North Smoke Tower Site
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the North Smoke Tower Site clear sky chart from 2005-11-06 to 2024-10-20.

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	10% 6% 2 7% 5% 5% 5% 5% 7% 8% 38%	100828
	Night	11% 6% 2 6% 4 4 5% 4 6% 8% 42%	97813
Transparency	Day	40% 9% 15% 17% 13% 6%	100641
	Night	37% 9% 15% 18% 14% 7%	97670
Seeing	Day	12% 9% 23% 25% 21% 11%	15270
	Night	12% 7% 23% 32% 22% 4	25303

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	13% 7% 2 7% 4 3 3 3 4 7% 47%	2836
	11th to 20th	Day	15% 7% 3 6% 5% 4 4 3 5% 6% 41%	2840
	21st to end	Day	12% 7% 2 6% 4 4 4 4 6% 7% 45%	3197
February	1st to 10th	Day	16% 8% 3 6% 4 4 3 4 5% 6% 42%	1900
	11th to 20th	Day	14% 6% 2 6% 4 3 4 4 4 6% 47%	1848
	21st to end	Day	13% 7% 3 6% 4 4 4 3 4 6% 48%	1592
March	1st to 10th	Day	15% 8% 3 7% 5% 4 5% 3 6% 7% 37%	3435
	11th to 20th	Day	7% 4 2 5% 5% 4 5% 5% 6% 8% 49%	3480
	21st to end	Day	15% 4 2 5% 4 4 4 4 6% 7% 45%	3815
April	1st to 10th	Day	9% 5% 2 6% 6% 4 5% 4 5% 8% 46%	2090
	11th to 20th	Day	11% 5% 2 8% 6% 5% 5% 4 5% 7% 43%	2090
	21st to end	Day	6% 4 2 4 4 5% 5% 4 6% 7% 52%	2405
May	1st to 10th	Day	8% 4 1 5% 4 5% 5% 4 6% 8% 48%	4082
	11th to 20th	Day	11% 7% 3 8% 6% 6% 6% 4 6% 8% 35%	4081
	21st to end	Day	6% 4 2 5% 5% 5% 5% 4 7% 11% 46%	4476
June	1st to 10th	Day	11% 6% 2 8% 7% 7% 6% 6% 7% 10% 30%	2470
	11th to 20th	Day	6% 6% 2 7% 7% 7% 8% 6% 9% 10% 31%	2470
	21st to end	Day	9% 7% 2 9% 8% 7% 7% 6% 9% 9% 28%	2470
July	1st to 10th	Day	7% 7% 3 11% 8% 8% 9% 7% 10% 12% 19%	4120
	11th to 20th	Day	4 4 3 8% 7% 7% 7% 7% 10% 14% 30%	4120
	21st to end	Day	6% 6% 3 9% 7% 8% 8% 7% 9% 13% 25%	4466
August	1st to 10th	Day	14% 6% 2 8% 6% 7% 7% 7% 9% 10% 23%	4104
	11th to 20th	Day	7% 5% 2 6% 6% 6% 7% 6% 8% 11% 35%	3924
	21st to end	Day	10% 7% 3 9% 7% 7% 7% 6% 8% 11% 25%	3897
September	1st to 10th	Day	11% 8% 3 10% 8% 7% 7% 6% 8% 8% 24%	2090
	11th to 20th	Day	14% 9% 3 10% 7% 7% 7% 5% 7% 8% 24%	2090
	21st to end	Day	12% 6% 3 7% 7% 4 5% 4 6% 7% 38%	2090
October	1st to 10th	Day	13% 7% 2 7% 5% 5% 5% 4 5% 7% 40%	2090
	11th to 20th	Day	7% 5% 2 5% 3 4 5% 3 4 7% 56%	1895
	21st to end	Day	9% 4 1 7% 5% 4 4 4 6% 6% 49%	1980
November	1st to 10th	Day	11% 5% 2 5% 4 3 4 3 5% 7% 51%	1857
	11th to 20th	Day	9% 7% 2 5% 4 4 3 3 5% 6% 51%	1831
	21st to end	Day	12% 6% 3 5% 4 5% 4 3 5% 6% 47%	1710
December	1st to 10th	Day	10% 7% 2 7% 5% 3 5% 4 6% 7% 44%	1710
	11th to 20th	Day	16% 7% 2 6% 4 3 3 3 5% 5% 44%	2153
	21st to end	Day	16% 9% 3 7% 5% 4 4 3 3 5% 41%	3124
January	1st to 10th	Night	14% 9% 3 5% 4 3 4 4 5% 6% 44%	4109
	11th to 20th	Night	11% 8% 2 6% 5% 5% 5% 4 6% 8% 40%	4120
	21st to end	Night	15% 8% 3 6% 4 4 4 4 6% 7% 41%	4455
February	1st to 10th	Night	13% 7% 2 6% 4 3 4 3 4 7% 45%	2280
	11th to 20th	Night	14% 7% 2 6% 4 3 3 3 4 6% 48%	2218
	21st to end	Night	12% 6% 2 6% 4 3 4 3 4 6% 49%	1860
