st to end	Night	35% 7% 29% 26% 4	2126
August	1st to 10th	Night	27% 7% 23% 35% 8%	2520
	11th to 20th	Night	38% 7% 23% 25% 7%	2520
	21st to end	Night	37% 6% 24% 30% 2	3017
September	1st to 10th	Night	42% 5% 20% 25% 7% 1	1900
	11th to 20th	Night	49% 5% 19% 23% 5%	1933
	21st to end	Night	41% 4 18% 28% 8% 1	2095
October	1st to 10th	Night	47% 4 14% 28% 6%	3800
	11th to 20th	Night	54% 4 14% 23% 5%	4059
	21st to end	Night	64% 5% 15% 13% 2	4527
November	1st to 10th	Night	71% 4 11% 12% 2	2825
	11th to 20th	Night	70% 5% 12% 11% 2	2866
	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% 10% 42% 23% 9% 2	180
	21st to end	Day	13% 13% 33% 29% 11% 1	229
February	1st to 10th	Day	7% 14% 39% 26% 10% 4	270
	11th to 20th	Day	9% 15% 37% 29% 10% 1	270
	21st to end	Day	4 16% 35% 33% 10% 3	225
March	1st to 10th	Day	13% 13% 33% 27% 12% 2	270
	11th to 20th	Day	9% 12% 41% 26% 11% 1	301
	21st to end	Day	13% 14% 34% 26% 11% 1	506
April	1st to 10th	Day	14% 15% 37% 23% 8% 2	460
	11th to 20th	Day	16% 12% 36% 24% 10% 1	602
	21st to end	Day	14% 12% 33% 26% 13% 2	650
May	1st to 10th	Day	20% 11% 31% 25% 11% 2	653
	11th to 20th	Day	18% 15% 30% 23% 11% 2	675
	21st to end	Day	20% 12% 27% 28% 11% 2	734
June	1st to 10th	Day	23% 12% 29% 22% 10% 3	680
	11th to 20th	Day	27% 11% 29% 22% 8% 3	680
	21st to end	Day	20% 11% 25% 26% 14% 4	680
July	1st to 10th	Day	14% 11% 29% 30% 13% 3	671
	11th to 20th	Day	15% 7% 26% 30% 17% 5%	668
	21st to end	Day	16% 7% 26% 28% 19% 4	739
August	1st to 10th	Day	13% 8% 27% 30% 17% 6%	676
	11th to 20th	Day	14% 10% 28% 27% 16% 6%	665
	21st to end	Day	18% 9% 30% 30% 9% 3	717
September	1st to 10th	Day	20% 17% 36% 21% 6%	490
	11th to 20th	Day	21% 9% 35% 24% 8% 2	457
	21st to end	Day	20% 18% 34% 20% 7%	300
October	1st to 10th	Day	25% 14% 33% 20% 7% 1	300
	11th to 20th	Day	24% 19% 31% 16% 8% 1	300
	21st to end	Day	27% 14% 31% 18% 8% 2	330
November	1st to 10th	Day	17% 14% 35% 21% 13%	300
	11th to 20th	Day	19% 17% 37% 23% 3	273
	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% 10% 38% 29% 8% 1	950
	21st to end	Night	18% 12% 33% 27% 8% 1	1045
February	1st to 10th	Night	10% 10% 38% 29% 11% 3	950
	11th to 20th	Night	11% 9% 33% 31% 13% 3	887
	21st to end	Night	5% 10% 34% 33% 16% 2	628
March	1st to 10th	Night	10% 9% 28% 34% 16% 2	760
	11th to 20th	Night	16% 10% 35% 27% 10% 2	753
	21st to end	Night	12% 8% 30% 30% 18% 3	627
April	1st to 10th	Night	14% 9% 30% 32% 14% 2	570
	11th to 20th	Night	17% 6% 32% 30% 13% 1	563
	21st to end	Night	14% 9% 31% 34% 11% 1	570
May	1st to 10th	Night	19% 9% 30% 31% 10% 1	570
	11th to 20th	Night	16% 9% 29% 32% 13% 1	534
	21st to end	Night	19% 7% 28% 32% 13% 1	411
June	1st to 10th	Night	21% 6% 26% 31% 16% 1	380
	11th to 20th	Night	20% 8% 26% 31% 14% 1	380
	21st to end	Night	16% 5% 23% 36% 18% 2	380
July	1st to 10th	Night	14% 5% 21% 39% 19% 1	370
	11th to 20th	Night	13% 5% 21% 35% 23% 3	368
	21st to end	Night	15% 4 18% 35% 23% 4	438
August	1st to 10th	Night	12% 6% 23% 32% 23% 3	567
	11th to 20th	Night	13% 8% 23% 33% 21% 3	564
	21st to end	Night	17% 6% 26% 35% 15% 1	627
September	1st to 10th	Night	18% 8% 26% 32% 15% 1	570
	11th to 20th	Night	22% 6% 27% 35% 10%	570
	21st to end	Night	18% 10% 32% 33% 7% 1	575
October	1st to 10th	Night	25% 9% 31% 25% 9% 1	760
	11th to 20th	Night	26% 10% 30% 23% 8% 2	925
	21st to end	Night	26% 13% 29% 23% 9% 1	1045
November	1st to 10th	Night	24% 11% 32% 22% 10% 1	975
	11th to 20th	Night	20% 12% 34% 27% 7% 1	956
	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 2024-11-08 21:45:34. Version ac07

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