Palmer Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Palmer Lake clear sky chart from 2005-11-06 to 2024-01-16.

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	12% 7% 3 5% 5% 3 5% 5% 5% 7% 42%	74754
	Night	12% 8% 3 5% 5% 3 4 4 5% 7% 45%	75070
Transparency	Day	40% 6% 11% 23% 16% 3	74467
	Night	39% 5% 11% 23% 18% 3	74878
Seeing	Day	18% 12% 29% 24% 13% 4	14420
	Night	18% 13% 31% 25% 11% 1	24363

By Month

Percentage Cloud Cover SE (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	11% 10% 4 8% 5% 3 5% 4 3 6% 41%	1526
	11th to 20th	Day	15% 9% 4 8% 5% 3 4 4 5% 6% 36%	1670
	21st to end	Day	11% 9% 5% 7% 5% 3 3 4 4 6% 42%	1782
February	1st to 10th	Day	14% 11% 5% 7% 5% 4 4 4 4 6% 36%	1620
	11th to 20th	Day	15% 8% 4 7% 4 3 5% 5% 6% 7% 37%	1721
	21st to end	Day	15% 11% 3 6% 5% 4 5% 4 4 6% 37%	1480
March	1st to 10th	Day	13% 9% 5% 6% 4 2 4 4 3 6% 44%	1867
	11th to 20th	Day	18% 11% 3 6% 5% 3 5% 4 4 6% 35%	1980
	21st to end	Day	18% 12% 4 7% 6% 4 5% 4 5% 6% 30%	2267
April	1st to 10th	Day	10% 5% 3 6% 5% 4 4 4 6% 8% 47%	2160
	11th to 20th	Day	18% 8% 3 5% 5% 3 4 4 4 7% 39%	2134
	21st to end	Day	19% 8% 4 7% 5% 3 4 4 4 7% 37%	2160
May	1st to 10th	Day	17% 7% 3 5% 5% 4 5% 5% 6% 8% 36%	2160
	11th to 20th	Day	17% 6% 2 5% 5% 2 4 4 6% 8% 41%	2433
	21st to end	Day	11% 6% 3 6% 8% 5% 6% 6% 7% 8% 36%	2725
June	1st to 10th	Day	9% 4 2 5% 6% 3 6% 6% 6% 9% 44%	2520
	11th to 20th	Day	6% 4 2 5% 5% 3 5% 6% 7% 9% 49%	2520
	21st to end	Day	5% 3 2 4 6% 4 6% 6% 7% 10% 48%	2520
July	1st to 10th	Day	11% 4 2 5% 5% 4 6% 5% 7% 11% 41%	2520
	11th to 20th	Day	4 3 2 5% 5% 4 6% 6% 7% 10% 50%	2494
	21st to end	Day	8% 6% 2 5% 5% 4 6% 6% 8% 10% 40%	2546
August	1st to 10th	Day	8% 4 2 5% 6% 3 7% 6% 8% 10% 41%	2327
	11th to 20th	Day	9% 6% 3 5% 6% 4 6% 6% 8% 9% 39%	2125
	21st to end	Day	9% 4 3 5% 5% 3 5% 5% 6% 9% 45%	2376
September	1st to 10th	Day	13% 5% 2 4 4 3 4 4 6% 8% 48%	2160
	11th to 20th	Day	10% 5% 2 4 5% 3 5% 4 6% 8% 48%	2157
	21st to end	Day	9% 4 2 5% 4 3 4 5% 4 7% 52%	1941
October	1st to 10th	Day	9% 5% 2 5% 3 2 4 5% 4 7% 54%	1800
	11th to 20th	Day	14% 6% 2 4 4 3 3 4 3 6% 52%	1800
	21st to end	Day	18% 8% 2 5% 4 2 3 3 4 5% 46%	1980
November	1st to 10th	Day	11% 5% 2 4 4 2 4 4 3 6% 55%	1708
	11th to 20th	Day	12% 8% 3 5% 4 3 4 4 4 7% 47%	1710
	21st to end	Day	15% 9% 3 5% 5% 3 4 4 4 5% 43%	1644
December	1st to 10th	Day	14% 10% 3 5% 4 3 5% 3 4 7% 41%	1520
	11th to 20th	Day	13% 11% 5% 7% 7% 2 4 4 4 5% 38%	1918
	21st to end	Day	14% 15% 6% 7% 6% 3 4 5% 4 6% 30%	2783
January	1st to 10th	Night	13% 9% 4 7% 6% 3 4 4 5% 6% 41%	2635
	11th to 20th	Night	15% 9% 5% 8% 6% 3 4 4 4 5% 37%	2418
	21st to end	Night	12% 9% 5% 7% 7% 3 4 4 5% 6% 38%	2574
February	1st to 10th	Night	17% 10% 4 9% 4 2 4 4 4 6% 36%	2340
	11th to 20th	Night	13% 8% 4 7% 5% 3 3 4 4 6% 43%	2124