March	1st to 10th	Night	18% 11% 3 7% 4 4 3 3 5% 5% 36%	3418
	11th to 20th	Night	8% 4 2 5% 3 3 4 4 7% 10% 50%	3480
	21st to end	Night	14% 5% 2 4 4 4 4 3 5% 7% 48%	3817
April	1st to 10th	Night	10% 6% 2 4 4 4 4 4 6% 7% 49%	2090
	11th to 20th	Night	9% 6% 3 6% 4 4 3 3 5% 7% 51%	2039
	21st to end	Night	6% 5% 2 4 3 4 3 4 6% 7% 57%	1789
May	1st to 10th	Night	6% 4 2 4 5% 4 5% 4 6% 8% 51%	2813
	11th to 20th	Night	13% 5% 2 7% 4 4 5% 3 6% 9% 42%	2812
	21st to end	Night	5% 3 1 4 3 4 4 3 6% 10% 57%	3079
June	1st to 10th	Night	10% 6% 3 6% 5% 5% 6% 6% 9% 9% 35%	1710
	11th to 20th	Night	6% 4 2 6% 6% 6% 7% 7% 9% 12% 36%	1710
	21st to end	Night	7% 4 2 6% 6% 5% 7% 6% 8% 14% 35%	1710
July	1st to 10th	Night	9% 8% 3 12% 7% 6% 7% 6% 8% 10% 23%	2840
	11th to 20th	Night	5% 6% 3 8% 5% 6% 7% 6% 10% 15% 30%	2840
	21st to end	Night	7% 7% 3 9% 6% 6% 7% 6% 11% 12% 25%	3087
August	1st to 10th	Night	13% 5% 3 8% 5% 6% 8% 6% 9% 10% 28%	2825
	11th to 20th	Night	5% 4 2 5% 4 4 6% 6% 8% 13% 42%	2900
	21st to end	Night	9% 7% 2 8% 5% 6% 6% 5% 7% 12% 34%	3726
September	1st to 10th	Night	11% 7% 3 9% 6% 6% 6% 4 7% 11% 30%	2090
	11th to 20th	Night	13% 7% 3 9% 6% 6% 6% 5% 7% 8% 30%	2090
	21st to end	Night	8% 7% 3 7% 4 5% 4 4 6% 9% 43%	2090
October	1st to 10th	Night	12% 6% 2 7% 4 3 4 3 4 8% 45%	2090
	11th to 20th	Night	7% 5% 2 5% 4 3 3 3 4 6% 58%	2269
	21st to end	Night	7% 4 2 6% 5% 4 4 4 6% 7% 51%	2376
November	1st to 10th	Night	11% 4 1 4 3 3 4 4 7% 7% 52%	2221
	11th to 20th	Night	11% 7% 2 4 4 3 3 3 4 6% 52%	2346
	21st to end	Night	13% 7% 2 6% 4 4 3 4 5% 6% 47%	2470
December	1st to 10th	Night	13% 7% 2 6% 3 3 4 4 5% 8% 45%	2470
	11th to 20th	Night	16% 7% 2 5% 4 3 3 3 3 7% 47%	3042
	21st to end	Night	16% 8% 3 7% 5% 4 4 3 5% 5% 40%	4532

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	37% 4 7% 17% 22% 13%	2837
	11th to 20th	Day	43% 6% 7% 14% 15% 15%	2840
	21st to end	Day	37% 7% 10% 14% 20% 13%	3197
February	1st to 10th	Day	42% 5% 9% 14% 20% 10%	1900
	11th to 20th	Day	38% 4 7% 15% 22% 13%	1858
	21st to end	Day	38% 5% 9% 16% 18% 14%	1592
March	1st to 10th	Day	44% 8% 9% 18% 15% 7%	3435
	11th to 20th	Day	30% 7% 14% 16% 18% 15%	3480
	21st to end	Day	35% 6% 10% 23% 16% 10%	3815
April	1st to 10th	Day	35% 7% 10% 17% 18% 13%	2090
	11th to 20th	Day	40% 6% 9% 17% 18% 10%	2090
	21st to end	Day	29% 7% 11% 22% 22% 9%	2405
May	1st to 10th	Day	29% 10% 14% 24% 16% 6%	4120
	11th to 20th	Day	42% 9% 13% 21% 13% 2	4085
	21st to end	Day	27% 9% 19% 26% 17% 2	4489
June	1st to 10th	Day	46% 11% 17% 14% 10% 1	2470
	11th to 20th	Day	42% 13% 18% 20% 7%	2470
	21st to end	Day	47% 14% 19% 14% 5%	2470
July	1st to 10th	Day	51% 17% 23% 8% 1	4055
	11th to 20th	Day	38% 15% 35% 9% 2	4051
	21st to end	Day	44% 17% 27% 10% 2	4324
August	1st to 10th	Day	49% 14% 24% 11% 2	4091
	11th to 20th	Day	38% 13% 19% 20% 9%	3963
	21st to end	Day	48% 13% 17% 20% 2	3897
