Manic-5
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Manic-5 clear sky chart from 2005-11-06 to 2025-05-26.

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	17% 13% 4 10% 6% 5% 5% 4 5% 6% 23%	113681
	Night	15% 14% 5% 11% 7% 6% 5% 4 6% 6% 22%	115700
Transparency	Day	60% 5% 10% 16% 8% 1	117109
	Night	61% 5% 11% 16% 7%	120438
Seeing	Day	27% 17% 29% 18% 7% 2	16533
	Night	24% 15% 31% 22% 8% 1	24493

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	10% 21% 9% 15% 8% 4 4 3 4 4 17%	3157
	11th to 20th	Day	6% 16% 7% 15% 10% 9% 6% 4 7% 6% 14%	3218
	21st to end	Day	4 7% 3 13% 7% 6% 6% 7% 10% 8% 30%	3960
February	1st to 10th	Day	5% 11% 5% 10% 9% 8% 8% 4 8% 9% 23%	1610
	11th to 20th	Day	7% 17% 6% 13% 8% 6% 6% 5% 7% 6% 18%	1753
	21st to end	Day	5% 15% 5% 12% 10% 6% 7% 6% 7% 7% 21%	1620
March	1st to 10th	Day	14% 13% 4 11% 7% 6% 5% 4 4 5% 26%	4476
	11th to 20th	Day	15% 21% 5% 12% 6% 6% 5% 4 4 4 17%	4934
	21st to end	Day	15% 17% 7% 11% 5% 5% 4 3 4 6% 24%	5551
April	1st to 10th	Day	16% 17% 6% 13% 6% 6% 4 3 3 3 22%	2456
	11th to 20th	Day	15% 15% 4 10% 6% 5% 5% 4 4 5% 27%	2572
	21st to end	Day	19% 15% 4 10% 6% 5% 3 2 4 5% 26%	2600
May	1st to 10th	Day	20% 17% 4 9% 5% 4 4 4 5% 4 24%	4429
	11th to 20th	Day	25% 9% 3 8% 5% 5% 5% 4 5% 6% 25%	4865
	21st to end	Day	25% 15% 3 8% 5% 4 4 4 4 5% 23%	5260
June	1st to 10th	Day	24% 10% 3 7% 5% 4 4 3 5% 5% 29%	2850
	11th to 20th	Day	20% 8% 3 8% 6% 5% 6% 5% 6% 6% 27%	2850
	21st to end	Day	28% 9% 3 8% 6% 4 5% 3 5% 5% 23%	2850
July	1st to 10th	Day	17% 8% 3 8% 5% 6% 5% 5% 6% 7% 31%	4760
	11th to 20th	Day	17% 7% 3 8% 6% 6% 7% 5% 7% 7% 27%	4760
	21st to end	Day	14% 7% 3 8% 6% 6% 7% 5% 7% 9% 28%	5037
August	1st to 10th	Day	18% 8% 3 9% 6% 7% 7% 5% 7% 7% 25%	4402
	11th to 20th	Day	19% 10% 4 10% 7% 6% 6% 5% 6% 6% 20%	4045
	21st to end	Day	18% 8% 3 8% 6% 5% 6% 4 5% 7% 30%	4532
September	1st to 10th	Day	21% 9% 3 9% 6% 4 5% 4 5% 6% 29%	2337
	11th to 20th	Day	29% 8% 3 7% 4 4 4 3 4 6% 27%	2090
	21st to end	Day	23% 12% 4 8% 6% 5% 5% 3 4 5% 27%	2090
October	1st to 10th	Day	23% 13% 3 9% 5% 6% 4 2 5% 5% 24%	1987
	11th to 20th	Day	28% 18% 5% 10% 5% 4 4 3 4 5% 16%	1777
	21st to end	Day	26% 20% 5% 10% 4 5% 4 2 3 5% 16%	1881
November	1st to 10th	Day	18% 20% 8% 13% 7% 6% 4 4 4 4 12%	1639
	11th to 20th	Day	19% 20% 5% 14% 9% 5% 4 3 3 4 14%	1559
	21st to end	Day	16% 24% 8% 13% 7% 5% 4 3 3 5% 14%	1400
December	1st to 10th	Day	11% 17% 7% 18% 11% 7% 5% 3 4 5% 13%	2280
	11th to 20th	Day	14% 14% 6% 15% 9% 7% 7% 4 5% 5% 14%	2618
	21st to end	Day	12% 15% 6% 12% 7% 6% 7% 4 5% 7% 20%	3476
January	1st to 10th	Night	10% 24% 9% 17% 7% 6% 5% 3 3 4 12%	6808
	11th to 20th	Night	7% 17% 6% 15% 10% 9% 6% 5% 6% 6% 12%	6679
	21st to end	Night	4 7% 3 10% 7% 6% 7% 8% 11% 10% 26%	6996
February	1st to 10th	Night	5% 12% 4 12% 9% 8% 8% 5% 9% 7% 21%	2789