	21st to end	Night	16% 10% 4 6% 5% 3 4 4 4 5% 39%	1776
March	1st to 10th	Night	15% 10% 3 6% 4 3 4 3 4 5% 43%	2106
	11th to 20th	Night	19% 9% 3 6% 5% 3 4 4 5% 4 38%	1980
	21st to end	Night	18% 11% 4 6% 5% 3 5% 5% 5% 5% 33%	2088
April	1st to 10th	Night	9% 6% 3 5% 4 3 4 4 5% 7% 50%	1800
	11th to 20th	Night	13% 8% 2 5% 5% 3 4 4 6% 7% 44%	1775
	21st to end	Night	18% 7% 3 5% 5% 2 4 4 4 6% 41%	1800
May	1st to 10th	Night	15% 6% 2 4 4 3 4 4 5% 7% 46%	1800
	11th to 20th	Night	16% 6% 2 5% 4 2 4 4 4 7% 45%	1455
	21st to end	Night	9% 7% 2 6% 7% 3 5% 6% 6% 10% 38%	1551
June	1st to 10th	Night	8% 4 2 4 4 3 6% 4 7% 11% 48%	1440
	11th to 20th	Night	6% 4 1 3 3 2 4 5% 6% 11% 56%	1440
	21st to end	Night	2 3 2 3 3 3 6% 4 6% 10% 58%	1440
July	1st to 10th	Night	8% 3 2 4 4 2 5% 5% 5% 10% 51%	1440
	11th to 20th	Night	5% 3 1 3 4 2 5% 4 6% 10% 57%	1462
	21st to end	Night	6% 4 2 5% 5% 3 5% 5% 6% 10% 50%	1772
August	1st to 10th	Night	7% 3 1 5% 4 4 3 6% 7% 10% 50%	1611
	11th to 20th	Night	6% 3 1 4 5% 3 5% 5% 6% 9% 53%	1776
	21st to end	Night	7% 4 2 5% 4 3 4 4 6% 8% 54%	1980
September	1st to 10th	Night	13% 5% 2 4 3 2 4 4 4 6% 53%	1800
	11th to 20th	Night	8% 4 2 4 4 2 4 5% 6% 7% 54%	1800
	21st to end	Night	9% 4 2 4 3 2 4 5% 5% 7% 56%	1999
October	1st to 10th	Night	7% 3 2 4 4 2 3 3 4 6% 62%	2160
	11th to 20th	Night	14% 4 2 4 4 2 3 3 5% 6% 52%	2160
	21st to end	Night	19% 7% 2 4 3 2 3 3 4 5% 48%	2376
November	1st to 10th	Night	11% 5% 2 4 4 2 3 3 4 5% 58%	2368
	11th to 20th	Night	14% 6% 2 4 4 3 4 4 4 7% 49%	2470
	21st to end	Night	16% 10% 3 5% 4 2 3 4 3 5% 45%	2531
December	1st to 10th	Night	15% 10% 4 5% 4 3 4 4 5% 7% 38%	2660
	11th to 20th	Night	15% 10% 4 7% 5% 3 4 4 4 5% 41%	3279
	21st to end	Night	13% 18% 6% 9% 7% 4 4 4 4 5% 26%	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	46% 4 10% 22% 15% 3	1527
	11th to 20th	Day	48% 5% 10% 25% 11% 1	1670
	21st to end	Day	43% 4 14% 24% 13% 3	1782
February	1st to 10th	Day	51% 4 10% 21% 13% 1	1620
	11th to 20th	Day	46% 6% 12% 19% 13% 4	1731
	21st to end	Day	48% 5% 7% 24% 11% 6%	1480
March	1st to 10th	Day	43% 5% 9% 22% 17% 5%	1867
	11th to 20th	Day	50% 6% 10% 17% 14% 3	1980
	21st to end	Day	56% 6% 10% 18% 9% 1	2267
April	1st to 10th	Day	35% 6% 13% 25% 20% 1	2160
	11th to 20th	Day	46% 5% 10% 19% 16% 3	2134
	21st to end	Day	48% 5% 10% 22% 13% 1	2160
May	1st to 10th	Day	46% 8% 12% 22% 11% 1	2160
	11th to 20th	Day	42% 6% 13% 23% 15% 2	2437
	21st to end	Day	44% 10% 14% 19% 12% 1	2725
June	1st to 10th	Day	35% 7% 14% 26% 16% 1	2520
	11th to 20th	Day	30% 8% 12% 27% 20% 3	2520
	21st to end	Day	28% 9% 18% 25% 16% 5%	2520
July	1st to 10th	Day	36% 8% 14% 24% 14% 4	2451
	11th to 20th	Day	28% 9% 14% 26% 18% 4	2419
	21st to end	Day	36% 10% 13% 28% 12% 1	2405
August	1st to 10th	Day	35% 10% 14% 25% 14%	2313
	11th to 20th	Day	39% 10% 12% 26% 12% 1	2125
