Conconully
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Conconully clear sky chart from 2005-11-06 to 2025-11-18.

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	7% 8% 3 7% 5% 5% 5% 4 6% 7% 44%	130827
	Night	7% 9% 3 7% 4 4 5% 4 6% 7% 45%	128203
Transparency	Day	34% 7% 14% 24% 16% 5%	130554
	Night	38% 8% 14% 23% 13% 4	128053
Seeing	Day	12% 16% 32% 25% 11% 2	15743
	Night	12% 7% 28% 35% 17% 2	24711

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	9% 15% 6% 15% 6% 4 5% 4 6% 7% 24%	3639
	11th to 20th	Day	7% 11% 3 8% 4 3 2 2 4 8% 48%	3616
	21st to end	Day	11% 17% 5% 9% 3 3 3 3 5% 6% 36%	4004
February	1st to 10th	Day	7% 13% 4 13% 5% 6% 5% 5% 5% 7% 30%	1690
	11th to 20th	Day	7% 14% 5% 9% 5% 4 5% 4 6% 7% 35%	1755
	21st to end	Day	6% 13% 5% 11% 6% 5% 4 5% 7% 9% 28%	1646
March	1st to 10th	Day	5% 11% 4 8% 5% 6% 6% 4 7% 8% 36%	4518
	11th to 20th	Day	4 10% 4 8% 5% 5% 5% 4 7% 7% 41%	4795
	21st to end	Day	8% 13% 5% 10% 6% 6% 6% 4 7% 8% 27%	5895
April	1st to 10th	Day	9% 12% 4 9% 7% 6% 6% 5% 6% 8% 28%	2400
	11th to 20th	Day	7% 12% 4 8% 6% 5% 5% 5% 7% 8% 33%	2372
	21st to end	Day	7% 12% 3 9% 6% 6% 5% 4 6% 8% 33%	2694
May	1st to 10th	Day	7% 8% 3 7% 4 5% 5% 4 6% 6% 45%	6320
	11th to 20th	Day	8% 10% 4 10% 7% 6% 6% 5% 6% 7% 32%	6277
	21st to end	Day	10% 8% 3 9% 6% 6% 6% 4 5% 8% 36%	6903
June	1st to 10th	Day	14% 8% 3 6% 5% 5% 6% 5% 5% 7% 34%	2800
	11th to 20th	Day	11% 8% 3 8% 6% 7% 7% 5% 6% 7% 33%	2800
	21st to end	Day	7% 6% 2 7% 5% 4 5% 4 6% 7% 47%	2998
July	1st to 10th	Day	2 2 1 3 2 3 3 3 5% 6% 69%	6371
	11th to 20th	Day	2 2 1 3 2 3 3 2 3 5% 73%	6320
	21st to end	Day	2 2 1 4 3 3 4 3 5% 7% 64%	6874
August	1st to 10th	Day	2 2 1 3 3 3 4 4 6% 8% 64%	4541
	11th to 20th	Day	2 3 1 4 3 5% 5% 4 6% 8% 58%	4374
	21st to end	Day	4 5% 2 7% 5% 4 5% 3 4 6% 54%	4322
September	1st to 10th	Day	6% 4 2 5% 4 3 4 3 5% 6% 60%	2400
	11th to 20th	Day	7% 6% 2 6% 5% 5% 5% 3 5% 7% 50%	2382
	21st to end	Day	8% 5% 2 6% 4 4 5% 3 4 5% 52%	2180
October	1st to 10th	Day	5% 4 2 5% 3 5% 5% 4 6% 8% 54%	3280
	11th to 20th	Day	6% 6% 2 6% 5% 7% 7% 5% 7% 8% 43%	3205
	21st to end	Day	8% 9% 3 6% 5% 4 7% 5% 6% 8% 40%	3200
November	1st to 10th	Day	13% 12% 3 8% 6% 6% 5% 4 6% 6% 31%	1795
	11th to 20th	Day	11% 14% 3 8% 5% 3 5% 4 6% 6% 33%	1656
	21st to end	Day	9% 12% 5% 11% 5% 5% 5% 5% 7% 5% 31%	1600
December	1st to 10th	Day	5% 7% 3 5% 6% 5% 5% 4 7% 7% 45%	2422
	11th to 20th	Day	8% 16% 6% 13% 7% 6% 6% 4 5% 6% 24%	2779
	21st to end	Day	9% 16% 7% 14% 6% 6% 5% 4 6% 6% 21%	4004
January	1st to 10th	Night	8% 16% 6% 13% 7% 6% 5% 4 5% 6% 25%	6306
	11th to 20th	Night	8% 10% 3 6% 4 3 3 3 6% 8% 45%	6282
	21st to end	Night	11% 15% 4 10% 5% 4 4 3 5% 5% 35%	6952
February	1st to 10th	Night	9% 13% 4 8% 5% 4 5% 4 7% 8% 32%	2706
	11th to 20th	Night	7% 10% 4 9% 6% 5% 4 3 5% 8% 39%	2532
	21st to end	Night	7% 11% 5% 10% 5% 5% 5% 5% 7% 7% 33%	1983
