Maintz Conservation Area
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Maintz Conservation Area clear sky chart from 2005-11-06 to 2026-06-01.

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	11% 7% 2 6% 4 4 4 4 6% 7% 44%	132007
	Night	13% 7% 2 6% 4 4 4 3 5% 7% 45%	131404
Transparency	Day	38% 4 11% 26% 18% 3	135614
	Night	39% 3 10% 25% 19% 4	135875
Seeing	Day	14% 7% 23% 27% 20% 9%	17604
	Night	17% 7% 25% 33% 17% 2	27465

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% 9% 4 8% 4 4 4 3 4 6% 40%	4691
	11th to 20th	Day	9% 6% 3 6% 5% 4 4 3 4 6% 50%	5127
	21st to end	Day	17% 9% 3 6% 4 4 3 2 4 5% 42%	5812
February	1st to 10th	Day	15% 11% 3 7% 4 4 4 3 4 6% 39%	1958
	11th to 20th	Day	16% 10% 3 7% 5% 4 3 3 5% 6% 39%	2048
	21st to end	Day	14% 10% 3 7% 5% 4 4 4 6% 5% 39%	1730
March	1st to 10th	Day	16% 11% 3 6% 4 4 4 3 3 5% 42%	4580
	11th to 20th	Day	9% 6% 2 5% 3 3 3 3 5% 6% 54%	5060
	21st to end	Day	13% 8% 2 8% 4 3 4 4 6% 7% 42%	5954
April	1st to 10th	Day	12% 6% 2 5% 4 4 5% 4 6% 7% 45%	2520
	11th to 20th	Day	14% 8% 3 6% 5% 3 4 3 4 7% 42%	2494
	21st to end	Day	15% 7% 3 6% 5% 4 4 5% 6% 7% 39%	2520
May	1st to 10th	Day	14% 7% 3 8% 5% 6% 6% 5% 7% 9% 30%	5666
	11th to 20th	Day	16% 8% 3 7% 5% 5% 5% 4 6% 8% 35%	6118
	21st to end	Day	15% 6% 2 7% 5% 5% 4 4 5% 7% 41%	7089
June	1st to 10th	Day	9% 4 2 5% 5% 5% 5% 4 6% 9% 45%	2801
	11th to 20th	Day	5% 4 2 5% 4 5% 5% 4 7% 9% 50%	2800
	21st to end	Day	5% 4 1 4 4 5% 5% 4 8% 12% 47%	2800
July	1st to 10th	Day	8% 5% 2 6% 5% 4 5% 4 7% 9% 46%	6360
	11th to 20th	Day	5% 3 2 5% 4 5% 5% 5% 8% 12% 45%	6360
	21st to end	Day	6% 5% 2 7% 5% 5% 6% 6% 8% 10% 40%	6564
August	1st to 10th	Day	4 3 2 4 4 4 4 4 6% 10% 55%	4074
	11th to 20th	Day	11% 5% 2 5% 4 4 4 4 6% 9% 46%	3849
	21st to end	Day	6% 4 2 4 3 3 4 3 6% 9% 56%	4312
September	1st to 10th	Day	10% 5% 2 6% 4 4 4 3 6% 7% 49%	2400
	11th to 20th	Day	9% 6% 2 5% 3 4 4 3 6% 7% 49%	2338
	21st to end	Day	11% 6% 2 4 4 2 3 4 5% 7% 52%	2200
October	1st to 10th	Day	8% 3 2 4 2 3 3 4 4 6% 60%	2063
	11th to 20th	Day	12% 5% 2 5% 3 3 4 3 4 6% 54%	2000
	21st to end	Day	18% 7% 2 5% 3 3 3 3 4 5% 47%	2169
November	1st to 10th	Day	11% 5% 2 5% 4 2 4 3 5% 6% 54%	1852
	11th to 20th	Day	12% 7% 2 6% 4 4 3 4 4 6% 48%	1890
	21st to end	Day	18% 8% 3 5% 3 3 4 3 4 5% 43%	1890
December	1st to 10th	Day	10% 9% 2 6% 4 4 4 3 5% 5% 51%	2760
	11th to 20th	Day	14% 8% 3 7% 5% 4 3 3 4 6% 43%	3088
	21st to end	Day	23% 14% 4 8% 4 4 3 3 4 5% 28%	4070
January	1st to 10th	Night	15% 9% 3 8% 4 4 4 3 5% 5% 40%	8232
	11th to 20th	Night	11% 8% 3 8% 4 4 4 3 5% 5% 45%	7860
	21st to end	Night	17% 8% 3 7% 4 4 4 3 5% 5% 41%	8402
February	1st to 10th	Night	16% 11% 4 7% 5% 4 3 3 4 6% 37%	2660
	11th to 20th	Night	16% 8% 3 7% 5% 3 3 3 3 6% 42%	2458
	21st to end	Night	17% 8% 2 6% 4 3 4 4 5% 5% 42%	2076