	21st to end	Day	34% 7% 13% 24% 16% 6%	2376
September	1st to 10th	Day	34% 6% 11% 29% 16% 4	2160
	11th to 20th	Day	33% 6% 9% 25% 24% 2	2157
	21st to end	Day	31% 6% 7% 28% 25% 3	1941
October	1st to 10th	Day	31% 5% 8% 25% 26% 4	1800
	11th to 20th	Day	36% 4 8% 25% 23% 6%	1800
	21st to end	Day	41% 3 8% 25% 18% 5%	1980
November	1st to 10th	Day	33% 4 11% 25% 21% 6%	1708
	11th to 20th	Day	38% 4 8% 23% 20% 7%	1710
	21st to end	Day	44% 4 8% 25% 18% 1	1644
December	1st to 10th	Day	45% 4 10% 26% 13% 2	1520
	11th to 20th	Day	49% 5% 7% 18% 20% 1	1915
	21st to end	Day	56% 6% 10% 15% 12% 2	2783
January	1st to 10th	Night	45% 6% 9% 21% 17% 3	2635
	11th to 20th	Night	49% 4 10% 22% 13% 1	2418
	21st to end	Night	46% 4 11% 22% 14% 2	2574
February	1st to 10th	Night	50% 4 9% 21% 13% 2	2340
	11th to 20th	Night	44% 4 12% 20% 17% 3	2125
	21st to end	Night	49% 3 9% 22% 14% 4	1776
March	1st to 10th	Night	44% 4 9% 20% 17% 5%	2106
	11th to 20th	Night	50% 5% 9% 20% 14% 3	1980
	21st to end	Night	53% 6% 11% 20% 9% 1	2088
April	1st to 10th	Night	32% 6% 13% 28% 19% 3	1800
	11th to 20th	Night	40% 6% 10% 23% 17% 4	1775
	21st to end	Night	45% 5% 9% 24% 16% 1	1800
May	1st to 10th	Night	39% 7% 14% 23% 16% 2	1800
	11th to 20th	Night	39% 8% 12% 22% 17% 2	1456
	21st to end	Night	41% 9% 13% 19% 15% 3	1552
June	1st to 10th	Night	30% 8% 16% 26% 19% 2	1440
	11th to 20th	Night	22% 8% 13% 32% 21% 4	1440
	21st to end	Night	20% 9% 16% 29% 20% 6%	1440
July	1st to 10th	Night	29% 7% 17% 26% 16% 4	1400
	11th to 20th	Night	23% 7% 16% 29% 21% 4	1414
	21st to end	Night	29% 8% 14% 31% 17% 1	1673
August	1st to 10th	Night	26% 10% 17% 31% 15% 2	1601
	11th to 20th	Night	26% 8% 15% 28% 20% 2	1776
	21st to end	Night	28% 7% 13% 27% 20% 5%	1980
September	1st to 10th	Night	33% 5% 9% 28% 19% 6%	1800
	11th to 20th	Night	29% 6% 11% 26% 27% 2	1800
	21st to end	Night	28% 7% 8% 24% 29% 4	1999
October	1st to 10th	Night	24% 4 11% 28% 28% 4	2160
	11th to 20th	Night	33% 4 9% 26% 22% 6%	2160
	21st to end	Night	40% 4 9% 21% 21% 5%	2376
November	1st to 10th	Night	30% 4 12% 27% 22% 6%	2368
	11th to 20th	Night	37% 4 8% 23% 23% 6%	2470
	21st to end	Night	43% 3 8% 23% 20% 2	2531
December	1st to 10th	Night	45% 5% 11% 22% 16% 2	2660
	11th to 20th	Night	46% 4 9% 23% 17% 1	3281
	21st to end	Night	59% 6% 10% 15% 9% 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	29% 22% 36% 11% 2	270
	11th to 20th	Day	33% 21% 37% 8%	257
	21st to end	Day	24% 31% 35% 9% 1	264
February	1st to 10th	Day	31% 23% 34% 11% 1	240
	11th to 20th	Day	36% 23% 33% 6% 1 1	240
	21st to end	Day	34% 25% 32% 9% 1 1	198
March	1st to 10th	Day	25% 27% 38% 9% 1	240
	11th to 20th	Day	35% 18% 33% 11% 2 1	240
	21st to end	Day	35% 20% 34% 10% 1	353
April	1st to 10th	Day	20% 20% 38% 17% 5%	420
	11th to 20th	Day	28% 19% 30% 17% 5% 1	412
	21st to end	Day	26% 19% 34% 15% 5% 1	420
