Minto-Brown Island Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Minto-Brown Island Park clear sky chart from 2005-11-06 to 2024-11-02.

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% 8% 3 8% 5% 4 4 3 5% 6% 38%	101512
	Night	18% 9% 3 8% 5% 4 4 3 4 5% 37%	97598
Transparency	Day	46% 7% 12% 17% 13% 5%	101257
	Night	48% 8% 12% 17% 11% 4	97443
Seeing	Day	19% 10% 21% 27% 18% 5%	14696
	Night	21% 7% 19% 32% 19% 2	23614

By Month

Percentage Cloud Cover SW (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	32% 17% 7% 14% 6% 5% 4 3 3 3 7%	2539
	11th to 20th	Day	38% 13% 4 11% 6% 4 4 3 3 3 12%	2540
	21st to end	Day	27% 13% 5% 13% 7% 5% 5% 4 4 4 13%	3119
February	1st to 10th	Day	27% 11% 4 11% 7% 6% 5% 4 5% 6% 14%	1710
	11th to 20th	Day	26% 14% 4 11% 7% 5% 4 3 4 5% 16%	1665
	21st to end	Day	26% 14% 4 10% 6% 5% 4 4 4 5% 17%	1480
March	1st to 10th	Day	17% 12% 5% 12% 8% 7% 6% 5% 6% 5% 16%	3324
	11th to 20th	Day	16% 10% 3 8% 6% 4 4 4 5% 5% 34%	3490
	21st to end	Day	21% 12% 5% 11% 6% 6% 6% 4 6% 5% 17%	3880
April	1st to 10th	Day	24% 12% 4 10% 7% 6% 5% 3 5% 6% 18%	2280
	11th to 20th	Day	20% 11% 4 9% 5% 5% 4 4 5% 6% 26%	2249
	21st to end	Day	19% 10% 3 8% 6% 5% 5% 4 5% 8% 27%	2470
May	1st to 10th	Day	19% 8% 3 8% 5% 5% 4 3 6% 5% 34%	4296
	11th to 20th	Day	10% 5% 2 5% 4 4 3 3 5% 6% 53%	4377
	21st to end	Day	15% 7% 3 8% 7% 6% 6% 5% 7% 7% 28%	4813
June	1st to 10th	Day	18% 10% 3 7% 5% 4 4 4 5% 6% 34%	2660
	11th to 20th	Day	15% 8% 3 8% 6% 5% 5% 5% 6% 8% 32%	2660
	21st to end	Day	8% 5% 2 5% 4 4 4 4 4 6% 55%	2660
July	1st to 10th	Day	3 2 1 3 2 2 3 2 3 5% 74%	4420
	11th to 20th	Day	4 2 1 2 2 2 2 2 3 4 76%	4420
	21st to end	Day	4 2 1 2 1 2 2 2 3 4 77%	4747
August	1st to 10th	Day	2 2 1 3 3 3 3 3 4 6% 70%	4091
	11th to 20th	Day	4 4 2 5% 4 3 4 4 6% 8% 57%	4026
	21st to end	Day	6% 6% 1 5% 3 4 4 3 5% 7% 56%	4309
September	1st to 10th	Day	6% 3 1 4 3 3 3 2 5% 7% 64%	2280
	11th to 20th	Day	9% 7% 3 8% 4 4 5% 3 6% 6% 44%	2263
	21st to end	Day	14% 5% 2 7% 4 3 5% 3 4 6% 46%	2008
October	1st to 10th	Day	15% 7% 3 7% 5% 4 4 4 5% 6% 39%	1900
	11th to 20th	Day	16% 9% 4 10% 6% 5% 5% 3 4 7% 29%	1900
	21st to end	Day	20% 13% 4 10% 6% 5% 3 3 5% 5% 26%	2075
November	1st to 10th	Day	25% 14% 6% 12% 6% 5% 5% 4 4 5% 15%	1579
	11th to 20th	Day	27% 13% 4 11% 8% 4 4 3 4 5% 17%	1520
