Black Creek Pond
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Black Creek Pond clear sky chart from 2005-11-06 to 2024-10-20.

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% 10% 4 8% 5% 5% 4 4 5% 7% 32%	101442
	Night	16% 11% 4 9% 5% 5% 4 3 5% 6% 32%	97251
Transparency	Day	50% 7% 12% 20% 10% 1	101200
	Night	51% 8% 12% 19% 9% 1	97113
Seeing	Day	22% 18% 31% 19% 8% 2	14408
	Night	22% 15% 31% 23% 8% 1	23524

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	14% 17% 5% 12% 8% 6% 4 3 5% 5% 21%	2517
	11th to 20th	Day	12% 16% 8% 13% 7% 6% 5% 3 4 4 22%	2520
	21st to end	Day	16% 21% 7% 14% 6% 5% 4 3 3 4 16%	2973
February	1st to 10th	Day	13% 16% 5% 12% 7% 6% 4 4 4 5% 23%	1710
	11th to 20th	Day	11% 16% 5% 11% 7% 5% 5% 4 4 5% 29%	1663
	21st to end	Day	17% 15% 3 9% 6% 6% 5% 4 5% 4 25%	1542
March	1st to 10th	Day	18% 16% 5% 11% 5% 4 4 2 4 5% 27%	3200
	11th to 20th	Day	10% 16% 5% 11% 7% 5% 5% 3 4 5% 29%	3480
	21st to end	Day	11% 10% 4 9% 4 3 4 3 4 6% 42%	3969
April	1st to 10th	Day	21% 13% 3 6% 4 4 4 3 5% 5% 31%	2280
	11th to 20th	Day	22% 10% 3 6% 4 4 3 3 4 4 37%	2254
	21st to end	Day	21% 11% 4 7% 5% 4 4 3 4 4 32%	2406
May	1st to 10th	Day	20% 9% 3 7% 5% 5% 5% 3 6% 6% 33%	4426
	11th to 20th	Day	16% 9% 4 9% 5% 4 4 3 5% 8% 32%	4398
	21st to end	Day	14% 7% 2 7% 5% 5% 5% 4 6% 7% 39%	4837
June	1st to 10th	Day	20% 9% 4 7% 6% 4 5% 4 5% 7% 30%	2660
	11th to 20th	Day	15% 6% 2 7% 5% 5% 5% 4 6% 8% 37%	2660
	21st to end	Day	17% 7% 3 7% 6% 5% 5% 4 5% 7% 33%	2660
July	1st to 10th	Day	11% 7% 3 8% 6% 6% 5% 5% 7% 10% 34%	4440
	11th to 20th	Day	12% 5% 2 6% 4 5% 5% 5% 7% 9% 39%	4440
	21st to end	Day	10% 6% 2 6% 4 5% 5% 4 7% 8% 43%	4814
August	1st to 10th	Day	15% 8% 3 7% 5% 4 5% 4 5% 7% 35%	4245
	11th to 20th	Day	17% 6% 2 7% 4 5% 4 4 6% 8% 36%	4044
	21st to end	Day	13% 6% 2 6% 4 4 5% 4 7% 10% 39%	4183
September	1st to 10th	Day	14% 6% 2 6% 5% 5% 5% 3 6% 7% 40%	2280
	11th to 20th	Day	12% 6% 2 5% 4 4 5% 3 5% 7% 47%	2280
	21st to end	Day	17% 7% 2 7% 5% 5% 3 3 6% 7% 38%	2012
October	1st to 10th	Day	20% 8% 3 7% 4 5% 4 3 5% 6% 34%	1900
	11th to 20th	Day	21% 11% 3 8% 5% 4 4 3 5% 6% 29%	1890
	21st to end	Day	26% 11% 4 8% 5% 5% 5% 3 4 5% 25%	1877
November	1st to 10th	Day	14% 10% 3 8% 6% 5% 4 4 5% 6% 34%	1644
	11th to 20th	Day	17% 14% 4 9% 5% 5% 5% 3 4 6% 28%	1520
	21st to end	Day	19% 16% 6% 10% 6% 6% 4 3 4 6% 20%	1520
December	1st to 10th	Day	20% 20% 6% 11% 7% 4 4 3 5% 4 17%	1520
	11th to 20th	Day	19% 15% 6% 8% 6% 4 4 3 5% 5% 26%	1906
	21st to end	Day	26% 18% 5% 14% 4 3 3 2 3 3 19%	2772
January	1st to 10th	Night	16% 14% 7% 13% 7% 6% 5% 3 5% 6% 19%	4429
	11th to 20th	Night	11% 15% 5% 13% 9% 7% 5% 4 5% 5% 21%	4440
	21st to end	Night	16% 19% 7% 11% 6% 7% 4 3 3 4 19%	4678
February	1st to 10th	Night	13% 17% 6% 12% 6% 5% 4 4 6% 5% 23%	2470
	11th to 20th	Night	13% 13% 6% 11% 6% 5% 4 4 4 6% 29%	2403