March	1st to 10th	Night	16% 9% 3 7% 4 5% 4 3 5% 5% 38%	5493
	11th to 20th	Night	11% 6% 2 6% 4 4 4 4 5% 6% 49%	5150
	21st to end	Night	13% 6% 2 7% 5% 5% 4 3 6% 7% 41%	5215
April	1st to 10th	Night	10% 6% 2 5% 4 3 5% 4 5% 9% 47%	2100
	11th to 20th	Night	14% 5% 2 6% 4 4 5% 4 6% 7% 44%	2075
	21st to end	Night	19% 7% 2 6% 4 4 5% 3 5% 7% 40%	2100
May	1st to 10th	Night	16% 7% 3 7% 5% 5% 5% 4 6% 8% 35%	4449
	11th to 20th	Night	14% 7% 3 8% 5% 4 5% 4 5% 8% 38%	3998
	21st to end	Night	15% 7% 3 7% 5% 5% 4 3 6% 7% 38%	4030
June	1st to 10th	Night	9% 4 2 6% 5% 5% 4 5% 6% 9% 46%	1600
	11th to 20th	Night	5% 3 2 5% 4 4 4 4 6% 10% 54%	1600
	21st to end	Night	4 2 1 4 4 4 4 5% 7% 11% 55%	1600
July	1st to 10th	Night	8% 5% 2 5% 4 4 5% 4 5% 8% 51%	3618
	11th to 20th	Night	6% 4 2 5% 5% 4 5% 5% 5% 10% 49%	3617
	21st to end	Night	6% 5% 2 6% 4 3 4 4 7% 11% 47%	4302
August	1st to 10th	Night	3 2 1 4 3 3 4 4 6% 8% 62%	3080
	11th to 20th	Night	7% 5% 2 5% 4 4 4 4 5% 8% 52%	3200
	21st to end	Night	3 4 2 4 3 3 4 4 5% 8% 61%	3586
September	1st to 10th	Night	10% 5% 2 5% 4 4 3 3 4 6% 53%	2000
	11th to 20th	Night	8% 5% 2 4 4 4 3 4 5% 7% 53%	2040
	21st to end	Night	11% 4 1 4 4 4 3 3 5% 6% 54%	2200
October	1st to 10th	Night	6% 4 1 4 3 3 3 3 4 6% 63%	2333
	11th to 20th	Night	11% 5% 2 5% 3 3 3 2 4 4 57%	2400
	21st to end	Night	18% 7% 2 5% 3 3 3 2 4 5% 49%	2670
November	1st to 10th	Night	10% 5% 2 4 3 2 2 2 5% 6% 57%	2666
	11th to 20th	Night	12% 6% 2 5% 4 3 3 2 3 7% 53%	2730
	21st to end	Night	18% 7% 3 5% 4 3 2 2 4 5% 47%	2730
December	1st to 10th	Night	15% 8% 2 6% 3 3 3 3 4 5% 47%	4645
	11th to 20th	Night	15% 7% 2 6% 4 4 4 3 4 6% 45%	5339
	21st to end	Night	23% 12% 3 7% 4 4 4 3 4 5% 32%	7150

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	46% 3 12% 26% 10% 2	4692
	11th to 20th	Day	36% 3 7% 30% 20% 4	5127
	21st to end	Day	46% 2 9% 21% 13% 8%	5812
February	1st to 10th	Day	48% 2 12% 23% 14% 1	1958
	11th to 20th	Day	47% 3 10% 20% 14% 5%	2058
	21st to end	Day	47% 4 8% 23% 13% 5%	1730
March	1st to 10th	Day	48% 2 4 22% 18% 6%	4580
	11th to 20th	Day	33% 3 9% 29% 21% 6%	5060
	21st to end	Day	42% 3 13% 29% 12% 1	5956
April	1st to 10th	Day	38% 4 12% 27% 19% 2	2520
	11th to 20th	Day	44% 2 11% 22% 16% 4	2494
	21st to end	Day	45% 3 11% 26% 14% 1	2520
May	1st to 10th	Day	49% 5% 12% 22% 11% 1	5701
	11th to 20th	Day	47% 4 12% 23% 12% 1	6122
	21st to end	Day	43% 4 9% 23% 18% 3	7103
June	1st to 10th	Day	34% 4 14% 26% 19% 2	2801
	11th to 20th	Day	30% 5% 10% 30% 22% 3	2800
	21st to end	Day	28% 5% 17% 27% 18% 5%	2800
July	1st to 10th	Day	34% 5% 11% 27% 19% 3	6291
	11th to 20th	Day	30% 8% 18% 32% 12% 1	6285
	21st to end	Day	35% 8% 17% 30% 9% 1	6378
August	1st to 10th	Day	24% 5% 14% 33% 22% 1	4060
	11th to 20th	Day	35% 4 13% 28% 17% 2	3885
	21st to end	Day	25% 4 12% 37% 18% 3	4311
