Piney Mountain
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Piney Mountain clear sky chart from 2005-11-06 to 2024-11-03.

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	15% 6% 2 6% 5% 4 5% 4 6% 8% 39%	101288
	Night	15% 7% 2 6% 4 4 4 4 5% 7% 41%	97631
Transparency	Day	42% 7% 13% 23% 14% 2	101089
	Night	42% 7% 12% 23% 14% 2	97500
Seeing	Day	19% 17% 27% 21% 12% 4	14876
	Night	18% 15% 29% 27% 11% 1	24307

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	15% 7% 3 8% 4 4 4 4 5% 6% 40%	2517
	11th to 20th	Day	13% 12% 5% 8% 6% 6% 5% 4 6% 6% 29%	2836
	21st to end	Day	16% 12% 4 8% 5% 5% 4 3 5% 6% 31%	3124
February	1st to 10th	Day	14% 9% 3 7% 5% 6% 6% 4 4 6% 36%	1710
	11th to 20th	Day	13% 9% 3 7% 5% 5% 6% 4 4 7% 36%	1689
	21st to end	Day	19% 8% 4 8% 4 4 4 4 4 6% 36%	1570
March	1st to 10th	Day	22% 7% 2 6% 4 4 5% 4 5% 7% 35%	3365
	11th to 20th	Day	9% 6% 2 7% 5% 5% 5% 4 5% 8% 43%	3480
	21st to end	Day	18% 9% 2 5% 3 4 4 3 4 6% 41%	3876
April	1st to 10th	Day	14% 8% 2 8% 6% 5% 4 4 5% 7% 37%	2280
	11th to 20th	Day	14% 8% 2 6% 5% 4 4 4 4 7% 42%	2254
	21st to end	Day	18% 8% 2 6% 4 4 4 4 6% 6% 39%	2282
May	1st to 10th	Day	28% 6% 2 6% 4 4 4 3 5% 7% 30%	4082
	11th to 20th	Day	24% 7% 3 7% 5% 4 5% 4 5% 7% 29%	4356
	21st to end	Day	11% 5% 2 6% 4 5% 5% 5% 6% 9% 42%	4823
June	1st to 10th	Day	13% 5% 2 6% 5% 4 5% 4 7% 10% 40%	2660
	11th to 20th	Day	12% 5% 2 7% 5% 4 5% 5% 7% 9% 38%	2660
	21st to end	Day	10% 4 2 5% 5% 4 5% 4 7% 11% 43%	2660
July	1st to 10th	Day	6% 4 2 6% 6% 5% 6% 5% 8% 9% 43%	4440
	11th to 20th	Day	8% 5% 2 5% 5% 5% 5% 5% 7% 10% 43%	4394
	21st to end	Day	11% 6% 3 7% 5% 5% 5% 4 6% 8% 39%	4466
August	1st to 10th	Day	18% 4 2 6% 5% 5% 6% 4 7% 9% 34%	4104
	11th to 20th	Day	13% 4 2 5% 4 4 6% 5% 7% 9% 41%	3921
	21st to end	Day	15% 4 1 5% 3 3 4 4 6% 8% 47%	4180
September	1st to 10th	Day	17% 5% 2 5% 3 4 4 3 6% 6% 45%	2280
	11th to 20th	Day	13% 5% 2 5% 3 4 4 4 6% 7% 47%	2280
	21st to end	Day	22% 6% 2 5% 4 3 4 3 5% 6% 39%	1994
October	1st to 10th	Day	16% 6% 2 5% 4 4 5% 3 5% 6% 45%	1900
	11th to 20th	Day	16% 5% 2 5% 4 3 4 3 5% 7% 45%	1900
	21st to end	Day	14% 7% 2 6% 4 4 4 4 4 7% 44%	2090
November	1st to 10th	Day	12% 6% 2 5% 3 3 4 3 5% 7% 50%	1752
	11th to 20th	Day	16% 6% 2 4 4 4 4 4 5% 7% 44%	1641
	21st to end	Day	16% 7% 2 5% 5% 4 4 4 5% 8% 41%	1520
December	1st to 10th	Day	17% 8% 3 7% 5% 5% 4 5% 6% 8% 33%	1520
	11th to 20th	Day	16% 7% 3 7% 5% 5% 5% 4 7% 8% 35%	1910
	21st to end	Day	18% 7% 3 9% 5% 5% 5% 5% 6% 7% 30%	2772
January	1st to 10th	Night	13% 8% 3 7% 6% 4 4 4 6% 8% 38%	4429
	11th to 20th	Night	16% 8% 3 7% 4 4 4 4 5% 6% 39%	4120
	21st to end	Night	19% 11% 4 7% 4 5% 4 3 5% 5% 33%	4532
February	1st to 10th	Night	16% 8% 2 7% 5% 4 5% 3 5% 6% 39%	2470
	11th to 20th	Night	15% 9% 3 7% 5% 4 4 3 5% 6% 38%	2375
	21st to end	Night	17% 9% 2 7% 5% 4 5% 4 5% 6% 37%	1884