	11th to 20th	Night	8% 16% 6% 14% 8% 5% 7% 5% 7% 7% 17%	2533
	21st to end	Night	7% 15% 6% 11% 8% 6% 8% 6% 7% 7% 21%	2007
March	1st to 10th	Night	13% 14% 5% 11% 6% 6% 5% 4 5% 7% 25%	5364
	11th to 20th	Night	16% 19% 6% 14% 7% 6% 6% 4 4 4 16%	5011
	21st to end	Night	13% 19% 6% 10% 6% 6% 6% 3 5% 5% 21%	5377
April	1st to 10th	Night	17% 16% 5% 11% 5% 5% 5% 4 5% 5% 23%	1943
	11th to 20th	Night	16% 12% 4 9% 6% 4 4 3 4 5% 33%	1778
	21st to end	Night	20% 13% 4 8% 7% 5% 4 3 4 4 27%	1800
May	1st to 10th	Night	22% 19% 5% 9% 5% 4 4 3 4 4 21%	2751
	11th to 20th	Night	22% 9% 3 8% 6% 4 4 3 5% 6% 29%	2258
	21st to end	Night	24% 14% 4 8% 5% 4 4 4 5% 5% 23%	2442
June	1st to 10th	Night	20% 10% 2 8% 6% 5% 4 3 6% 7% 30%	1330
	11th to 20th	Night	20% 9% 3 7% 6% 5% 5% 5% 6% 6% 27%	1330
	21st to end	Night	25% 9% 3 6% 4 4 5% 4 6% 7% 26%	1330
July	1st to 10th	Night	16% 6% 2 6% 4 5% 6% 5% 10% 10% 29%	2210
	11th to 20th	Night	13% 6% 2 8% 6% 5% 6% 5% 8% 11% 30%	2210
	21st to end	Night	11% 5% 2 7% 4 6% 7% 6% 8% 10% 34%	2519
August	1st to 10th	Night	17% 8% 3 7% 4 5% 5% 4 7% 9% 32%	2506
	11th to 20th	Night	21% 9% 3 9% 6% 8% 7% 5% 6% 5% 22%	2773
	21st to end	Night	13% 6% 3 7% 5% 5% 4 4 6% 7% 40%	3124
September	1st to 10th	Night	22% 8% 3 7% 5% 4 5% 4 6% 6% 32%	1841
	11th to 20th	Night	23% 8% 3 8% 4 4 4 3 4 5% 32%	2090
	21st to end	Night	20% 10% 3 7% 5% 4 5% 4 5% 6% 32%	2090
October	1st to 10th	Night	21% 11% 3 9% 5% 5% 4 3 5% 5% 30%	2192
	11th to 20th	Night	26% 15% 4 11% 5% 4 3 3 4 5% 20%	2400
	21st to end	Night	26% 15% 5% 10% 5% 4 5% 3 4 5% 17%	2717
November	1st to 10th	Night	21% 17% 5% 12% 7% 5% 5% 4 5% 5% 15%	2659
	11th to 20th	Night	18% 19% 6% 14% 6% 5% 5% 3 5% 5% 15%	2840
	21st to end	Night	19% 20% 7% 15% 9% 6% 4 3 4 4 11%	3000
December	1st to 10th	Night	10% 16% 7% 18% 10% 6% 5% 3 4 4 16%	4910
	11th to 20th	Night	16% 14% 6% 15% 8% 6% 5% 4 4 5% 17%	5591
	21st to end	Night	11% 16% 5% 11% 7% 6% 5% 5% 6% 9% 17%	7502

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	71% 3 8% 14% 4	3158
	11th to 20th	Day	67% 4 12% 13% 5%	3244
	21st to end	Day	45% 7% 10% 21% 17% 1	3960
February	1st to 10th	Day	56% 5% 9% 18% 12% 1	1610
	11th to 20th	Day	63% 4 10% 14% 9%	1761
	21st to end	Day	59% 5% 8% 18% 9% 1	1620
March	1st to 10th	Day	61% 3 7% 17% 11% 1	4479
	11th to 20th	Day	70% 5% 5% 11% 8% 1	4934
	21st to end	Day	61% 4 7% 15% 12% 2	5551
April	1st to 10th	Day	68% 4 6% 13% 10%	2456
	11th to 20th	Day	59% 4 8% 16% 12% 1	2572
	21st to end	Day	62% 4 9% 15% 10% 1	2600
May	1st to 10th	Day	61% 7% 8% 15% 9% 1	4443
	11th to 20th	Day	56% 7% 10% 18% 8% 1	4869
	21st to end	Day	62% 4 9% 16% 8%	5260
June	1st to 10th	Day	56% 6% 8% 18% 10% 3	2850
	11th to 20th	Day	55% 7% 10% 15% 11% 1	2850
	21st to end	Day	62% 6% 8% 15% 8% 1	2850
July	1st to 10th	Day	50% 6% 10% 23% 10%	4685
	11th to 20th	Day	52% 7% 15% 16% 10% 1	4679