September	1st to 10th	Day	35% 4 9% 28% 19% 5%	2400
	11th to 20th	Day	34% 4 10% 25% 26% 2	2338
	21st to end	Day	32% 4 7% 27% 27% 3	2200
October	1st to 10th	Day	16% 2 6% 21% 45% 11%	3362
	11th to 20th	Day	23% 2 6% 23% 36% 10%	3240
	21st to end	Day	32% 3 5% 28% 28% 5%	3483
November	1st to 10th	Day	33% 4 9% 29% 20% 6%	1852
	11th to 20th	Day	39% 2 7% 25% 22% 6%	1890
	21st to end	Day	44% 2 7% 26% 19% 2	1890
December	1st to 10th	Day	36% 2 8% 36% 16% 1	2760
	11th to 20th	Day	45% 3 8% 27% 16% 2	3085
	21st to end	Day	61% 2 11% 16% 8% 2	4070
January	1st to 10th	Night	48% 2 12% 27% 11% 1	8233
	11th to 20th	Night	40% 4 6% 26% 22% 4	7860
	21st to end	Night	46% 3 9% 23% 16% 3	8402
February	1st to 10th	Night	50% 2 9% 23% 14% 2	2660
	11th to 20th	Night	44% 3 9% 23% 17% 3	2459
	21st to end	Night	45% 2 8% 23% 17% 4	2076
March	1st to 10th	Night	49% 3 6% 19% 17% 6%	5493
	11th to 20th	Night	37% 3 9% 23% 19% 9%	5150
	21st to end	Night	43% 3 11% 29% 12% 1	5215
April	1st to 10th	Night	34% 4 12% 28% 19% 4	2100
	11th to 20th	Night	39% 4 10% 23% 20% 4	2075
	21st to end	Night	45% 3 8% 26% 15% 3	2100
May	1st to 10th	Night	48% 5% 16% 22% 9% 1	4479
	11th to 20th	Night	46% 4 13% 21% 14% 2	3999
	21st to end	Night	45% 4 10% 23% 15% 3	4038
June	1st to 10th	Night	35% 3 14% 26% 20% 3	1600
	11th to 20th	Night	26% 4 12% 28% 25% 6%	1600
	21st to end	Night	22% 5% 17% 30% 18% 8%	1600
July	1st to 10th	Night	32% 5% 11% 25% 23% 3	3580
	11th to 20th	Night	32% 7% 15% 31% 13% 3	3572
	21st to end	Night	29% 6% 22% 28% 14% 1	4177
August	1st to 10th	Night	20% 4 19% 36% 21% 1	3070
	11th to 20th	Night	31% 4 16% 27% 18% 4	3230
	21st to end	Night	22% 4 10% 38% 23% 3	3586
September	1st to 10th	Night	33% 4 7% 30% 20% 7%	2000
	11th to 20th	Night	30% 4 9% 28% 25% 4	2040
	21st to end	Night	31% 4 9% 21% 28% 6%	2200
October	1st to 10th	Night	15% 1 6% 18% 44% 16%	3814
	11th to 20th	Night	23% 2 5% 20% 41% 9%	3899
	21st to end	Night	31% 2 6% 25% 28% 7%	4306
November	1st to 10th	Night	30% 3 9% 28% 24% 6%	2666
	11th to 20th	Night	34% 2 7% 26% 23% 7%	2730
	21st to end	Night	42% 2 7% 26% 21% 2	2730
December	1st to 10th	Night	40% 3 9% 29% 18% 1	4645
	11th to 20th	Night	42% 3 11% 23% 20% 1	5341
	21st to end	Night	56% 3 10% 19% 10% 1	7150

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	24% 11% 32% 26% 6% 1	330
	11th to 20th	Day	21% 15% 42% 18% 3 1	330
	21st to end	Day	18% 13% 42% 23% 4	363
February	1st to 10th	Day	22% 9% 42% 19% 6%	330
	11th to 20th	Day	24% 19% 35% 17% 4	330
	21st to end	Day	25% 14% 38% 16% 5% 1	273
March	1st to 10th	Day	19% 15% 37% 21% 8%	330
	11th to 20th	Day	23% 14% 41% 16% 5% 1	330
	21st to end	Day	22% 11% 36% 23% 8%	527
April	1st to 10th	Day	17% 12% 35% 26% 10% 1	540
	11th to 20th	Day	20% 17% 29% 21% 13% 1	532
	21st to end	Day	18% 10% 29% 29% 11% 2	540