March	1st to 10th	Night	20% 8% 2 6% 4 4 3 3 4 6% 38%	3484
	11th to 20th	Night	11% 5% 2 6% 5% 5% 4 3 5% 7% 47%	3480
	21st to end	Night	13% 9% 2 5% 4 4 3 3 4 5% 46%	3754
April	1st to 10th	Night	16% 8% 3 7% 6% 5% 5% 4 5% 7% 35%	1900
	11th to 20th	Night	14% 6% 2 7% 4 4 4 3 5% 9% 42%	1875
	21st to end	Night	19% 5% 2 5% 4 3 4 4 6% 7% 41%	1900
May	1st to 10th	Night	27% 8% 3 7% 4 4 3 3 5% 6% 31%	2827
	11th to 20th	Night	25% 9% 3 6% 4 3 4 4 5% 6% 30%	2537
	21st to end	Night	12% 6% 2 5% 5% 4 5% 5% 7% 10% 39%	2732
June	1st to 10th	Night	12% 6% 2 4 4 3 5% 4 6% 8% 47%	1520
	11th to 20th	Night	11% 5% 2 6% 5% 6% 5% 4 6% 10% 40%	1520
	21st to end	Night	10% 5% 2 6% 3 5% 4 4 7% 11% 44%	1520
July	1st to 10th	Night	7% 4 1 6% 5% 5% 6% 5% 7% 11% 43%	2520
	11th to 20th	Night	8% 5% 2 6% 5% 5% 5% 5% 7% 11% 43%	2548
	21st to end	Night	13% 6% 2 6% 5% 4 4 3 6% 8% 42%	3087
August	1st to 10th	Night	18% 4 2 7% 4 5% 4 4 6% 9% 37%	2825
	11th to 20th	Night	12% 6% 2 7% 5% 4 4 3 6% 8% 43%	2874
	21st to end	Night	16% 4 1 4 3 4 3 3 5% 8% 48%	3476
September	1st to 10th	Night	15% 4 2 6% 4 3 4 2 4 7% 48%	1900
	11th to 20th	Night	12% 5% 2 5% 3 3 4 2 5% 7% 53%	1900
	21st to end	Night	21% 6% 2 4 4 4 4 3 5% 6% 40%	2181
October	1st to 10th	Night	18% 7% 2 5% 3 3 3 3 4 6% 45%	2280
	11th to 20th	Night	14% 5% 2 5% 4 3 4 3 4 6% 49%	2280
	21st to end	Night	15% 6% 1 5% 3 4 4 3 6% 7% 46%	2508
November	1st to 10th	Night	10% 6% 2 6% 4 4 4 3 5% 6% 51%	2368
	11th to 20th	Night	14% 8% 2 5% 4 3 4 3 5% 7% 46%	2536
	21st to end	Night	14% 5% 2 5% 4 5% 4 4 6% 7% 44%	2660
December	1st to 10th	Night	16% 7% 3 7% 5% 5% 5% 4 5% 7% 36%	2660
	11th to 20th	Night	17% 6% 2 6% 4 4 5% 4 7% 7% 38%	3285
	21st to end	Night	16% 8% 3 7% 5% 5% 6% 5% 7% 8% 31%	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	44% 5% 14% 24% 9% 4	2518
	11th to 20th	Day	53% 6% 11% 16% 11% 3	2836
	21st to end	Day	54% 5% 10% 22% 7% 1	3124
February	1st to 10th	Day	49% 5% 13% 21% 10% 2	1710
	11th to 20th	Day	47% 6% 11% 23% 11% 2	1698
	21st to end	Day	49% 5% 11% 20% 11% 4	1570
March	1st to 10th	Day	48% 6% 11% 23% 10% 2	3365
	11th to 20th	Day	36% 6% 12% 27% 15% 3	3480
	21st to end	Day	45% 5% 10% 21% 15% 3	3876
April	1st to 10th	Day	45% 6% 13% 17% 15% 3	2280
	11th to 20th	Day	41% 6% 11% 21% 17% 3	2254
	21st to end	Day	44% 6% 10% 21% 16% 3	2282
May	1st to 10th	Day	52% 7% 10% 19% 11% 1	4120
	11th to 20th	Day	52% 9% 13% 17% 8% 1	4360
	21st to end	Day	35% 8% 15% 23% 17% 2	4837
June	1st to 10th	Day	38% 7% 14% 23% 16% 1	2660
	11th to 20th	Day	39% 9% 15% 22% 13% 2	2660
	21st to end	Day	33% 9% 15% 28% 15% 1	2660
July	1st to 10th	Day	34% 11% 14% 26% 12% 3	4370
	11th to 20th	Day	33% 10% 17% 26% 13% 1	4319
	21st to end	Day	41% 8% 11% 21% 17% 1	4324
August	1st to 10th	Day	45% 9% 15% 23% 8%	4091
	11th to 20th	Day	36% 9% 13% 27% 15% 1	3960