	21st to end	Day	49% 8% 15% 20% 6% 1	4877
August	1st to 10th	Day	54% 8% 15% 17% 5%	4388
	11th to 20th	Day	61% 7% 14% 14% 3	4084
	21st to end	Day	53% 6% 14% 19% 8% 1	4532
September	1st to 10th	Day	55% 7% 14% 18% 6%	2337
	11th to 20th	Day	57% 5% 15% 19% 4	2090
	21st to end	Day	59% 5% 11% 19% 6%	2090
October	1st to 10th	Day	61% 4 11% 18% 5%	3299
	11th to 20th	Day	71% 4 10% 14% 2	2928
	21st to end	Day	64% 4 13% 15% 4 1	3081
November	1st to 10th	Day	75% 6% 9% 9% 2	1639
	11th to 20th	Day	74% 4 10% 10% 1	1559
	21st to end	Day	74% 4 11% 9% 2	1400
December	1st to 10th	Day	74% 5% 11% 5% 5%	2280
	11th to 20th	Day	68% 5% 13% 11% 4	2618
	21st to end	Day	61% 5% 7% 20% 5% 1	3476
January	1st to 10th	Night	76% 3 7% 10% 3	6808
	11th to 20th	Night	67% 5% 12% 12% 3	6728
	21st to end	Night	43% 8% 13% 22% 12% 1	6996
February	1st to 10th	Night	57% 4 9% 17% 11% 2	2789
	11th to 20th	Night	62% 4 9% 16% 8%	2536
	21st to end	Night	60% 4 11% 16% 9% 1	2007
March	1st to 10th	Night	57% 4 7% 16% 15%	5374
	11th to 20th	Night	72% 4 6% 11% 6% 1	5012
	21st to end	Night	64% 5% 5% 13% 12% 1	5377
April	1st to 10th	Night	62% 5% 8% 12% 12% 1	1943
	11th to 20th	Night	53% 5% 9% 16% 15% 2	1778
	21st to end	Night	60% 4 9% 15% 11%	1800
May	1st to 10th	Night	64% 7% 8% 14% 7%	2757
	11th to 20th	Night	55% 5% 11% 19% 9%	2259
	21st to end	Night	62% 5% 9% 19% 6%	2443
June	1st to 10th	Night	53% 6% 10% 19% 10% 1	1330
	11th to 20th	Night	54% 8% 11% 14% 12% 1	1330
	21st to end	Night	56% 8% 10% 16% 11%	1330
July	1st to 10th	Night	44% 9% 18% 24% 5%	2175
	11th to 20th	Night	44% 7% 18% 22% 9%	2168
	21st to end	Night	41% 8% 19% 23% 8%	2439
August	1st to 10th	Night	47% 9% 21% 20% 3	2496
	11th to 20th	Night	60% 7% 17% 14% 2	2800
	21st to end	Night	41% 7% 15% 30% 7%	3124
September	1st to 10th	Night	50% 8% 15% 22% 5%	1841
	11th to 20th	Night	54% 5% 16% 19% 6%	2090
	21st to end	Night	51% 6% 13% 24% 5%	2090
October	1st to 10th	Night	58% 4 12% 22% 4 1	3660
	11th to 20th	Night	66% 4 14% 14% 2	3988
	21st to end	Night	67% 6% 10% 15% 2 1	4467
November	1st to 10th	Night	70% 5% 12% 10% 2	2659
	11th to 20th	Night	70% 5% 14% 10% 2	2840
	21st to end	Night	77% 4 11% 7% 2	3000
December	1st to 10th	Night	69% 6% 11% 11% 2	4910
	11th to 20th	Night	68% 4 12% 13% 4	5592
	21st to end	Night	62% 7% 9% 17% 5% 1	7502

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% 19% 36% 23% 8% 1	200
	11th to 20th	Day	21% 15% 36% 17% 9% 4	200
	21st to end	Day	15% 21% 30% 24% 9% 2	220
February	1st to 10th	Day	14% 20% 40% 15% 8% 2	210
	11th to 20th	Day	14% 23% 36% 21% 5% 1	396
	21st to end	Day	20% 18% 40% 15% 5% 2	399
March	1st to 10th	Day	20% 21% 31% 21% 6% 2	500
	11th to 20th	Day	21% 19% 34% 18% 6% 1	500
	21st to end	Day	26% 22% 30% 14% 6% 1	550
April	1st to 10th	Day	29% 20% 33% 13% 4 1	500
	11th to 20th	Day	26% 19% 30% 16% 6% 3	492
