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 2024-12-09.

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 6% 4 4 4 4 5% 7% 43%	101421
	Night	13% 8% 3 6% 4 4 4 3 5% 6% 44%	98410
Transparency	Day	38% 5% 11% 25% 17% 3	105056
	Night	38% 5% 11% 24% 18% 4	102916
Seeing	Day	18% 12% 29% 24% 13% 4	15677
	Night	18% 13% 31% 25% 11% 1	25516

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% 12% 5% 10% 4 3 4 3 4 6% 38%	2536
	11th to 20th	Day	13% 9% 4 8% 4 4 4 3 4 5% 42%	2850
	21st to end	Day	20% 10% 5% 7% 3 3 3 3 3 6% 36%	3135
February	1st to 10th	Day	14% 12% 4 8% 5% 4 4 3 5% 6% 36%	1710
	11th to 20th	Day	15% 9% 3 7% 4 4 4 4 6% 6% 38%	1819
	21st to end	Day	14% 11% 3 6% 4 5% 4 4 5% 6% 38%	1570
March	1st to 10th	Day	18% 12% 3 6% 3 3 3 3 3 4 41%	3243
	11th to 20th	Day	13% 8% 2 4 3 3 4 3 4 6% 50%	3480
	21st to end	Day	13% 9% 3 6% 5% 5% 4 4 5% 7% 37%	3972
April	1st to 10th	Day	10% 5% 3 6% 5% 5% 4 3 6% 8% 46%	2280
	11th to 20th	Day	16% 8% 3 6% 4 4 4 3 5% 7% 40%	2254
	21st to end	Day	18% 8% 3 7% 5% 4 4 4 4 6% 37%	2280
May	1st to 10th	Day	13% 7% 3 7% 5% 6% 6% 5% 7% 9% 32%	3765
	11th to 20th	Day	17% 8% 2 6% 4 4 4 3 5% 8% 38%	4325
	21st to end	Day	11% 7% 3 7% 5% 5% 5% 3 5% 7% 42%	4824
June	1st to 10th	Day	10% 5% 2 6% 5% 5% 5% 5% 6% 9% 43%	2660
	11th to 20th	Day	6% 4 2 5% 5% 4 5% 5% 7% 9% 49%	2660
	21st to end	Day	5% 4 2 4 5% 6% 5% 5% 7% 10% 48%	2660
July	1st to 10th	Day	13% 4 2 6% 5% 5% 5% 4 7% 9% 40%	4440
	11th to 20th	Day	4 4 2 6% 4 5% 5% 5% 6% 10% 49%	4386
	21st to end	Day	8% 6% 2 7% 6% 6% 7% 6% 8% 10% 34%	4465
August	1st to 10th	Day	6% 3 2 4 4 3 5% 4 7% 10% 51%	4089
	11th to 20th	Day	11% 6% 2 6% 4 5% 5% 4 6% 8% 44%	3729
	21st to end	Day	8% 4 2 5% 3 4 4 4 6% 9% 51%	4180
September	1st to 10th	Day	12% 5% 2 4 4 4 5% 2 6% 8% 49%	2280
	11th to 20th	Day	10% 6% 2 5% 4 4 4 3 6% 7% 47%	2276
	21st to end	Day	10% 5% 2 6% 4 4 4 4 5% 7% 51%	2048
October	1st to 10th	Day	9% 5% 2 5% 2 3 3 3 4 7% 56%	1900
	11th to 20th	Day	14% 6% 2 4 3 3 3 3 3 5% 54%	1900
	21st to end	Day	17% 8% 2 6% 3 3 2 2 4 5% 47%	2090
November	1st to 10th	Day	12% 6% 2 5% 3 3 4 3 3 5% 54%	1800
	11th to 20th	Day	12% 9% 3 6% 3 4 3 3 4 6% 47%	1800
	21st to end	Day	14% 10% 3 5% 4 3 3 3 5% 5% 43%	1730
December	1st to 10th	Day	13% 11% 3 6% 4 4 5% 2 5% 6% 42%	1584
	11th to 20th	Day	13% 11% 5% 8% 5% 3 4 3 4 5% 38%	1918
	21st to end	Day	14% 15% 6% 8% 5% 4 4 4 4 6% 30%	2783
January	1st to 10th	Night	13% 10% 5% 10% 5% 4 4 3 4 5% 36%	4415
	11th to 20th	Night	12% 9% 4 12% 6% 5% 6% 4 4 5% 33%	4120
	21st to end	Night	22% 14% 5% 7% 4 3 3 2 4 4 32%	4532
February	1st to 10th	Night	16% 11% 4 9% 4 3 4 3 5% 5% 36%	2470
	11th to 20th	Night	12% 9% 4 8% 4 3 3 3 4 5% 43%	2246
	21st to end	Night	15% 10% 4 7% 4 4 4 3 5% 4 39%	1884
