Wakely Mountain
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Wakely Mountain clear sky chart from 2005-11-06 to 2025-02-21.

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	16% 13% 5% 11% 6% 5% 5% 4 5% 6% 26%	108641
	Night	14% 15% 6% 13% 7% 5% 4 3 4 5% 24%	109938
Transparency	Day	55% 8% 11% 17% 9% 1	112154
	Night	58% 8% 10% 14% 8% 1	114589
Seeing	Day	26% 20% 29% 16% 7% 2	14948
	Night	23% 20% 28% 20% 8% 1	24166

By Month

Percentage Cloud Cover NE (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	7% 15% 9% 22% 14% 8% 4 2 2 3 14%	3597
	11th to 20th	Day	8% 16% 8% 24% 15% 7% 3 2 2 3 13%	3570
	21st to end	Day	10% 17% 8% 17% 7% 5% 7% 4 4 4 16%	4116
February	1st to 10th	Day	11% 18% 8% 14% 10% 6% 5% 4 4 4 17%	1800
	11th to 20th	Day	8% 14% 8% 19% 11% 5% 4 3 4 4 20%	1857
	21st to end	Day	13% 17% 6% 14% 6% 6% 4 3 5% 5% 20%	1570
March	1st to 10th	Day	18% 19% 6% 14% 6% 3 4 2 4 4 20%	3116
	11th to 20th	Day	10% 19% 12% 13% 6% 4 4 2 4 4 22%	3370
	21st to end	Day	14% 14% 6% 12% 6% 3 3 2 3 4 32%	4116
April	1st to 10th	Day	17% 18% 5% 8% 4 3 3 3 4 4 29%	2280
	11th to 20th	Day	16% 16% 4 8% 4 4 4 3 4 5% 32%	2254
	21st to end	Day	21% 16% 4 7% 5% 4 4 3 4 5% 27%	2353
May	1st to 10th	Day	23% 13% 3 8% 5% 4 4 4 4 6% 26%	4344
	11th to 20th	Day	18% 11% 3 9% 5% 6% 5% 4 6% 7% 26%	4398
	21st to end	Day	15% 8% 3 7% 5% 5% 5% 4 6% 7% 36%	4837
June	1st to 10th	Day	22% 8% 3 8% 6% 6% 5% 3 5% 6% 27%	2660
	11th to 20th	Day	20% 9% 2 7% 4 5% 5% 5% 7% 7% 29%	2660
	21st to end	Day	21% 10% 3 8% 5% 5% 4 4 5% 7% 27%	2660
July	1st to 10th	Day	15% 8% 2 7% 5% 5% 5% 5% 7% 10% 32%	4440
	11th to 20th	Day	12% 9% 3 7% 5% 5% 6% 5% 8% 10% 30%	4440
	21st to end	Day	15% 8% 3 7% 5% 6% 6% 5% 6% 7% 32%	4814
August	1st to 10th	Day	18% 9% 3 6% 4 5% 5% 4 7% 8% 31%	4395
	11th to 20th	Day	17% 10% 4 8% 5% 5% 6% 5% 7% 8% 26%	3826
	21st to end	Day	16% 8% 2 7% 4 5% 5% 4 6% 8% 34%	4180
September	1st to 10th	Day	17% 8% 2 6% 4 5% 5% 3 5% 8% 37%	2280
	11th to 20th	Day	16% 8% 2 6% 4 4 4 3 5% 6% 43%	2227
	21st to end	Day	18% 8% 3 6% 5% 4 4 4 5% 7% 34%	2090
October	1st to 10th	Day	25% 12% 3 7% 4 4 5% 3 4 4 29%	1928
	11th to 20th	Day	18% 16% 4 7% 4 4 4 4 6% 6% 28%	1900
	21st to end	Day	23% 18% 4 8% 4 4 4 3 4 5% 23%	1906
November	1st to 10th	Day	13% 18% 5% 9% 5% 4 4 4 4 5% 27%	1761
	11th to 20th	Day	13% 18% 7% 10% 6% 4 4 4 4 4 27%	1750