	21st to end	Day	34% 6% 13% 28% 17% 2	4180
September	1st to 10th	Day	39% 6% 12% 19% 21% 4	2280
	11th to 20th	Day	33% 6% 12% 25% 20% 3	2280
	21st to end	Day	46% 5% 10% 18% 19% 2	1994
October	1st to 10th	Day	40% 5% 12% 23% 17% 2	1900
	11th to 20th	Day	38% 6% 12% 24% 18% 2	1900
	21st to end	Day	39% 6% 10% 25% 17% 2	2090
November	1st to 10th	Day	32% 6% 14% 24% 19% 5%	1752
	11th to 20th	Day	39% 6% 12% 22% 18% 3	1641
	21st to end	Day	41% 6% 12% 29% 10% 2	1520
December	1st to 10th	Day	48% 8% 15% 19% 9% 1	1520
	11th to 20th	Day	47% 5% 13% 26% 7% 1	1906
	21st to end	Day	51% 9% 16% 16% 8%	2772
January	1st to 10th	Night	45% 7% 13% 24% 10% 2	4429
	11th to 20th	Night	46% 5% 15% 23% 10% 2	4120
	21st to end	Night	53% 5% 9% 23% 8% 2	4532
February	1st to 10th	Night	45% 6% 13% 23% 11% 1	2470
	11th to 20th	Night	46% 5% 12% 19% 17% 2	2377
	21st to end	Night	47% 5% 11% 19% 14% 4	1884
March	1st to 10th	Night	47% 6% 10% 26% 11% 1	3484
	11th to 20th	Night	36% 6% 11% 30% 14% 2	3480
	21st to end	Night	40% 5% 9% 21% 21% 4	3754
April	1st to 10th	Night	48% 6% 11% 17% 15% 3	1900
	11th to 20th	Night	39% 6% 11% 21% 18% 4	1875
	21st to end	Night	40% 6% 13% 21% 16% 4	1900
May	1st to 10th	Night	54% 6% 8% 18% 12% 3	2854
	11th to 20th	Night	52% 9% 13% 16% 10% 1	2538
	21st to end	Night	37% 9% 16% 25% 11% 3	2739
June	1st to 10th	Night	35% 8% 11% 26% 17% 3	1520
	11th to 20th	Night	38% 10% 13% 23% 16% 2	1520
	21st to end	Night	33% 9% 13% 26% 17% 2	1520
July	1st to 10th	Night	35% 9% 17% 19% 14% 5%	2480
	11th to 20th	Night	34% 10% 16% 23% 15% 1	2500
	21st to end	Night	39% 7% 15% 18% 19% 1	2988
August	1st to 10th	Night	43% 9% 17% 22% 8% 1	2814
	11th to 20th	Night	37% 7% 12% 26% 16% 1	2901
	21st to end	Night	34% 7% 12% 29% 16% 2	3476
September	1st to 10th	Night	37% 5% 13% 21% 21% 4	1900
	11th to 20th	Night	32% 5% 10% 28% 23% 3	1900
	21st to end	Night	44% 5% 10% 20% 18% 2	2181
October	1st to 10th	Night	41% 5% 12% 24% 16% 2	2280
	11th to 20th	Night	35% 6% 10% 28% 18% 3	2280
	21st to end	Night	38% 5% 10% 27% 18% 2	2508
November	1st to 10th	Night	33% 5% 12% 25% 20% 5%	2368
	11th to 20th	Night	38% 5% 10% 25% 18% 4	2536
	21st to end	Night	39% 6% 14% 25% 15% 2	2660
December	1st to 10th	Night	47% 7% 13% 22% 11%	2660
	11th to 20th	Night	42% 7% 14% 21% 14% 2	3288
	21st to end	Night	48% 9% 15% 19% 8%	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	26% 33% 27% 12% 2 1	180
	11th to 20th	Day	31% 28% 31% 9% 2	268
	21st to end	Day	22% 36% 30% 9% 3	297
February	1st to 10th	Day	27% 31% 31% 10% 1	270
	11th to 20th	Day	31% 33% 31% 3 1	296
	21st to end	Day	32% 24% 27% 15% 2	382
March	1st to 10th	Day	26% 26% 27% 18% 3	460
	11th to 20th	Day	25% 30% 27% 12% 4 1	460
	21st to end	Day	27% 23% 31% 14% 4 1	506
April	1st to 10th	Day	23% 26% 31% 13% 6% 1	460
	11th to 20th	Day	19% 24% 29% 15% 11% 2	452
	21st to end	Day	25% 20% 32% 15% 6% 2	460