March	1st to 10th	Night	4 9% 4 6% 5% 5% 6% 6% 7% 9% 40%	5376
	11th to 20th	Night	4 9% 3 8% 5% 4 4 4 5% 7% 46%	5202
	21st to end	Night	8% 14% 4 9% 6% 6% 6% 5% 6% 8% 30%	5079
April	1st to 10th	Night	8% 9% 3 10% 6% 6% 6% 4 5% 8% 35%	2000
	11th to 20th	Night	6% 10% 3 8% 5% 4 5% 4 5% 6% 43%	1979
	21st to end	Night	6% 10% 2 6% 5% 4 5% 4 7% 7% 44%	1705
May	1st to 10th	Night	4 6% 1 5% 3 3 5% 5% 5% 7% 54%	3640
	11th to 20th	Night	6% 7% 3 6% 4 4 5% 5% 6% 7% 47%	3616
	21st to end	Night	9% 4 2 4 4 4 5% 5% 7% 9% 48%	3972
June	1st to 10th	Night	10% 7% 2 6% 4 6% 6% 4 8% 7% 40%	1600
	11th to 20th	Night	7% 6% 3 6% 5% 5% 4 4 5% 8% 45%	1590
	21st to end	Night	5% 4 1 4 4 4 4 4 6% 8% 57%	1400
July	1st to 10th	Night	2 3 1 3 2 2 2 3 4 4 76%	3566
	11th to 20th	Night	1 1 2 2 2 2 2 4 5% 78%	3640
	21st to end	Night	2 2 1 3 2 3 3 2 5% 7% 71%	3969
August	1st to 10th	Night	2 3 2 4 3 3 3 2 5% 6% 68%	2609
	11th to 20th	Night	2 1 1 3 3 4 4 3 6% 9% 64%	2673
	21st to end	Night	6% 3 1 3 4 4 5% 3 5% 7% 60%	3596
September	1st to 10th	Night	4 3 1 4 3 3 4 4 5% 7% 62%	2000
	11th to 20th	Night	7% 4 2 5% 4 3 3 3 6% 6% 58%	2017
	21st to end	Night	6% 5% 2 5% 4 4 4 4 7% 8% 53%	2218
October	1st to 10th	Night	6% 4 1 4 3 3 4 4 7% 8% 57%	3920
	11th to 20th	Night	7% 6% 2 6% 5% 5% 6% 4 6% 7% 46%	3950
	21st to end	Night	11% 7% 2 5% 5% 5% 5% 4 6% 7% 43%	4600
November	1st to 10th	Night	15% 11% 3 7% 4 4 5% 4 6% 7% 33%	2723
	11th to 20th	Night	11% 12% 3 7% 5% 5% 5% 4 6% 7% 35%	2898
	21st to end	Night	9% 15% 4 10% 7% 6% 5% 5% 5% 6% 30%	2800
December	1st to 10th	Night	5% 9% 3 6% 4 4 3 3 5% 7% 50%	4716
	11th to 20th	Night	7% 17% 6% 12% 6% 6% 5% 5% 6% 8% 22%	5436
	21st to end	Night	10% 18% 6% 12% 5% 5% 5% 3 5% 5% 26%	6952

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	67% 9% 8% 13% 3	3639
	11th to 20th	Day	40% 10% 20% 21% 6% 3	3640
	21st to end	Day	54% 11% 14% 17% 5%	4004
February	1st to 10th	Day	48% 12% 17% 15% 7% 1	1690
	11th to 20th	Day	44% 10% 19% 18% 8%	1764
	21st to end	Day	45% 12% 18% 17% 7% 1	1646
March	1st to 10th	Day	39% 8% 16% 20% 15% 1	4518
	11th to 20th	Day	35% 5% 15% 34% 10% 1	4795
	21st to end	Day	43% 10% 20% 18% 8% 1	5895
April	1st to 10th	Day	44% 9% 16% 22% 7% 2	2400
	11th to 20th	Day	38% 6% 16% 23% 14% 3	2372
	21st to end	Day	38% 8% 14% 24% 12% 3	2694
May	1st to 10th	Day	29% 5% 9% 27% 27% 4	6320
	11th to 20th	Day	36% 8% 16% 27% 11% 1	6280
	21st to end	Day	35% 7% 16% 29% 11% 2	6904
June	1st to 10th	Day	40% 5% 13% 20% 15% 6%	2800
	11th to 20th	Day	38% 6% 16% 22% 15% 3	2800
	21st to end	Day	28% 4 15% 28% 20% 5%	2998
July	1st to 10th	Day	11% 3 9% 25% 30% 22%	6302
	11th to 20th	Day	12% 2 4 25% 29% 28%	6245
	21st to end	Day	16% 3 7% 29% 28% 17%	6681
August	1st to 10th	Day	14% 4 7% 27% 36% 13%	4524
	11th to 20th	Day	17% 4 14% 37% 24% 4	4416
	21st to end	Day	25% 4 13% 30% 21% 6%	4321