	21st to end	Day	15% 19% 7% 12% 6% 5% 5% 3 4 5% 20%	1600
December	1st to 10th	Day	11% 25% 10% 23% 9% 4 3 2 3 2 11%	2600
	11th to 20th	Day	14% 18% 8% 21% 7% 4 3 3 4 3 16%	2986
	21st to end	Day	14% 18% 8% 14% 6% 5% 3 3 4 5% 20%	3960
January	1st to 10th	Night	9% 15% 9% 24% 10% 9% 4 3 3 3 12%	6349
	11th to 20th	Night	6% 16% 10% 26% 16% 6% 4 2 3 2 8%	6315
	21st to end	Night	10% 13% 8% 20% 10% 8% 8% 3 4 4 12%	6837
February	1st to 10th	Night	10% 17% 7% 18% 12% 7% 4 3 4 4 14%	2600
	11th to 20th	Night	8% 12% 7% 18% 11% 7% 6% 4 5% 5% 16%	2428
	21st to end	Night	12% 15% 5% 14% 9% 7% 3 4 4 6% 20%	1885
March	1st to 10th	Night	17% 14% 6% 11% 8% 6% 4 3 4 4 23%	3724
	11th to 20th	Night	12% 19% 9% 12% 5% 3 3 3 3 5% 26%	3585
	21st to end	Night	14% 15% 7% 11% 7% 4 4 2 3 4 29%	3515
April	1st to 10th	Night	16% 16% 6% 10% 6% 4 4 4 4 5% 26%	1900
	11th to 20th	Night	17% 17% 5% 7% 4 4 3 3 4 7% 29%	1875
	21st to end	Night	20% 14% 4 7% 4 3 4 3 4 6% 31%	1825
May	1st to 10th	Night	22% 15% 3 7% 4 4 4 4 5% 6% 26%	2624
	11th to 20th	Night	19% 14% 3 8% 5% 4 3 4 4 5% 31%	2495
	21st to end	Night	15% 9% 2 6% 5% 4 5% 4 6% 8% 37%	2738
June	1st to 10th	Night	22% 7% 3 6% 4 4 5% 4 4 7% 34%	1520
	11th to 20th	Night	21% 8% 2 5% 4 4 5% 3 6% 7% 37%	1520
	21st to end	Night	21% 7% 3 6% 5% 4 3 4 6% 8% 34%	1520
July	1st to 10th	Night	14% 8% 3 7% 5% 5% 5% 4 6% 8% 36%	2520
	11th to 20th	Night	15% 10% 3 5% 4 3 5% 4 5% 7% 39%	2520
	21st to end	Night	13% 10% 3 6% 4 4 4 3 6% 8% 40%	2739
August	1st to 10th	Night	22% 11% 3 6% 3 3 4 2 4 5% 37%	2531
	11th to 20th	Night	20% 13% 3 6% 4 3 3 3 4 6% 33%	2969
	21st to end	Night	11% 14% 2 5% 3 3 5% 4 5% 7% 41%	3476
September	1st to 10th	Night	14% 8% 3 6% 4 4 4 3 5% 6% 42%	1900
	11th to 20th	Night	13% 8% 3 6% 4 3 3 4 4 5% 47%	1952
	21st to end	Night	18% 10% 3 6% 4 3 4 3 5% 6% 38%	2090
October	1st to 10th	Night	20% 14% 3 7% 5% 5% 4 4 4 5% 29%	2250
	11th to 20th	Night	18% 14% 4 7% 5% 4 5% 4 5% 6% 30%	2280
	21st to end	Night	22% 20% 4 8% 4 4 4 3 4 5% 22%	2690
November	1st to 10th	Night	14% 17% 6% 9% 5% 4 5% 3 5% 5% 27%	2537
	11th to 20th	Night	13% 17% 6% 11% 5% 5% 4 4 5% 5% 24%	2645
	21st to end	Night	14% 18% 7% 14% 6% 5% 4 4 5% 5% 18%	2800
December	1st to 10th	Night	13% 22% 10% 26% 7% 3 3 2 3 3 9%	4580
	11th to 20th	Night	16% 18% 11% 16% 8% 4 4 2 3 3 15%	5208
	21st to end	Night	15% 19% 6% 17% 6% 5% 4 3 3 4 17%	6996