March	1st to 10th	Night	19% 12% 2 6% 3 3 3 2 4 4 43%	3637
	11th to 20th	Night	14% 8% 2 5% 3 3 4 3 5% 5% 49%	3480
	21st to end	Night	14% 10% 3 7% 5% 5% 4 4 6% 6% 35%	3658
April	1st to 10th	Night	10% 7% 2 5% 4 3 4 4 5% 7% 50%	1900
	11th to 20th	Night	13% 8% 2 6% 4 3 4 3 6% 7% 44%	1875
	21st to end	Night	18% 8% 3 6% 5% 3 4 2 4 6% 41%	1900
May	1st to 10th	Night	17% 7% 2 5% 3 4 3 3 6% 7% 42%	3130
	11th to 20th	Night	16% 8% 2 5% 3 3 4 3 4 8% 44%	2558
	21st to end	Night	11% 8% 2 7% 5% 5% 5% 4 6% 8% 38%	2743
June	1st to 10th	Night	9% 4 2 5% 3 5% 5% 3 7% 9% 47%	1520
	11th to 20th	Night	6% 4 1 4 3 3 4 3 6% 11% 56%	1520
	21st to end	Night	2 3 1 4 3 5% 5% 3 6% 10% 57%	1520
July	1st to 10th	Night	12% 4 2 4 4 3 4 3 6% 9% 48%	2530
	11th to 20th	Night	5% 3 1 3 3 3 4 3 5% 9% 60%	2580
	21st to end	Night	6% 6% 2 8% 6% 5% 5% 4 7% 9% 41%	3098
August	1st to 10th	Night	5% 3 1 4 3 3 4 4 6% 9% 58%	2836
	11th to 20th	Night	9% 5% 1 6% 4 4 4 4 6% 9% 48%	3100
	21st to end	Night	6% 4 2 4 4 3 4 3 6% 9% 57%	3476
September	1st to 10th	Night	12% 6% 2 5% 3 3 4 3 4 5% 53%	1900
	11th to 20th	Night	8% 5% 2 5% 3 4 4 4 6% 7% 53%	1900
	21st to end	Night	9% 5% 2 5% 3 3 4 4 5% 7% 54%	2111
October	1st to 10th	Night	7% 3 1 4 3 3 3 2 4 6% 64%	2280
	11th to 20th	Night	13% 5% 2 4 3 3 3 2 5% 5% 54%	2280
	21st to end	Night	18% 7% 2 4 3 3 3 3 4 5% 48%	2508
November	1st to 10th	Night	11% 5% 2 4 3 3 3 2 4 5% 57%	2496
	11th to 20th	Night	14% 7% 2 4 3 4 3 3 5% 7% 49%	2600
	21st to end	Night	15% 10% 3 6% 3 2 3 3 4 6% 45%	2665
December	1st to 10th	Night	15% 10% 3 6% 3 5% 3 3 5% 7% 39%	2779
	11th to 20th	Night	15% 11% 4 7% 5% 4 4 2 4 5% 41%	3279
	21st to end	Night	13% 18% 6% 10% 6% 5% 4 4 5% 5% 25%	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	48% 3 9% 26% 12% 2	2537
	11th to 20th	Day	44% 4 8% 25% 16% 2	2850
	21st to end	Day	51% 4 10% 16% 15% 5%	3135
February	1st to 10th	Day	50% 4 10% 22% 13% 2	1710
	11th to 20th	Day	45% 6% 11% 19% 15% 5%	1829
	21st to end	Day	46% 5% 7% 23% 13% 6%	1570
March	1st to 10th	Day	48% 4 6% 21% 13% 8%	3243
	11th to 20th	Day	35% 5% 10% 27% 16% 7%	3480
	21st to end	Day	44% 7% 16% 21% 12% 1	3972
April	1st to 10th	Day	36% 5% 12% 25% 20% 2	2280
	11th to 20th	Day	44% 5% 11% 20% 16% 4	2254
	21st to end	Day	48% 5% 10% 21% 13% 1	2280
May	1st to 10th	Day	45% 9% 13% 21% 12% 1	3800
	11th to 20th	Day	45% 7% 11% 24% 12% 1	4329
	21st to end	Day	41% 7% 10% 22% 20% 1	4837
June	1st to 10th	Day	36% 7% 14% 26% 16% 2	2660
	11th to 20th	Day	30% 8% 12% 27% 21% 3	2660
	21st to end	Day	28% 9% 18% 25% 16% 5%	2660
July	1st to 10th	Day	40% 6% 12% 29% 12% 2	4371
	11th to 20th	Day	29% 6% 13% 34% 16% 2	4311
	21st to end	Day	41% 6% 16% 27% 8% 1	4325