May	1st to 10th	Day	24% 16% 36% 17% 5% 1	423
	11th to 20th	Day	20% 14% 30% 25% 9% 2	597
	21st to end	Day	12% 10% 35% 25% 13% 5%	679
June	1st to 10th	Day	13% 5% 26% 30% 23% 4	630
	11th to 20th	Day	8% 4 28% 39% 17% 4	630
	21st to end	Day	6% 7% 31% 34% 17% 4	630
July	1st to 10th	Day	13% 2 18% 29% 29% 9%	621
	11th to 20th	Day	5% 4 23% 39% 25% 5%	618
	21st to end	Day	9% 4 19% 35% 27% 6%	684
August	1st to 10th	Day	11% 2 16% 40% 24% 6%	625
	11th to 20th	Day	15% 3 18% 32% 24% 8%	439
	21st to end	Day	11% 3 16% 32% 28% 11%	495
September	1st to 10th	Day	13% 4 18% 34% 24% 6%	450
	11th to 20th	Day	9% 3 22% 33% 22% 11%	450
	21st to end	Day	12% 8% 27% 30% 17% 7%	411
October	1st to 10th	Day	15% 11% 33% 29% 10% 2	270
	11th to 20th	Day	23% 16% 39% 19% 3	270
	21st to end	Day	35% 19% 30% 13% 2	297
November	1st to 10th	Day	15% 16% 41% 19% 7% 2	270
	11th to 20th	Day	26% 20% 32% 17% 5% 1	270
	21st to end	Day	31% 14% 36% 15% 4	270
December	1st to 10th	Day	23% 24% 31% 14% 5% 2	270
	11th to 20th	Day	31% 18% 33% 14% 3	270
	21st to end	Day	32% 23% 32% 10% 2	297
January	1st to 10th	Night	24% 24% 33% 15% 3	950
	11th to 20th	Night	25% 24% 34% 13% 3	930
	21st to end	Night	20% 24% 38% 16% 1	990
February	1st to 10th	Night	26% 22% 36% 14% 2	900
	11th to 20th	Night	24% 21% 40% 14% 2	729
	21st to end	Night	27% 20% 36% 16% 1	592
March	1st to 10th	Night	26% 18% 36% 17% 2	666
	11th to 20th	Night	25% 15% 37% 19% 4	540
	21st to end	Night	27% 15% 34% 20% 3	594
April	1st to 10th	Night	16% 20% 39% 22% 4	540
	11th to 20th	Night	21% 15% 32% 26% 5% 1	533
	21st to end	Night	23% 13% 39% 20% 5%	540
May	1st to 10th	Night	20% 10% 34% 28% 9%	540
	11th to 20th	Night	20% 7% 33% 26% 12% 1	531
	21st to end	Night	13% 7% 28% 33% 15% 3	584
June	1st to 10th	Night	10% 4 21% 38% 25% 2	540
	11th to 20th	Night	9% 1 27% 39% 21% 2	540
	21st to end	Night	3 3 30% 40% 22% 1	540
July	1st to 10th	Night	11% 2 13% 36% 31% 8%	525
	11th to 20th	Night	7% 3 15% 43% 28% 4	522
	21st to end	Night	8% 2 15% 45% 27% 3	591
August	1st to 10th	Night	8% 2 15% 39% 33% 4	537
	11th to 20th	Night	8% 2 16% 39% 32% 3	534
	21st to end	Night	7% 2 15% 35% 35% 6%	594
September	1st to 10th	Night	13% 2 15% 38% 27% 4	540
	11th to 20th	Night	9% 3 16% 38% 28% 6%	540
	21st to end	Night	11% 8% 25% 27% 25% 5%	703
October	1st to 10th	Night	9% 5% 30% 32% 20% 4	720
	11th to 20th	Night	18% 14% 34% 26% 8% 1	720
	21st to end	Night	25% 14% 34% 21% 6%	792
November	1st to 10th	Night	14% 11% 42% 25% 8% 1	740
	11th to 20th	Night	20% 17% 32% 24% 6% 1	760
	21st to end	Night	23% 19% 34% 19% 4	821
December	1st to 10th	Night	25% 16% 37% 18% 4	950
	11th to 20th	Night	26% 15% 36% 19% 3	950
	21st to end	Night	26% 23% 34% 16% 2	1045

Page generated at 2024-01-13 18:28:34. Version ac07

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