	21st to end	Night	13% 13% 4 9% 6% 6% 4 4 6% 5% 29%	1910
March	1st to 10th	Night	18% 14% 4 9% 6% 4 4 2 3 5% 31%	3638
	11th to 20th	Night	14% 16% 5% 10% 5% 4 5% 3 5% 6% 25%	3479
	21st to end	Night	14% 10% 3 7% 5% 4 4 3 5% 6% 39%	3663
April	1st to 10th	Night	20% 10% 3 8% 5% 4 3 3 4 5% 34%	1900
	11th to 20th	Night	19% 9% 3 7% 5% 5% 3 3 4 6% 36%	1875
	21st to end	Night	20% 10% 2 8% 4 4 4 4 4 6% 33%	1791
May	1st to 10th	Night	20% 10% 3 6% 4 5% 5% 3 5% 6% 32%	2514
	11th to 20th	Night	17% 8% 3 6% 4 5% 4 3 6% 7% 36%	2495
	21st to end	Night	13% 7% 3 6% 4 4 6% 4 5% 8% 41%	2738
June	1st to 10th	Night	15% 7% 3 7% 6% 4 5% 5% 6% 8% 35%	1520
	11th to 20th	Night	11% 7% 3 7% 5% 5% 4 4 6% 6% 43%	1520
	21st to end	Night	17% 8% 3 7% 3 5% 5% 3 6% 8% 36%	1520
July	1st to 10th	Night	10% 6% 3 8% 6% 6% 6% 5% 6% 7% 37%	2520
	11th to 20th	Night	12% 5% 2 7% 5% 5% 4 4 5% 8% 44%	2520
	21st to end	Night	10% 5% 2 6% 5% 5% 5% 4 6% 8% 44%	2739
August	1st to 10th	Night	11% 6% 2 7% 4 4 5% 4 6% 8% 42%	2682
	11th to 20th	Night	14% 6% 2 6% 5% 4 4 4 5% 7% 43%	2785
	21st to end	Night	12% 5% 2 6% 4 4 5% 4 6% 9% 43%	3440
September	1st to 10th	Night	12% 5% 3 6% 4 3 4 3 6% 6% 47%	1900
	11th to 20th	Night	14% 5% 2 4 3 4 4 3 5% 6% 51%	1900
	21st to end	Night	17% 7% 2 7% 3 3 3 4 6% 6% 43%	2166
October	1st to 10th	Night	18% 9% 3 6% 4 4 4 4 5% 6% 39%	2280
	11th to 20th	Night	19% 10% 3 9% 5% 5% 4 3 5% 6% 31%	2275
	21st to end	Night	22% 12% 3 8% 5% 4 4 3 5% 7% 27%	2479
November	1st to 10th	Night	17% 12% 3 8% 4 4 4 3 5% 5% 36%	2430
	11th to 20th	Night	17% 12% 3 8% 6% 5% 5% 4 5% 6% 29%	2660
	21st to end	Night	20% 15% 4 10% 5% 4 4 3 5% 6% 24%	2660
December	1st to 10th	Night	18% 19% 5% 11% 6% 5% 5% 4 5% 5% 18%	2660
	11th to 20th	Night	20% 16% 5% 10% 6% 5% 4 3 3 4 26%	3288
	21st to end	Night	28% 18% 5% 13% 5% 4 4 2 3 4 15%	4884

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	60% 13% 11% 9% 6% 1	2518
	11th to 20th	Day	64% 8% 11% 10% 7% 1	2520
	21st to end	Day	71% 6% 7% 9% 5% 1	2973
February	1st to 10th	Day	62% 7% 10% 15% 5% 1	1710
	11th to 20th	Day	57% 6% 11% 15% 9% 1	1672
	21st to end	Day	59% 8% 10% 11% 10% 1	1542
March	1st to 10th	Day	59% 5% 10% 15% 10% 1	3203
	11th to 20th	Day	54% 9% 12% 14% 9% 2	3480
	21st to end	Day	41% 6% 10% 23% 17% 4	3969
April	1st to 10th	Day	54% 5% 9% 17% 12% 3	2280
	11th to 20th	Day	50% 6% 7% 20% 16% 2	2254
	21st to end	Day	54% 6% 8% 14% 14% 3	2406
May	1st to 10th	Day	48% 8% 11% 19% 11% 2	4440
	11th to 20th	Day	46% 10% 13% 19% 10% 1	4402
	21st to end	Day	41% 9% 13% 20% 15% 2	4837
June	1st to 10th	Day	52% 8% 10% 17% 11% 1	2660
	11th to 20th	Day	42% 9% 11% 23% 12% 3	2660
	21st to end	Day	48% 8% 13% 19% 11% 1	2660
July	1st to 10th	Day	44% 6% 15% 24% 11% 1	4370
	11th to 20th	Day	37% 7% 16% 30% 10%	4365
	21st to end	Day	37% 7% 13% 31% 12%	4661
August	1st to 10th	Day	47% 7% 13% 23% 10%	4231