September	1st to 10th	Day	53% 13% 15% 11% 6% 2	2090
	11th to 20th	Day	53% 12% 14% 13% 6% 1	2090
	21st to end	Day	44% 8% 12% 17% 16% 4	2090
October	1st to 10th	Day	42% 7% 10% 15% 15% 11%	2090
	11th to 20th	Day	28% 5% 8% 20% 29% 9%	1895
	21st to end	Day	33% 6% 8% 16% 22% 15%	1980
November	1st to 10th	Day	34% 4 10% 19% 19% 14%	1857
	11th to 20th	Day	34% 5% 9% 17% 24% 12%	1831
	21st to end	Day	38% 5% 9% 18% 23% 8%	1710
December	1st to 10th	Day	38% 5% 12% 22% 16% 7%	1710
	11th to 20th	Day	40% 5% 9% 17% 20% 9%	2150
	21st to end	Day	47% 4 5% 17% 19% 7%	3124
January	1st to 10th	Night	40% 5% 7% 13% 20% 14%	4109
	11th to 20th	Night	41% 6% 8% 14% 21% 10%	4120
	21st to end	Night	41% 8% 10% 12% 18% 11%	4455
February	1st to 10th	Night	40% 5% 10% 15% 19% 12%	2280
	11th to 20th	Night	37% 5% 8% 17% 18% 14%	2219
	21st to end	Night	37% 5% 10% 18% 18% 13%	1860
March	1st to 10th	Night	50% 6% 11% 15% 11% 7%	3418
	11th to 20th	Night	28% 7% 16% 19% 18% 12%	3480
	21st to end	Night	35% 6% 11% 19% 19% 10%	3817
April	1st to 10th	Night	32% 7% 14% 17% 18% 11%	2090
	11th to 20th	Night	33% 5% 10% 23% 20% 9%	2039
	21st to end	Night	25% 7% 13% 26% 21% 8%	1789
May	1st to 10th	Night	26% 12% 17% 25% 15% 5%	2840
	11th to 20th	Night	36% 10% 18% 23% 11% 2	2813
	21st to end	Night	20% 9% 17% 32% 20% 2	3087
June	1st to 10th	Night	38% 13% 20% 19% 9%	1710
	11th to 20th	Night	35% 14% 24% 20% 7%	1710
	21st to end	Night	36% 15% 25% 18% 5% 1	1710
July	1st to 10th	Night	51% 15% 24% 9% 1 1	2795
	11th to 20th	Night	39% 18% 32% 9% 3	2786
	21st to end	Night	44% 17% 26% 11% 2	2988
August	1st to 10th	Night	46% 15% 28% 10% 2	2814
	11th to 20th	Night	28% 14% 25% 23% 9%	2927
	21st to end	Night	41% 11% 24% 20% 3	3726
September	1st to 10th	Night	46% 13% 20% 14% 6% 2	2090
	11th to 20th	Night	49% 14% 14% 16% 6% 1	2090
	21st to end	Night	36% 8% 18% 20% 13% 4	2090
October	1st to 10th	Night	37% 7% 13% 17% 15% 11%	2090
	11th to 20th	Night	27% 6% 8% 23% 27% 9%	2269
	21st to end	Night	31% 7% 11% 17% 20% 14%	2376
November	1st to 10th	Night	30% 6% 11% 21% 18% 14%	2221
	11th to 20th	Night	34% 5% 9% 17% 24% 12%	2346
	21st to end	Night	38% 5% 10% 19% 19% 9%	2470
December	1st to 10th	Night	36% 6% 14% 21% 16% 6%	2470
	11th to 20th	Night	38% 6% 9% 17% 22% 9%	3044
	21st to end	Night	44% 6% 10% 17% 18% 5%	4532

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	14% 20% 46% 15% 4	270
	11th to 20th	Day	13% 15% 42% 19% 8% 2	270
	21st to end	Day	21% 22% 41% 13% 3	297
February	1st to 10th	Day	23% 15% 37% 18% 6% 1	270
	11th to 20th	Day	20% 18% 42% 14% 5% 1	270
	21st to end	Day	14% 18% 39% 25% 4	247
March	1st to 10th	Day	14% 17% 32% 28% 9%	460
	11th to 20th	Day	14% 18% 33% 21% 11% 3	460
	21st to end	Day	15% 16% 34% 22% 11% 2	506
April	1st to 10th	Day	14% 15% 33% 22% 14% 2	460
	11th to 20th	Day	10% 14% 33% 25% 13% 4	452