	21st to end	Day	24% 12% 3 13% 6% 4 4 4 5% 5% 20%	1520
December	1st to 10th	Day	25% 12% 7% 10% 6% 4 4 3 4 5% 21%	1520
	11th to 20th	Day	26% 11% 5% 13% 8% 6% 6% 5% 6% 5% 9%	1928
	21st to end	Day	30% 15% 5% 18% 7% 5% 5% 3 3 3 6%	2794
January	1st to 10th	Night	30% 18% 7% 11% 6% 4 4 3 4 3 10%	4406
	11th to 20th	Night	36% 16% 4 8% 4 4 3 2 4 4 15%	4420
	21st to end	Night	32% 13% 5% 12% 5% 5% 4 3 4 4 14%	4543
February	1st to 10th	Night	23% 13% 5% 10% 7% 6% 5% 3 4 6% 17%	2470
	11th to 20th	Night	24% 12% 4 9% 6% 5% 4 2 5% 4 24%	2402
	21st to end	Night	24% 14% 3 9% 6% 5% 5% 4 4 6% 21%	1973
March	1st to 10th	Night	14% 13% 5% 11% 6% 8% 6% 4 6% 5% 20%	3535
	11th to 20th	Night	14% 8% 3 7% 5% 5% 5% 4 6% 6% 39%	3490
	21st to end	Night	19% 13% 4 12% 7% 7% 5% 4 5% 5% 18%	3772
April	1st to 10th	Night	24% 11% 3 9% 6% 5% 3 4 5% 6% 24%	1900
	11th to 20th	Night	18% 11% 2 8% 4 5% 4 3 6% 7% 33%	1876
	21st to end	Night	18% 9% 3 8% 5% 4 5% 4 6% 7% 32%	1710
May	1st to 10th	Night	19% 7% 3 7% 5% 4 4 3 4 5% 39%	2668
	11th to 20th	Night	8% 6% 2 4 3 3 3 3 4 5% 58%	2516
	21st to end	Night	12% 7% 2 6% 4 4 5% 4 8% 8% 39%	2762
June	1st to 10th	Night	16% 6% 4 7% 5% 4 5% 3 4 7% 39%	1520
	11th to 20th	Night	12% 7% 3 6% 4 4 4 3 5% 7% 44%	1520
	21st to end	Night	6% 5% 2 4 4 3 3 3 4 6% 61%	1520
July	1st to 10th	Night	2 2 1 2 2 1 1 2 2 4 82%	2540
	11th to 20th	Night	3 3 1 2 1 1 2 2 2 4 79%	2540
	21st to end	Night	2 2 1 2 1 1 2 1 3 4 82%	2790
August	1st to 10th	Night	1 2 1 2 2 1 2 2 4 5% 77%	2848
	11th to 20th	Night	5% 4 1 4 3 4 4 3 5% 6% 62%	2812
	21st to end	Night	8% 4 2 4 2 2 2 2 3 5% 65%	3363
September	1st to 10th	Night	5% 3 1 3 2 2 2 2 5% 5% 69%	1900
	11th to 20th	Night	8% 5% 3 6% 4 5% 5% 3 4 6% 52%	1914
	21st to end	Night	9% 5% 2 6% 4 3 4 2 5% 8% 53%	2171
October	1st to 10th	Night	13% 7% 2 7% 4 4 3 4 4 6% 46%	2280
	11th to 20th	Night	16% 6% 2 6% 5% 4 5% 4 6% 7% 40%	2280
	21st to end	Night	20% 9% 3 8% 4 4 3 3 4 5% 36%	2522
November	1st to 10th	Night	25% 9% 3 8% 5% 5% 5% 4 6% 7% 23%	2517
	11th to 20th	Night	28% 12% 3 9% 5% 4 4 3 5% 5% 22%	2660
	21st to end	Night	21% 11% 3 10% 6% 5% 5% 3 5% 5% 26%	2660
December	1st to 10th	Night	25% 10% 3 9% 6% 5% 4 3 5% 5% 24%	2660
	11th to 20th	Night	26% 12% 4 11% 7% 6% 5% 4 5% 6% 15%	3276
	21st to end	Night	24% 14% 6% 14% 7% 6% 5% 4 5% 4 12%	4862