	11th to 20th	Day	43% 8% 14% 25% 8% 1	4083
	21st to end	Day	39% 6% 15% 30% 10% 1	4183
September	1st to 10th	Day	40% 9% 14% 27% 11%	2280
	11th to 20th	Day	35% 8% 14% 28% 15%	2280
	21st to end	Day	45% 7% 13% 25% 10%	2012
October	1st to 10th	Day	50% 5% 12% 21% 10% 1	1900
	11th to 20th	Day	54% 9% 13% 17% 7% 1	1890
	21st to end	Day	61% 7% 11% 15% 6% 1	1877
November	1st to 10th	Day	48% 9% 16% 21% 7% 1	1644
	11th to 20th	Day	57% 7% 12% 14% 9% 1	1520
	21st to end	Day	65% 9% 11% 8% 7% 1	1520
December	1st to 10th	Day	70% 8% 10% 9% 3	1520
	11th to 20th	Day	60% 7% 14% 12% 6%	1906
	21st to end	Day	72% 4 7% 13% 4	2772
January	1st to 10th	Night	64% 10% 12% 11% 3	4429
	11th to 20th	Night	62% 9% 14% 10% 4 1	4440
	21st to end	Night	68% 7% 9% 9% 6% 1	4678
February	1st to 10th	Night	60% 6% 12% 15% 6% 1	2470
	11th to 20th	Night	56% 5% 12% 18% 8% 1	2405
	21st to end	Night	54% 8% 11% 18% 10% 1	1910
March	1st to 10th	Night	55% 6% 10% 19% 8% 1	3648
	11th to 20th	Night	54% 10% 15% 14% 7% 1	3480
	21st to end	Night	41% 8% 10% 22% 14% 4	3663
April	1st to 10th	Night	52% 6% 9% 18% 14% 2	1900
	11th to 20th	Night	50% 5% 8% 20% 15% 1	1875
	21st to end	Night	51% 6% 9% 16% 15% 3	1791
May	1st to 10th	Night	48% 10% 10% 20% 10% 2	2520
	11th to 20th	Night	43% 11% 15% 21% 10% 2	2496
	21st to end	Night	37% 10% 15% 19% 17% 2	2739
June	1st to 10th	Night	44% 10% 14% 20% 11% 1	1520
	11th to 20th	Night	39% 8% 12% 23% 17% 2	1520
	21st to end	Night	45% 11% 13% 18% 13% 1	1520
July	1st to 10th	Night	42% 8% 15% 20% 14% 1	2480
	11th to 20th	Night	38% 5% 13% 34% 10%	2472
	21st to end	Night	37% 8% 15% 26% 14%	2651
August	1st to 10th	Night	39% 8% 14% 26% 12% 1	2672
	11th to 20th	Night	39% 7% 16% 30% 8% 1	2812
	21st to end	Night	37% 7% 16% 27% 12% 1	3440
September	1st to 10th	Night	35% 7% 14% 28% 14% 1	1900
	11th to 20th	Night	33% 8% 14% 33% 12% 1	1900
	21st to end	Night	40% 7% 13% 29% 10% 1	2166
October	1st to 10th	Night	45% 7% 12% 21% 15%	2280
	11th to 20th	Night	51% 8% 14% 18% 8%	2275
	21st to end	Night	57% 8% 12% 15% 9%	2479
November	1st to 10th	Night	49% 7% 15% 20% 9% 1	2430
	11th to 20th	Night	53% 8% 12% 16% 8% 1	2660
	21st to end	Night	60% 8% 13% 15% 5%	2660
December	1st to 10th	Night	67% 8% 11% 12% 3	2660
	11th to 20th	Night	62% 6% 10% 13% 8% 1	3288
	21st to end	Night	73% 7% 7% 11% 3	4884

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	22% 24% 36% 14% 4	180
	11th to 20th	Day	29% 23% 34% 11% 2	180
	21st to end	Day	23% 22% 38% 13% 5%	256
February	1st to 10th	Day	29% 29% 30% 9% 3	270
	11th to 20th	Day	28% 29% 39% 4 1	270
	21st to end	Day	31% 28% 30% 10% 1	354
March	1st to 10th	Day	26% 22% 36% 13% 3	460
	11th to 20th	Day	27% 19% 35% 15% 3 1	460
	21st to end	Day	31% 24% 28% 13% 4	506
April	1st to 10th	Day	29% 23% 31% 12% 5%	460
	11th to 20th	Day	35% 22% 18% 16% 7% 2	452
	21st to end	Day	29% 22% 31% 10% 7% 1	460