	21st to end	Day	31% 20% 27% 13% 6% 2	500
May	1st to 10th	Day	33% 16% 23% 19% 7% 1	538
	11th to 20th	Day	27% 18% 25% 19% 9% 2	724
	21st to end	Day	33% 20% 24% 17% 5%	760
June	1st to 10th	Day	29% 15% 24% 23% 7% 1	680
	11th to 20th	Day	26% 17% 28% 19% 9% 1	680
	21st to end	Day	31% 16% 25% 20% 6% 2	680
July	1st to 10th	Day	24% 13% 28% 23% 10% 2	670
	11th to 20th	Day	24% 13% 29% 24% 8% 2	668
	21st to end	Day	22% 11% 30% 25% 10% 3	664
August	1st to 10th	Day	26% 11% 32% 18% 9% 3	486
	11th to 20th	Day	24% 11% 28% 24% 11% 2	479
	21st to end	Day	26% 14% 28% 18% 10% 5%	539
September	1st to 10th	Day	27% 19% 31% 15% 5% 3	490
	11th to 20th	Day	34% 15% 27% 13% 8% 3	490
	21st to end	Day	27% 20% 28% 17% 6% 2	490
October	1st to 10th	Day	28% 20% 29% 14% 7% 2	435
	11th to 20th	Day	42% 13% 23% 13% 6% 3	390
	21st to end	Day	34% 18% 24% 14% 8% 1	429
November	1st to 10th	Day	34% 25% 27% 10% 4 1	395
	11th to 20th	Day	32% 14% 30% 15% 6% 2	359
	21st to end	Day	26% 24% 36% 8% 6%	200
December	1st to 10th	Day	17% 17% 28% 24% 11% 5%	200
	11th to 20th	Day	24% 25% 32% 15% 5% 1	200
	21st to end	Day	23% 20% 32% 14% 11%	220
January	1st to 10th	Night	18% 16% 35% 23% 8%	900
	11th to 20th	Night	21% 16% 31% 22% 8%	880
	21st to end	Night	13% 14% 37% 27% 8% 1	880
February	1st to 10th	Night	11% 16% 41% 21% 10% 1	800
	11th to 20th	Night	19% 16% 35% 22% 7%	783
	21st to end	Night	15% 15% 35% 23% 9% 2	660
March	1st to 10th	Night	16% 17% 36% 24% 7% 1	800
	11th to 20th	Night	20% 18% 32% 22% 7% 1	800
	21st to end	Night	22% 19% 32% 21% 6%	880
April	1st to 10th	Night	27% 16% 34% 19% 5%	743
	11th to 20th	Night	23% 18% 31% 18% 8% 1	594
	21st to end	Night	30% 13% 29% 20% 8% 1	600
May	1st to 10th	Night	30% 11% 29% 22% 7% 1	538
	11th to 20th	Night	26% 11% 32% 22% 8% 1	394
	21st to end	Night	25% 15% 36% 21% 2	423
June	1st to 10th	Night	24% 14% 30% 25% 7%	380
	11th to 20th	Night	24% 10% 34% 24% 8% 1	380
	21st to end	Night	28% 11% 27% 26% 7% 1	380
July	1st to 10th	Night	19% 9% 33% 30% 8% 1	370
	11th to 20th	Night	20% 10% 27% 30% 13% 1	368
	21st to end	Night	22% 9% 25% 31% 12% 1	416
August	1st to 10th	Night	24% 7% 26% 28% 15% 1	378
	11th to 20th	Night	27% 9% 25% 26% 12%	553
	21st to end	Night	25% 10% 27% 26% 11% 2	627
September	1st to 10th	Night	27% 13% 31% 22% 6%	658
	11th to 20th	Night	30% 15% 25% 22% 8% 1	760
	21st to end	Night	27% 16% 29% 21% 7% 1	760
October	1st to 10th	Night	29% 18% 29% 18% 6% 1	760
	11th to 20th	Night	33% 13% 24% 21% 7% 1	760
	21st to end	Night	36% 14% 26% 18% 7%	836
November	1st to 10th	Night	32% 19% 29% 15% 5%	842
	11th to 20th	Night	28% 17% 29% 17% 7% 1	900
	21st to end	Night	29% 17% 30% 18% 5%	900
December	1st to 10th	Night	25% 14% 30% 22% 7% 2	900
	11th to 20th	Night	23% 16% 34% 21% 5%	900
	21st to end	Night	22% 16% 30% 22% 8% 2	990

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