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	68% 13% 6% 8% 5%	3598
	11th to 20th	Day	75% 7% 4 5% 6% 3	3600
	21st to end	Day	65% 10% 9% 9% 6% 2	4116
February	1st to 10th	Day	69% 7% 8% 11% 4 1	1800
	11th to 20th	Day	66% 6% 8% 10% 9% 1	1866
	21st to end	Day	63% 7% 9% 11% 9% 1	1570
March	1st to 10th	Day	65% 7% 9% 8% 9% 2	3119
	11th to 20th	Day	63% 8% 10% 10% 8% 1	3370
	21st to end	Day	53% 7% 7% 15% 16% 2	4116
April	1st to 10th	Day	58% 5% 9% 16% 11% 2	2280
	11th to 20th	Day	54% 6% 9% 18% 12% 1	2254
	21st to end	Day	58% 5% 10% 12% 11% 3	2353
May	1st to 10th	Day	55% 9% 9% 18% 8% 1	4358
	11th to 20th	Day	52% 10% 13% 18% 7% 1	4402
	21st to end	Day	43% 10% 13% 25% 9% 1	4837
June	1st to 10th	Day	55% 8% 12% 14% 10% 1	2660
	11th to 20th	Day	50% 9% 12% 19% 9% 1	2660
	21st to end	Day	54% 8% 13% 17% 7% 1	2660
July	1st to 10th	Day	43% 9% 16% 23% 10%	4370
	11th to 20th	Day	42% 11% 15% 25% 6%	4365
	21st to end	Day	47% 9% 12% 25% 7%	4661
August	1st to 10th	Day	47% 9% 15% 19% 10%	4381
	11th to 20th	Day	49% 11% 16% 20% 4	3865
	21st to end	Day	43% 9% 15% 25% 8%	4180
September	1st to 10th	Day	43% 7% 13% 26% 10% 1	2280
	11th to 20th	Day	41% 6% 11% 25% 16% 1	2227
	21st to end	Day	47% 8% 13% 20% 12% 1	2090
October	1st to 10th	Day	52% 7% 10% 21% 10% 1	3201
	11th to 20th	Day	48% 6% 13% 16% 15% 3	3140
	21st to end	Day	48% 7% 15% 23% 7% 1	3118
November	1st to 10th	Day	56% 8% 11% 15% 10%	1761
	11th to 20th	Day	57% 7% 10% 13% 11% 3	1750
	21st to end	Day	64% 8% 13% 10% 5% 1	1600
December	1st to 10th	Day	79% 5% 5% 8% 2	2600
	11th to 20th	Day	69% 9% 7% 10% 5%	2986
	21st to end	Day	65% 6% 6% 8% 13% 2	3960
January	1st to 10th	Night	71% 12% 6% 7% 4	6349
	11th to 20th	Night	78% 8% 6% 4 3 1	6360
	21st to end	Night	67% 12% 8% 7% 5% 1	6837
February	1st to 10th	Night	71% 7% 8% 9% 5% 1	2600
	11th to 20th	Night	65% 8% 9% 10% 7% 1	2430
	21st to end	Night	60% 8% 11% 12% 8% 1	1885
March	1st to 10th	Night	60% 9% 10% 11% 9% 1	3734
	11th to 20th	Night	58% 8% 11% 15% 7% 1	3586
	21st to end	Night	57% 6% 7% 16% 13% 2	3515
April	1st to 10th	Night	58% 6% 10% 15% 9% 1	1900
	11th to 20th	Night	53% 8% 10% 17% 11%	1875
	21st to end	Night	53% 7% 9% 17% 12% 2	1825
May	1st to 10th	Night	55% 10% 10% 15% 9% 1	2630
	11th to 20th	Night	53% 9% 12% 18% 8% 1	2496
	21st to end	Night	42% 10% 13% 21% 13% 1	2739
June	1st to 10th	Night	48% 7% 15% 20% 9% 1	1520
	11th to 20th	Night	45% 7% 15% 21% 11% 1	1520
	21st to end	Night	46% 8% 14% 21% 9%	1520
July	1st to 10th	Night	43% 9% 15% 18% 14% 1	2480
	11th to 20th	Night	39% 12% 15% 25% 9%	2472
	21st to end	Night	40% 8% 14% 28% 8% 1	2651
August	1st to 10th	Night	49% 7% 15% 22% 7%	2521
	11th to 20th	Night	47% 9% 15% 22% 6%	2996
	21st to end	Night	38% 10% 14% 30% 8% 1	3476
September	1st to 10th	Night	39% 9% 14% 26% 10% 1	1900
	11th to 20th	Night	37% 6% 14% 29% 13% 1	1952
	21st to end	Night	44% 7% 12% 22% 12% 2	2090
October	1st to 10th	Night	53% 9% 10% 19% 9% 1	3757
	11th to 20th	Night	48% 7% 12% 18% 9% 7%	3779
	21st to end	Night	53% 8% 12% 20% 6% 1	4428
November	1st to 10th	Night	56% 8% 11% 14% 9% 2	2537
	11th to 20th	Night	57% 7% 10% 13% 9% 3	2645
	21st to end	Night	64% 9% 11% 11% 5% 1	2800
December	1st to 10th	Night	80% 6% 7% 5% 2	4580
	11th to 20th	Night	72% 6% 6% 8% 7%	5208
	21st to end	Night	69% 7% 6% 5% 9% 4	6996