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	83% 8% 4 3 1 1	2539
	11th to 20th	Day	77% 5% 6% 8% 3 1	2540
	21st to end	Day	72% 9% 7% 7% 4	3119
February	1st to 10th	Day	70% 7% 9% 9% 4	1710
	11th to 20th	Day	69% 8% 9% 9% 4 1	1674
	21st to end	Day	70% 7% 9% 8% 5% 2	1480
March	1st to 10th	Day	63% 9% 13% 13% 3	3324
	11th to 20th	Day	49% 8% 9% 23% 10% 1	3490
	21st to end	Day	66% 11% 12% 7% 4	3880
April	1st to 10th	Day	66% 8% 11% 11% 3	2280
	11th to 20th	Day	59% 8% 11% 12% 7% 3	2252
	21st to end	Day	56% 9% 13% 13% 7% 1	2470
May	1st to 10th	Day	48% 9% 13% 18% 12%	4296
	11th to 20th	Day	30% 6% 18% 32% 13% 1	4380
	21st to end	Day	46% 16% 20% 15% 2	4814
June	1st to 10th	Day	51% 7% 16% 20% 6% 1	2660
	11th to 20th	Day	48% 10% 19% 17% 6%	2660
	21st to end	Day	30% 7% 18% 30% 13% 4	2660
July	1st to 10th	Day	14% 3 9% 19% 23% 32%	4351
	11th to 20th	Day	14% 3 6% 18% 37% 21%	4345
	21st to end	Day	13% 3 11% 28% 39% 7%	4597
August	1st to 10th	Day	16% 4 9% 30% 28% 12%	4076
	11th to 20th	Day	25% 5% 18% 32% 16% 4	4065
	21st to end	Day	27% 5% 13% 25% 24% 6%	4308
September	1st to 10th	Day	20% 4 13% 30% 21% 12%	2280
	11th to 20th	Day	38% 7% 13% 20% 15% 6%	2263
	21st to end	Day	38% 7% 13% 21% 15% 5%	2008
October	1st to 10th	Day	43% 7% 11% 19% 17% 4	1900
	11th to 20th	Day	54% 7% 12% 14% 12% 2	1900
	21st to end	Day	59% 7% 8% 13% 13% 1	2075
November	1st to 10th	Day	70% 7% 9% 9% 4	1579
	11th to 20th	Day	70% 6% 9% 8% 5% 2	1520
	21st to end	Day	66% 7% 7% 8% 11% 1	1520
December	1st to 10th	Day	66% 5% 9% 10% 9% 1	1520
	11th to 20th	Day	70% 13% 7% 8% 1	1928
	21st to end	Day	81% 8% 6% 2 2	2794
January	1st to 10th	Night	78% 8% 6% 4 3 1	4406
	11th to 20th	Night	73% 7% 5% 10% 4 1	4420
	21st to end	Night	73% 7% 7% 8% 5% 1	4543
February	1st to 10th	Night	67% 8% 9% 11% 4 1	2470
	11th to 20th	Night	61% 7% 12% 11% 6% 2	2404
	21st to end	Night	63% 7% 11% 11% 6% 2	1973
March	1st to 10th	Night	60% 10% 12% 13% 4	3535
	11th to 20th	Night	42% 10% 14% 22% 12% 1	3490
	21st to end	Night	64% 12% 12% 11% 1	3772
April	1st to 10th	Night	60% 9% 14% 12% 5%	1900
	11th to 20th	Night	50% 9% 16% 15% 7% 3	1876
	21st to end	Night	51% 9% 14% 17% 7% 2	1710
May	1st to 10th	Night	43% 12% 12% 22% 10% 1	2668
	11th to 20th	Night	27% 6% 16% 36% 12% 2	2516
	21st to end	Night	36% 17% 29% 15% 3	2762
June	1st to 10th	Night	44% 8% 16% 26% 5% 1	1520
	11th to 20th	Night	38% 11% 18% 25% 8%	1520
	21st to end	Night	25% 7% 18% 34% 13% 4	1520
July	1st to 10th	Night	11% 3 8% 20% 27% 31%	2500
	11th to 20th	Night	13% 3 7% 19% 32% 27%	2492
	21st to end	Night	9% 2 12% 31% 39% 8%	2703
August	1st to 10th	Night	11% 3 9% 37% 31% 9%	2839
	11th to 20th	Night	23% 4 22% 34% 12% 4	2839
	21st to end	Night	23% 4 14% 30% 22% 7%	3363
September	1st to 10th	Night	17% 5% 13% 31% 22% 11%	1900
	11th to 20th	Night	32% 7% 15% 24% 14% 9%	1914
	21st to end	Night	30% 6% 16% 23% 17% 8%	2171
October	1st to 10th	Night	38% 7% 10% 24% 18% 4	2280
	11th to 20th	Night	41% 8% 14% 18% 15% 4	2280
	21st to end	Night	49% 8% 10% 15% 16% 2	2522
November	1st to 10th	Night	59% 9% 10% 15% 6%	2517
	11th to 20th	Night	64% 7% 10% 9% 8% 2	2660
	21st to end	Night	58% 8% 8% 11% 12% 3	2660
December	1st to 10th	Night	60% 7% 10% 12% 10% 1	2660
	11th to 20th	Night	68% 11% 8% 9% 4	3276
	21st to end	Night	70% 13% 7% 6% 2	4862