May	1st to 10th	Day	15% 10% 32% 27% 12% 3	543
	11th to 20th	Day	18% 6% 27% 24% 16% 9%	616
	21st to end	Day	13% 5% 22% 33% 19% 8%	844
June	1st to 10th	Day	13% 3 17% 24% 27% 16%	731
	11th to 20th	Day	6% 2 15% 36% 28% 13%	730
	21st to end	Day	5% 2 20% 36% 26% 11%	730
July	1st to 10th	Day	10% 2 9% 27% 27% 24%	721
	11th to 20th	Day	7% 1 10% 33% 33% 16%	718
	21st to end	Day	7% 3 10% 29% 35% 16%	794
August	1st to 10th	Day	8% 1 9% 30% 34% 17%	631
	11th to 20th	Day	15% 2 10% 25% 33% 16%	519
	21st to end	Day	9% 1 6% 24% 39% 20%	583
September	1st to 10th	Day	11% 2 9% 29% 33% 17%	530
	11th to 20th	Day	8% 2 8% 25% 37% 19%	530
	21st to end	Day	14% 6% 14% 29% 25% 12%	530
October	1st to 10th	Day	8% 3 17% 38% 23% 10%	393
	11th to 20th	Day	14% 10% 30% 25% 16% 4	330
	21st to end	Day	24% 12% 29% 25% 10% 1	363
November	1st to 10th	Day	14% 11% 28% 32% 11% 5%	330
	11th to 20th	Day	12% 13% 37% 23% 14% 1	330
	21st to end	Day	24% 12% 30% 23% 10% 1	330
December	1st to 10th	Day	15% 13% 35% 25% 9% 3	330
	11th to 20th	Day	21% 12% 35% 23% 8%	330
	21st to end	Day	23% 12% 39% 19% 6%	363
January	1st to 10th	Night	22% 11% 33% 29% 4	1050
	11th to 20th	Night	22% 13% 40% 22% 3	1050
	21st to end	Night	19% 10% 40% 29% 2	1155
February	1st to 10th	Night	22% 13% 35% 27% 3	980
	11th to 20th	Night	22% 15% 34% 26% 3	823
	21st to end	Night	23% 12% 39% 24% 3	692
March	1st to 10th	Night	23% 12% 34% 26% 5%	840
	11th to 20th	Night	22% 9% 33% 30% 6%	664
	21st to end	Night	22% 8% 32% 30% 8%	693
April	1st to 10th	Night	13% 10% 38% 32% 7%	630
	11th to 20th	Night	17% 10% 30% 31% 11% 1	623
	21st to end	Night	22% 4 31% 32% 11% 1	630
May	1st to 10th	Night	17% 3 28% 40% 11% 2	630
	11th to 20th	Night	16% 3 23% 38% 19% 1	621
	21st to end	Night	11% 3 16% 43% 24% 4	683
June	1st to 10th	Night	12% 3 12% 39% 31% 3	600
	11th to 20th	Night	6% 1 9% 49% 33% 2	600
	21st to end	Night	5% 1 13% 43% 36% 2	600
July	1st to 10th	Night	9% 1 7% 33% 41% 10%	585
	11th to 20th	Night	6% 2 8% 36% 42% 7%	582
	21st to end	Night	8% 1 7% 34% 44% 6%	657
August	1st to 10th	Night	6% 1 5% 40% 41% 6%	597
	11th to 20th	Night	9% 1 7% 37% 41% 5%	594
	21st to end	Night	7% 1 6% 34% 45% 7%	660
September	1st to 10th	Night	11% 3 8% 36% 36% 6%	600
	11th to 20th	Night	10% 1 10% 33% 38% 7%	640
	21st to end	Night	13% 2 14% 37% 29% 5%	800
October	1st to 10th	Night	8% 2 18% 40% 28% 4	800
	11th to 20th	Night	15% 5% 27% 33% 20% 1	800
	21st to end	Night	23% 5% 27% 33% 11%	880
November	1st to 10th	Night	14% 5% 30% 37% 13% 1	820
	11th to 20th	Night	17% 6% 33% 33% 11%	840
	21st to end	Night	22% 8% 30% 30% 10%	840
December	1st to 10th	Night	22% 10% 31% 31% 6%	1001
	11th to 20th	Night	22% 8% 31% 32% 6%	1050
	21st to end	Night	26% 10% 32% 28% 4	1155

Page generated at 2026-05-29 00:53:31. Version ac07

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