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% 26% 32% 9% 5%	200
	11th to 20th	Day	30% 29% 34% 6% 1 1	200
	21st to end	Day	27% 32% 28% 10% 3	253
February	1st to 10th	Day	38% 34% 24% 4	300
	11th to 20th	Day	36% 29% 28% 6% 1	404
	21st to end	Day	35% 24% 30% 9% 1	382
March	1st to 10th	Day	29% 27% 29% 12% 3	460
	11th to 20th	Day	30% 27% 27% 12% 3 1	460
	21st to end	Day	33% 27% 21% 13% 5% 1	506
April	1st to 10th	Day	36% 24% 25% 9% 6% 1	460
	11th to 20th	Day	34% 24% 20% 14% 5% 2	452
	21st to end	Day	34% 19% 29% 11% 5% 3	460
May	1st to 10th	Day	33% 20% 27% 11% 6% 4	463
	11th to 20th	Day	22% 18% 32% 20% 7% 2	487
	21st to end	Day	21% 18% 32% 16% 12% 2	529
June	1st to 10th	Day	24% 19% 31% 18% 6% 2	490
	11th to 20th	Day	21% 16% 31% 20% 9% 2	490
	21st to end	Day	25% 19% 31% 17% 6% 2	490
July	1st to 10th	Day	17% 11% 33% 23% 13% 3	485
	11th to 20th	Day	13% 12% 37% 25% 10% 2	484
	21st to end	Day	16% 13% 39% 24% 7% 2	532
August	1st to 10th	Day	15% 14% 30% 25% 11% 5%	486
	11th to 20th	Day	16% 12% 33% 22% 11% 6%	479
	21st to end	Day	14% 18% 31% 22% 10% 6%	539
September	1st to 10th	Day	20% 11% 29% 21% 12% 7%	490
	11th to 20th	Day	14% 15% 25% 19% 14% 12%	490
	21st to end	Day	17% 17% 31% 19% 12% 5%	490
October	1st to 10th	Day	29% 15% 26% 15% 12% 4	490
	11th to 20th	Day	24% 24% 28% 16% 7% 1	490
	21st to end	Day	33% 21% 26% 16% 4	442
November	1st to 10th	Day	30% 22% 26% 17% 6% 1	395
	11th to 20th	Day	31% 24% 27% 12% 5% 1	350
	21st to end	Day	39% 24% 28% 10% 1	200
December	1st to 10th	Day	37% 23% 30% 8% 3	200
	11th to 20th	Day	37% 28% 28% 6% 1 1	200
	21st to end	Day	33% 28% 30% 7% 2	220
January	1st to 10th	Night	25% 29% 32% 13% 1	800
	11th to 20th	Night	27% 27% 30% 13% 2 1	800
	21st to end	Night	20% 29% 33% 15% 4	880
February	1st to 10th	Night	25% 29% 32% 13% 1	800
	11th to 20th	Night	25% 30% 31% 12% 2	783
	21st to end	Night	26% 26% 34% 12% 2	629
March	1st to 10th	Night	28% 23% 31% 16% 2	760
	11th to 20th	Night	29% 24% 27% 16% 3 1	760
	21st to end	Night	23% 25% 28% 17% 6%	836
April	1st to 10th	Night	25% 23% 31% 18% 3	760
	11th to 20th	Night	26% 23% 27% 16% 7% 1	751
	21st to end	Night	28% 20% 25% 21% 6% 1	685
May	1st to 10th	Night	26% 16% 26% 22% 9%	451
	11th to 20th	Night	17% 17% 32% 27% 7% 1	374
	21st to end	Night	14% 12% 32% 30% 12% 1	411
June	1st to 10th	Night	21% 12% 28% 28% 11% 1	380
	11th to 20th	Night	20% 11% 24% 30% 14%	380
	21st to end	Night	20% 11% 32% 29% 9% 1	380
July	1st to 10th	Night	13% 6% 27% 37% 15% 1	370
	11th to 20th	Night	13% 5% 29% 34% 17% 2	368
	21st to end	Night	13% 9% 26% 41% 11% 1	416
August	1st to 10th	Night	16% 7% 23% 37% 16% 1	390
	11th to 20th	Night	16% 8% 25% 30% 20% 2	670
	21st to end	Night	16% 9% 26% 31% 17% 1	836
September	1st to 10th	Night	16% 12% 25% 30% 15% 2	760
	11th to 20th	Night	17% 9% 23% 27% 20% 4	760
	21st to end	Night	21% 13% 24% 23% 18% 2	760
October	1st to 10th	Night	25% 17% 23% 19% 15% 2	760
	11th to 20th	Night	25% 17% 26% 24% 8% 1	760
	21st to end	Night	32% 22% 25% 18% 3	836
November	1st to 10th	Night	25% 22% 30% 17% 6%	780
	11th to 20th	Night	28% 24% 27% 14% 7% 1	800
	21st to end	Night	28% 26% 26% 15% 4 1	800
December	1st to 10th	Night	28% 30% 27% 12% 3	800
	11th to 20th	Night	29% 28% 26% 14% 3 1	800
	21st to end	Night	28% 30% 26% 12% 4	880

Page generated at 2025-02-18 03:26:33. Version ac07

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