May	1st to 10th	Day	25% 17% 32% 18% 5% 2	463
	11th to 20th	Day	18% 19% 34% 20% 7% 2	487
	21st to end	Day	19% 17% 32% 20% 9% 3	529
June	1st to 10th	Day	22% 14% 34% 20% 9% 1	490
	11th to 20th	Day	15% 18% 32% 24% 10% 1	490
	21st to end	Day	20% 15% 34% 19% 10% 1	490
July	1st to 10th	Day	11% 9% 32% 34% 11% 3	485
	11th to 20th	Day	13% 12% 33% 26% 12% 3	484
	21st to end	Day	15% 9% 35% 28% 10% 4	532
August	1st to 10th	Day	15% 8% 31% 28% 13% 4	486
	11th to 20th	Day	12% 9% 30% 29% 15% 5%	479
	21st to end	Day	14% 13% 29% 25% 12% 6%	539
September	1st to 10th	Day	15% 15% 30% 22% 11% 7%	490
	11th to 20th	Day	12% 12% 25% 24% 16% 11%	490
	21st to end	Day	19% 14% 29% 21% 12% 6%	490
October	1st to 10th	Day	24% 19% 26% 19% 9% 3	490
	11th to 20th	Day	25% 24% 29% 16% 4 2	486
	21st to end	Day	31% 19% 30% 16% 4	444
November	1st to 10th	Day	23% 21% 32% 17% 6% 1	338
	11th to 20th	Day	29% 21% 32% 14% 3 2	180
	21st to end	Day	29% 26% 33% 8% 5%	180
December	1st to 10th	Day	29% 21% 38% 10% 2	180
	11th to 20th	Day	33% 28% 30% 6% 3 1	180
	21st to end	Day	31% 25% 29% 12% 3 1	198
January	1st to 10th	Night	25% 21% 35% 16% 3	760
	11th to 20th	Night	26% 21% 31% 17% 4 1	760
	21st to end	Night	20% 16% 38% 22% 5%	836
February	1st to 10th	Night	22% 21% 35% 19% 2	760
	11th to 20th	Night	21% 21% 42% 14% 3	743
	21st to end	Night	23% 23% 32% 19% 3	628
March	1st to 10th	Night	25% 19% 33% 19% 3	760
	11th to 20th	Night	24% 23% 32% 17% 4 1	760
	21st to end	Night	22% 18% 32% 21% 7%	836
April	1st to 10th	Night	27% 17% 32% 19% 4	760
	11th to 20th	Night	23% 22% 29% 19% 6%	751
	21st to end	Night	24% 17% 29% 22% 7% 1	651
May	1st to 10th	Night	20% 13% 31% 26% 10% 1	380
	11th to 20th	Night	20% 11% 34% 27% 7%	374
	21st to end	Night	11% 10% 40% 27% 11%	411
June	1st to 10th	Night	16% 12% 31% 33% 8%	380
	11th to 20th	Night	14% 10% 36% 29% 11% 1	380
	21st to end	Night	20% 9% 30% 28% 12%	380
July	1st to 10th	Night	7% 9% 33% 36% 14% 1	370
	11th to 20th	Night	11% 7% 29% 41% 11% 1	368
	21st to end	Night	10% 3 33% 43% 12% 1	416
August	1st to 10th	Night	11% 6% 27% 38% 18%	476
	11th to 20th	Night	12% 4 25% 36% 20% 3	564
	21st to end	Night	12% 8% 32% 30% 16% 2	813
September	1st to 10th	Night	14% 9% 32% 27% 16% 2	760
	11th to 20th	Night	15% 7% 23% 29% 21% 3	760
	21st to end	Night	18% 12% 24% 25% 19% 2	760
October	1st to 10th	Night	23% 13% 27% 22% 13% 2	760
	11th to 20th	Night	25% 16% 32% 19% 8% 1	759
	21st to end	Night	27% 18% 29% 22% 5%	792
November	1st to 10th	Night	25% 15% 32% 21% 6% 1	740
	11th to 20th	Night	24% 20% 33% 15% 8% 1	760
	21st to end	Night	31% 18% 28% 18% 5%	760
December	1st to 10th	Night	29% 19% 34% 16% 2	760
	11th to 20th	Night	28% 19% 31% 19% 2 1	760
	21st to end	Night	33% 17% 31% 16% 2	836

Page generated at 2024-10-17 13:09:42. Version ac07

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