	21st to end	Day	8% 11% 25% 32% 15% 8%	460
May	1st to 10th	Day	6% 10% 27% 28% 20% 8%	463
	11th to 20th	Day	7% 6% 24% 27% 24% 12%	487
	21st to end	Day	10% 3 14% 29% 29% 14%	529
June	1st to 10th	Day	12% 3 13% 31% 23% 17%	490
	11th to 20th	Day	7% 5% 14% 26% 28% 21%	490
	21st to end	Day	8% 3 8% 25% 33% 22%	490
July	1st to 10th	Day	8% 1 8% 22% 34% 27%	485
	11th to 20th	Day	7% 2 5% 19% 38% 29%	484
	21st to end	Day	8% 3 7% 25% 35% 22%	532
August	1st to 10th	Day	14% 3 9% 17% 33% 23%	486
	11th to 20th	Day	8% 3 4 19% 34% 32%	479
	21st to end	Day	11% 3 10% 24% 32% 21%	539
September	1st to 10th	Day	13% 3 10% 24% 27% 23%	490
	11th to 20th	Day	16% 4 12% 29% 28% 11%	490
	21st to end	Day	14% 3 11% 28% 31% 12%	490
October	1st to 10th	Day	14% 6% 27% 28% 18% 6%	490
	11th to 20th	Day	7% 6% 23% 35% 22% 7%	486
	21st to end	Day	9% 7% 28% 34% 19% 3	495
November	1st to 10th	Day	16% 6% 28% 28% 19% 4	455
	11th to 20th	Day	16% 13% 34% 25% 10% 2	391
	21st to end	Day	13% 17% 37% 24% 9% 1	270
December	1st to 10th	Day	13% 18% 31% 24% 10% 4	270
	11th to 20th	Day	20% 18% 33% 23% 6%	270
	21st to end	Day	17% 12% 34% 27% 7% 2	297
January	1st to 10th	Night	17% 14% 34% 29% 7%	760
	11th to 20th	Night	13% 12% 30% 34% 11% 1	760
	21st to end	Night	17% 16% 36% 26% 5%	836
February	1st to 10th	Night	17% 12% 31% 31% 9% 1	760
	11th to 20th	Night	17% 15% 31% 30% 7%	743
	21st to end	Night	15% 13% 34% 35% 4	628
March	1st to 10th	Night	12% 14% 31% 37% 7%	760
	11th to 20th	Night	13% 10% 35% 30% 12% 1	760
	21st to end	Night	11% 13% 34% 31% 11%	836
April	1st to 10th	Night	12% 11% 33% 33% 10%	760
	11th to 20th	Night	12% 11% 34% 32% 11%	751
	21st to end	Night	7% 7% 29% 40% 17% 1	649
May	1st to 10th	Night	5% 3 28% 46% 17% 1	570
	11th to 20th	Night	8% 4 22% 40% 24% 2	561
	21st to end	Night	7% 2 13% 40% 34% 3	617
June	1st to 10th	Night	11% 2 14% 38% 30% 5%	570
	11th to 20th	Night	6% 2 10% 34% 36% 12%	570
	21st to end	Night	8% 2 9% 27% 43% 11%	570
July	1st to 10th	Night	6% 2 7% 24% 43% 18%	555
	11th to 20th	Night	7% 1 4 21% 49% 18%	552
	21st to end	Night	5% 1 7% 28% 49% 10%	624
August	1st to 10th	Night	8% 1 5% 25% 48% 12%	567
	11th to 20th	Night	7% 1 5% 21% 49% 18%	564
	21st to end	Night	13% 2 9% 26% 36% 13%	773
September	1st to 10th	Night	13% 2 11% 27% 34% 12%	760
	11th to 20th	Night	14% 3 14% 30% 32% 6%	760
	21st to end	Night	13% 2 13% 35% 32% 6%	760
October	1st to 10th	Night	15% 2 22% 35% 23% 3	760
	11th to 20th	Night	8% 5% 24% 36% 25% 1	759
	21st to end	Night	8% 6% 26% 37% 21% 2	792
November	1st to 10th	Night	11% 6% 29% 37% 16% 1	740
	11th to 20th	Night	13% 9% 30% 32% 15% 1	760
	21st to end	Night	14% 8% 30% 33% 15%	760
December	1st to 10th	Night	16% 9% 26% 32% 16% 1	760
	11th to 20th	Night	15% 10% 28% 32% 14%	760
	21st to end	Night	17% 12% 26% 32% 12%	836

Page generated at 2024-10-17 13:09:43. Version ac07

Copyright © 2024 Attilla Danko.