September	1st to 10th	Day	19% 5% 13% 29% 27% 7%	2400
	11th to 20th	Day	28% 6% 13% 25% 22% 5%	2382
	21st to end	Day	28% 6% 17% 31% 16% 3	2180
October	1st to 10th	Day	23% 5% 19% 37% 15% 1	3280
	11th to 20th	Day	32% 9% 17% 26% 15% 1	3205
	21st to end	Day	37% 9% 17% 23% 14%	3200
November	1st to 10th	Day	47% 11% 16% 16% 9% 1	1795
	11th to 20th	Day	51% 10% 17% 16% 5% 1	1656
	21st to end	Day	55% 11% 14% 13% 6% 1	1600
December	1st to 10th	Day	42% 16% 21% 18% 3	2422
	11th to 20th	Day	66% 9% 10% 9% 5% 1	2782
	21st to end	Day	71% 10% 8% 8% 3	4004
January	1st to 10th	Night	66% 9% 11% 12% 2	6306
	11th to 20th	Night	37% 10% 21% 23% 8% 1	6320
	21st to end	Night	58% 9% 15% 14% 4	6952
February	1st to 10th	Night	51% 12% 15% 13% 7% 2	2706
	11th to 20th	Night	43% 11% 17% 20% 8% 1	2534
	21st to end	Night	44% 12% 17% 17% 9% 1	1983
March	1st to 10th	Night	34% 8% 18% 27% 13% 1	5376
	11th to 20th	Night	36% 4 16% 29% 13% 2	5203
	21st to end	Night	47% 9% 20% 18% 5% 1	5079
April	1st to 10th	Night	41% 7% 18% 24% 8% 2	2000
	11th to 20th	Night	35% 6% 14% 24% 17% 4	1979
	21st to end	Night	32% 7% 13% 29% 15% 3	1705
May	1st to 10th	Night	23% 5% 8% 29% 31% 3	3637
	11th to 20th	Night	30% 7% 13% 31% 17% 3	3616
	21st to end	Night	24% 7% 20% 33% 14% 1	3972
June	1st to 10th	Night	33% 6% 13% 24% 18% 6%	1600
	11th to 20th	Night	31% 7% 15% 27% 17% 4	1590
	21st to end	Night	22% 5% 16% 30% 22% 5%	1400
July	1st to 10th	Night	12% 2 5% 25% 29% 27%	3526
	11th to 20th	Night	7% 2 5% 28% 28% 29%	3592
	21st to end	Night	12% 3 5% 29% 32% 18%	3857
August	1st to 10th	Night	16% 4 7% 24% 32% 16%	2601
	11th to 20th	Night	15% 4 13% 37% 26% 4	2697
	21st to end	Night	21% 4 12% 32% 24% 6%	3596
September	1st to 10th	Night	17% 4 13% 30% 27% 8%	2000
	11th to 20th	Night	23% 5% 13% 28% 25% 6%	2017
	21st to end	Night	25% 6% 16% 34% 16% 5%	2218
October	1st to 10th	Night	21% 4 16% 38% 18% 2	3920
	11th to 20th	Night	33% 8% 15% 26% 16% 1	3950
	21st to end	Night	37% 7% 15% 28% 11% 1	4600
November	1st to 10th	Night	46% 9% 19% 16% 8% 2	2723
	11th to 20th	Night	47% 12% 17% 15% 6% 2	2898
	21st to end	Night	58% 11% 14% 12% 6%	2800
December	1st to 10th	Night	41% 15% 20% 22% 2	4716
	11th to 20th	Night	67% 9% 13% 8% 4	5432
	21st to end	Night	65% 11% 9% 11% 4	6952

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	15% 15% 33% 20% 13% 5%	200
	11th to 20th	Day	19% 13% 26% 25% 14% 4	200
	21st to end	Day	20% 9% 29% 30% 10% 2	220
February	1st to 10th	Day	9% 16% 46% 22% 7%	290
	11th to 20th	Day	12% 17% 36% 27% 7% 1	395
	21st to end	Day	10% 20% 38% 23% 8% 1	412
March	1st to 10th	Day	16% 17% 39% 19% 8% 1	500
	11th to 20th	Day	15% 23% 27% 20% 14% 1	500
	21st to end	Day	17% 22% 32% 21% 8%	550
April	1st to 10th	Day	21% 20% 31% 20% 7% 1	500
	11th to 20th	Day	17% 26% 29% 18% 8% 3	492
	21st to end	Day	14% 22% 28% 23% 10% 2	500