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	39% 17% 18% 17% 7% 2	180
	11th to 20th	Day	35% 11% 21% 19% 11% 3	180
	21st to end	Day	28% 12% 21% 21% 13% 4	393
February	1st to 10th	Day	33% 11% 20% 19% 13% 4	370
	11th to 20th	Day	33% 12% 26% 16% 10% 3	365
	21st to end	Day	31% 17% 21% 19% 11% 2	340
March	1st to 10th	Day	30% 13% 25% 21% 10% 1	460
	11th to 20th	Day	27% 14% 20% 22% 14% 3	460
	21st to end	Day	28% 16% 26% 20% 9% 1	506
April	1st to 10th	Day	30% 15% 21% 19% 11% 4	460
	11th to 20th	Day	25% 17% 26% 19% 9% 4	452
	21st to end	Day	23% 15% 25% 20% 15% 2	460
May	1st to 10th	Day	18% 13% 23% 26% 14% 5%	463
	11th to 20th	Day	23% 10% 18% 25% 18% 6%	488
	21st to end	Day	15% 9% 21% 28% 21% 7%	529
June	1st to 10th	Day	18% 10% 21% 27% 21% 3	490
	11th to 20th	Day	16% 9% 25% 33% 14% 2	490
	21st to end	Day	6% 7% 20% 37% 26% 5%	490
July	1st to 10th	Day	5% 5% 19% 39% 24% 8%	486
	11th to 20th	Day	4 3 22% 38% 25% 7%	484
	21st to end	Day	3 2 17% 38% 34% 6%	531
August	1st to 10th	Day	3 2 15% 38% 31% 10%	487
	11th to 20th	Day	3 4 11% 40% 31% 11%	477
	21st to end	Day	4 5% 22% 35% 27% 7%	539
September	1st to 10th	Day	7% 4 23% 32% 27% 7%	490
	11th to 20th	Day	12% 7% 19% 30% 25% 7%	490
	21st to end	Day	14% 9% 22% 30% 19% 5%	490
October	1st to 10th	Day	17% 9% 22% 26% 20% 7%	490
	11th to 20th	Day	20% 8% 17% 27% 21% 6%	490
	21st to end	Day	25% 13% 25% 20% 12% 5%	524
November	1st to 10th	Day	31% 14% 25% 18% 10% 3	224
	11th to 20th	Day	26% 13% 23% 16% 17% 6%	180
	21st to end	Day	28% 15% 17% 19% 16% 4	180
December	1st to 10th	Day	33% 11% 18% 20% 13% 4	180
	11th to 20th	Day	39% 11% 23% 17% 8% 2	180
	21st to end	Day	35% 14% 18% 19% 12% 2	198
January	1st to 10th	Night	35% 12% 18% 20% 12% 2	760
	11th to 20th	Night	35% 9% 16% 20% 18% 2	760
	21st to end	Night	28% 8% 16% 29% 17% 3	836
February	1st to 10th	Night	27% 11% 19% 25% 17% 2	760
	11th to 20th	Night	29% 10% 20% 25% 15%	744
	21st to end	Night	29% 13% 19% 26% 13%	628
March	1st to 10th	Night	25% 11% 22% 28% 13% 1	760
	11th to 20th	Night	23% 11% 20% 29% 16% 1	760
	21st to end	Night	26% 11% 23% 26% 13% 1	836
April	1st to 10th	Night	29% 8% 19% 26% 18% 1	760
	11th to 20th	Night	20% 11% 23% 29% 16% 1	748
	21st to end	Night	20% 9% 21% 32% 17% 1	570
May	1st to 10th	Night	14% 6% 26% 36% 16% 1	456
	11th to 20th	Night	16% 6% 20% 36% 22% 2	374
	21st to end	Night	17% 6% 20% 36% 20% 1	411
June	1st to 10th	Night	18% 5% 18% 41% 18%	380
	11th to 20th	Night	12% 7% 26% 44% 11% 1	380
	21st to end	Night	8% 2 26% 48% 16%	380
July	1st to 10th	Night	4 3 14% 55% 24%	370
	11th to 20th	Night	4 3 23% 51% 18% 1	368
	21st to end	Night	3 2 16% 55% 23% 1	433
August	1st to 10th	Night	3 1 11% 46% 34% 4	567
	11th to 20th	Night	6% 1 8% 46% 37% 2	564
	21st to end	Night	6% 3 19% 44% 27% 2	753
September	1st to 10th	Night	7% 2 18% 45% 26% 1	760
	11th to 20th	Night	9% 3 14% 37% 31% 6%	760
	21st to end	Night	10% 5% 18% 38% 26% 4	760
October	1st to 10th	Night	15% 4 21% 34% 24% 3	760
	11th to 20th	Night	18% 5% 16% 33% 24% 4	760
	21st to end	Night	25% 8% 20% 27% 17% 3	836
November	1st to 10th	Night	28% 9% 17% 31% 15% 1	744
	11th to 20th	Night	31% 9% 19% 25% 14% 1	760
	21st to end	Night	25% 8% 18% 29% 18% 2	760
December	1st to 10th	Night	29% 8% 15% 29% 17% 3	760
	11th to 20th	Night	33% 10% 18% 22% 16% 1	760
	21st to end	Night	35% 12% 18% 22% 11% 1	836

Page generated at 2024-10-29 22:22:55. Version ac07

Copyright © 2024 Attilla Danko.