August	1st to 10th	Day	27% 6% 16% 32% 19%	4075
	11th to 20th	Day	38% 6% 12% 25% 17% 2	3765
	21st to end	Day	30% 4 14% 36% 13% 3	4179
September	1st to 10th	Day	33% 6% 11% 28% 18% 5%	2280
	11th to 20th	Day	35% 6% 9% 25% 24% 2	2276
	21st to end	Day	32% 6% 7% 27% 24% 3	2048
October	1st to 10th	Day	18% 3 5% 19% 45% 10%	3160
	11th to 20th	Day	24% 2 6% 22% 37% 10%	3140
	21st to end	Day	31% 2 6% 31% 26% 4	3428
November	1st to 10th	Day	34% 4 10% 24% 22% 6%	1800
	11th to 20th	Day	38% 4 8% 22% 20% 7%	1800
	21st to end	Day	44% 4 8% 25% 17% 1	1730
December	1st to 10th	Day	44% 3 10% 27% 13% 2	1584
	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	50% 5% 9% 22% 13% 2	4415
	11th to 20th	Night	51% 4 10% 21% 12% 2	4120
	21st to end	Night	56% 4 8% 20% 10% 1	4532
February	1st to 10th	Night	50% 4 10% 20% 14% 2	2470
	11th to 20th	Night	43% 4 12% 20% 17% 3	2247
	21st to end	Night	48% 3 9% 21% 15% 4	1884
March	1st to 10th	Night	46% 4 8% 22% 15% 4	3637
	11th to 20th	Night	37% 5% 12% 24% 19% 5%	3480
	21st to end	Night	47% 7% 14% 25% 8% 1	3658
April	1st to 10th	Night	33% 5% 13% 27% 19% 3	1900
	11th to 20th	Night	40% 6% 9% 23% 18% 4	1875
	21st to end	Night	45% 5% 9% 24% 16% 1	1900
May	1st to 10th	Night	41% 8% 17% 20% 13% 2	3160
	11th to 20th	Night	39% 7% 13% 24% 15% 1	2559
	21st to end	Night	41% 9% 11% 23% 15% 1	2751
June	1st to 10th	Night	30% 8% 16% 25% 19% 2	1520
	11th to 20th	Night	22% 7% 12% 32% 22% 4	1520
	21st to end	Night	21% 8% 17% 29% 19% 7%	1520
July	1st to 10th	Night	34% 5% 15% 28% 15% 3	2490
	11th to 20th	Night	23% 5% 11% 39% 20% 2	2532
	21st to end	Night	39% 5% 18% 25% 12% 2	2999
August	1st to 10th	Night	22% 6% 18% 31% 22% 1	2826
	11th to 20th	Night	33% 5% 17% 24% 17% 3	3130
	21st to end	Night	25% 4 15% 37% 16% 3	3476
September	1st to 10th	Night	33% 5% 9% 27% 20% 6%	1900
	11th to 20th	Night	30% 6% 10% 26% 26% 2	1900
	21st to end	Night	30% 7% 8% 24% 27% 4	2111
October	1st to 10th	Night	14% 2 6% 16% 49% 12%	3800
	11th to 20th	Night	23% 2 7% 21% 32% 15%	3779
	21st to end	Night	31% 2 8% 26% 27% 6%	4120
November	1st to 10th	Night	31% 4 11% 26% 22% 5%	2496
	11th to 20th	Night	37% 4 7% 23% 24% 6%	2600
	21st to end	Night	43% 3 8% 24% 20% 2	2665
December	1st to 10th	Night	45% 4 10% 23% 16% 2	2779
	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	35% 21% 36% 8%	270
	21st to end	Day	26% 29% 34% 11% 1	297
February	1st to 10th	Day	30% 23% 33% 13% 1	270
	11th to 20th	Day	34% 23% 34% 7% 1 1	270
	21st to end	Day	34% 24% 32% 8%	225
March	1st to 10th	Day	26% 25% 39% 9% 1	270
	11th to 20th	Day	33% 20% 35% 10% 1 1	270
	21st to end	Day	34% 20% 34% 10% 2	391
April	1st to 10th	Day	22% 20% 37% 16% 5%	460
	11th to 20th	Day	28% 21% 29% 16% 5% 1	452
	21st to end	Day	27% 19% 34% 14% 5% 1	460