May	1st to 10th	Day	28% 20% 26% 16% 7% 3	463
	11th to 20th	Day	22% 18% 27% 21% 10% 2	487
	21st to end	Day	16% 10% 27% 25% 17% 5%	529
June	1st to 10th	Day	15% 15% 30% 18% 17% 4	490
	11th to 20th	Day	16% 12% 29% 25% 14% 4	490
	21st to end	Day	11% 12% 31% 27% 16% 4	490
July	1st to 10th	Day	11% 5% 25% 30% 19% 9%	485
	11th to 20th	Day	5% 6% 27% 30% 23% 8%	484
	21st to end	Day	12% 7% 25% 32% 20% 5%	532
August	1st to 10th	Day	11% 5% 22% 32% 22% 8%	486
	11th to 20th	Day	13% 7% 23% 31% 18% 8%	479
	21st to end	Day	12% 6% 22% 32% 18% 10%	539
September	1st to 10th	Day	18% 9% 20% 24% 18% 10%	490
	11th to 20th	Day	14% 5% 19% 32% 21% 9%	490
	21st to end	Day	27% 13% 23% 20% 12% 4	490
October	1st to 10th	Day	20% 11% 25% 22% 17% 5%	490
	11th to 20th	Day	18% 21% 26% 22% 11% 2	490
	21st to end	Day	17% 18% 36% 19% 10% 1	539
November	1st to 10th	Day	18% 18% 27% 23% 12% 2	403
	11th to 20th	Day	22% 25% 26% 20% 7% 1	301
	21st to end	Day	22% 24% 34% 14% 6%	180
December	1st to 10th	Day	25% 29% 28% 13% 4 1	180
	11th to 20th	Day	26% 28% 28% 13% 4	180
	21st to end	Day	22% 27% 28% 18% 5% 1	198
January	1st to 10th	Night	17% 29% 33% 19% 2	760
	11th to 20th	Night	22% 21% 31% 23% 3	760
	21st to end	Night	18% 25% 36% 20% 2	836
February	1st to 10th	Night	20% 23% 31% 24% 2	760
	11th to 20th	Night	22% 29% 36% 13% 1	743
	21st to end	Night	24% 25% 33% 15% 2	628
March	1st to 10th	Night	20% 22% 36% 19% 4	760
	11th to 20th	Night	23% 23% 31% 18% 6%	760
	21st to end	Night	20% 19% 38% 17% 5%	836
April	1st to 10th	Night	21% 26% 31% 17% 5%	760
	11th to 20th	Night	18% 18% 32% 25% 7% 1	751
	21st to end	Night	22% 15% 31% 24% 8%	760
May	1st to 10th	Night	22% 11% 29% 27% 11% 1	584
	11th to 20th	Night	19% 9% 33% 29% 9%	403
	21st to end	Night	14% 8% 22% 39% 15% 1	411
June	1st to 10th	Night	13% 4 28% 35% 19% 1	380
	11th to 20th	Night	13% 7% 27% 36% 16% 1	380
	21st to end	Night	10% 4 27% 46% 13%	380
July	1st to 10th	Night	10% 4 23% 36% 25% 2	370
	11th to 20th	Night	6% 3 20% 45% 25% 2	383
	21st to end	Night	10% 3 20% 42% 24% 2	624
August	1st to 10th	Night	12% 2 14% 45% 25% 3	567
	11th to 20th	Night	12% 6% 15% 40% 24% 4	614
	21st to end	Night	14% 3 17% 37% 26% 3	836
September	1st to 10th	Night	16% 5% 21% 33% 22% 3	760
	11th to 20th	Night	13% 5% 18% 34% 26% 4	760
	21st to end	Night	24% 8% 21% 28% 19% 2	760
October	1st to 10th	Night	21% 9% 22% 27% 18% 3	760
	11th to 20th	Night	17% 14% 28% 30% 10% 1	760
	21st to end	Night	19% 15% 29% 27% 9%	836
November	1st to 10th	Night	13% 15% 33% 27% 10% 1	749
	11th to 20th	Night	18% 23% 29% 23% 7% 1	760
	21st to end	Night	17% 22% 31% 25% 5%	760
December	1st to 10th	Night	21% 20% 34% 19% 5% 1	760
	11th to 20th	Night	19% 20% 35% 23% 4	760
	21st to end	Night	18% 21% 34% 25% 3	836

Page generated at 2024-10-31 03:39:25. Version ac07

Copyright © 2024 Attilla Danko.