May	1st to 10th	Day	12% 19% 34% 28% 7% 1	503
	11th to 20th	Day	20% 14% 25% 27% 12% 2	528
	21st to end	Day	15% 16% 27% 26% 13% 3	573
June	1st to 10th	Day	16% 18% 35% 23% 8% 2	530
	11th to 20th	Day	15% 21% 32% 22% 8% 1	530
	21st to end	Day	11% 12% 35% 26% 15% 1	728
July	1st to 10th	Day	6% 13% 35% 33% 11% 1	551
	11th to 20th	Day	7% 18% 34% 27% 12% 3	524
	21st to end	Day	4 11% 34% 32% 15% 3	575
August	1st to 10th	Day	5% 11% 31% 33% 16% 5%	527
	11th to 20th	Day	5% 9% 30% 29% 21% 6%	517
	21st to end	Day	8% 13% 32% 30% 13% 5%	583
September	1st to 10th	Day	7% 11% 33% 30% 14% 5%	530
	11th to 20th	Day	9% 14% 31% 27% 14% 4	530
	21st to end	Day	13% 18% 33% 25% 9% 2	530
October	1st to 10th	Day	11% 15% 37% 22% 15% 1	530
	11th to 20th	Day	12% 19% 31% 24% 11% 3	499
	21st to end	Day	14% 20% 34% 22% 9% 2	363
November	1st to 10th	Day	16% 18% 31% 27% 8% 1	299
	11th to 20th	Day	12% 24% 31% 21% 10% 2	214
	21st to end	Day	12% 14% 32% 27% 13% 4	200
December	1st to 10th	Day	15% 10% 26% 23% 19% 9%	200
	11th to 20th	Day	12% 11% 37% 31% 8% 3	200
	21st to end	Day	10% 10% 32% 35% 11% 2	220
January	1st to 10th	Night	18% 9% 33% 26% 13% 2	800
	11th to 20th	Night	17% 8% 28% 32% 13% 2	800
	21st to end	Night	14% 5% 31% 34% 15% 1	880
February	1st to 10th	Night	13% 7% 35% 34% 10% 2	800
	11th to 20th	Night	11% 7% 33% 36% 13% 1	784
	21st to end	Night	11% 11% 30% 30% 16% 2	660
March	1st to 10th	Night	12% 6% 30% 34% 16% 1	800
	11th to 20th	Night	11% 8% 30% 35% 15% 1	800
	21st to end	Night	11% 8% 31% 37% 12% 1	880
April	1st to 10th	Night	12% 7% 28% 37% 17% 1	800
	11th to 20th	Night	9% 9% 29% 35% 15% 2	791
	21st to end	Night	8% 8% 35% 34% 14%	505
May	1st to 10th	Night	8% 8% 33% 35% 16% 1	400
	11th to 20th	Night	10% 7% 21% 38% 23% 2	394
	21st to end	Night	13% 4 21% 37% 22% 3	433
June	1st to 10th	Night	10% 7% 27% 39% 16% 1	400
	11th to 20th	Night	9% 8% 31% 35% 17% 1	400
	21st to end	Night	5% 4 30% 36% 24% 2	400
July	1st to 10th	Night	6% 6% 21% 41% 26% 1	390
	11th to 20th	Night	2 4 29% 42% 21% 1	388
	21st to end	Night	2 2 20% 44% 30% 1	438
August	1st to 10th	Night	4 4 19% 37% 33% 3	398
	11th to 20th	Night	3 3 20% 36% 34% 4	453
	21st to end	Night	6% 5% 22% 41% 24% 2	868
September	1st to 10th	Night	6% 4 20% 43% 24% 3	800
	11th to 20th	Night	8% 4 19% 33% 30% 7%	800
	21st to end	Night	9% 7% 26% 34% 22% 4	800
October	1st to 10th	Night	12% 6% 23% 35% 23% 2	800
	11th to 20th	Night	10% 7% 28% 37% 16% 2	800
	21st to end	Night	17% 10% 29% 31% 11% 3	880
November	1st to 10th	Night	19% 7% 29% 36% 8%	820
	11th to 20th	Night	16% 10% 29% 31% 12% 2	828
	21st to end	Night	16% 7% 30% 30% 14% 3	800
December	1st to 10th	Night	13% 7% 26% 37% 15% 2	891
	11th to 20th	Night	18% 8% 31% 33% 10% 1	950
	21st to end	Night	19% 9% 29% 36% 7%	880

Page generated at 2025-11-14 21:55:54. Version ac07

Copyright © 2025 Attilla Danko.