May	1st to 10th	Day	24% 17% 37% 17% 5% 1	463
	11th to 20th	Day	20% 13% 30% 24% 10% 2	646
	21st to end	Day	12% 11% 36% 24% 12% 4	734
June	1st to 10th	Day	13% 5% 27% 29% 22% 4	680
	11th to 20th	Day	8% 4 28% 40% 17% 4	680
	21st to end	Day	6% 7% 33% 34% 16% 4	680
July	1st to 10th	Day	14% 3 20% 28% 27% 9%	671
	11th to 20th	Day	5% 4 23% 39% 24% 5%	668
	21st to end	Day	10% 4 19% 35% 26% 6%	739
August	1st to 10th	Day	11% 2 18% 39% 23% 6%	674
	11th to 20th	Day	15% 3 21% 30% 23% 8%	479
	21st to end	Day	11% 3 16% 32% 27% 11%	539
September	1st to 10th	Day	12% 5% 18% 35% 24% 6%	490
	11th to 20th	Day	10% 4 22% 32% 21% 11%	490
	21st to end	Day	13% 8% 28% 29% 16% 6%	448
October	1st to 10th	Day	13% 11% 31% 30% 12% 3	300
	11th to 20th	Day	22% 15% 37% 22% 4 1	300
	21st to end	Day	33% 18% 33% 13% 2	330
November	1st to 10th	Day	17% 15% 42% 18% 6% 2	300
	11th to 20th	Day	25% 21% 32% 16% 5% 1	300
	21st to end	Day	32% 15% 34% 15% 4	300
December	1st to 10th	Day	23% 23% 33% 14% 5% 2	294
	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% 25% 33% 13% 3	950
	21st to end	Night	21% 24% 38% 16% 1	1045
February	1st to 10th	Night	26% 21% 36% 15% 2	950
	11th to 20th	Night	23% 21% 40% 14% 2	771
	21st to end	Night	26% 21% 36% 15% 1	628
March	1st to 10th	Night	26% 19% 36% 17% 2	703
	11th to 20th	Night	24% 16% 37% 19% 4	570
	21st to end	Night	27% 17% 34% 19% 3	627
April	1st to 10th	Night	17% 20% 38% 22% 4	570
	11th to 20th	Night	22% 15% 31% 26% 5% 1	563
	21st to end	Night	23% 14% 39% 20% 5%	570
May	1st to 10th	Night	20% 10% 35% 26% 9%	570
	11th to 20th	Night	20% 7% 34% 27% 12% 1	561
	21st to end	Night	13% 8% 29% 33% 14% 3	617
June	1st to 10th	Night	11% 4 22% 37% 24% 2	570
	11th to 20th	Night	9% 2 27% 39% 22% 2	570
	21st to end	Night	3 3 31% 40% 22% 1	570
July	1st to 10th	Night	11% 2 14% 36% 30% 8%	555
	11th to 20th	Night	7% 3 16% 43% 28% 4	552
	21st to end	Night	8% 2 16% 44% 27% 3	624
August	1st to 10th	Night	8% 2 15% 40% 32% 3	567
	11th to 20th	Night	8% 3 17% 39% 31% 3	564
	21st to end	Night	7% 2 15% 36% 34% 5%	627
September	1st to 10th	Night	13% 2 15% 38% 27% 4	570
	11th to 20th	Night	10% 4 16% 38% 28% 5%	570
	21st to end	Night	11% 8% 26% 27% 24% 4	743
October	1st to 10th	Night	9% 5% 29% 34% 20% 4	760
	11th to 20th	Night	17% 14% 33% 26% 9% 1	760
	21st to end	Night	24% 14% 35% 21% 6%	836
November	1st to 10th	Night	14% 11% 42% 25% 7% 1	780
	11th to 20th	Night	20% 17% 32% 25% 5% 1	800
	21st to end	Night	24% 20% 33% 19% 4	865
December	1st to 10th	Night	25% 16% 37% 18% 4	993
	11th to 20th	Night	26% 15% 36% 19% 3	950
	21st to end	Night	26% 23% 34% 16% 2	1045

Page generated at 2024-12-06 02:54:46. Version ac07

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