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 2024-02-20.

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	17% 10% 4 8% 6% 4 5% 4 5% 6% 32%	78229
	Night	16% 11% 4 8% 6% 3 5% 4 5% 6% 31%	80956
Transparency	Day	52% 7% 11% 18% 10% 1	77934
	Night	53% 8% 12% 18% 9% 1	80785
Seeing	Day	22% 18% 31% 18% 8% 2	13439
	Night	22% 15% 32% 23% 8% 1	22768

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% 16% 6% 11% 9% 4 5% 4 5% 5% 21%	2517
	11th to 20th	Day	13% 15% 8% 12% 9% 5% 6% 4 4 4 22%	2520
	21st to end	Day	16% 20% 7% 13% 8% 4 4 4 3 4 16%	2973
February	1st to 10th	Day	14% 15% 6% 11% 9% 5% 5% 5% 4 5% 23%	1710
	11th to 20th	Day	11% 14% 6% 10% 7% 4 5% 4 4 5% 29%	1654
	21st to end	Day	18% 15% 4 9% 7% 5% 5% 4 5% 4 24%	1454
March	1st to 10th	Day	14% 13% 5% 11% 8% 4 6% 3 4 5% 28%	1839
	11th to 20th	Day	14% 12% 5% 8% 8% 4 5% 5% 4 4 30%	1980
	21st to end	Day	17% 11% 4 8% 5% 2 3 3 4 5% 37%	2263
April	1st to 10th	Day	21% 12% 4 5% 5% 3 4 4 5% 6% 31%	2160
	11th to 20th	Day	21% 9% 3 5% 5% 3 3 4 3 5% 38%	2134
	21st to end	Day	22% 11% 4 7% 5% 3 4 4 4 5% 32%	2278
May	1st to 10th	Day	19% 9% 3 6% 6% 3 4 4 6% 5% 35%	2520
	11th to 20th	Day	17% 8% 3 7% 6% 3 4 4 5% 7% 38%	2478
	21st to end	Day	14% 6% 3 5% 6% 4 5% 5% 6% 6% 39%	2725
June	1st to 10th	Day	21% 7% 4 6% 6% 3 5% 5% 5% 7% 31%	2520
	11th to 20th	Day	15% 5% 3 6% 5% 4 5% 5% 6% 9% 38%	2520
	21st to end	Day	17% 6% 3 7% 6% 4 6% 5% 5% 7% 33%	2520
July	1st to 10th	Day	11% 5% 3 6% 6% 4 5% 6% 6% 8% 39%	2520
	11th to 20th	Day	12% 5% 3 6% 6% 3 5% 6% 7% 11% 37%	2520
	21st to end	Day	13% 5% 2 6% 6% 4 6% 6% 7% 9% 37%	2744
August	1st to 10th	Day	12% 6% 3 6% 6% 3 6% 6% 6% 8% 38%	2412
	11th to 20th	Day	13% 6% 2 7% 6% 4 6% 6% 6% 8% 37%	2303
	21st to end	Day	15% 6% 3 5% 6% 3 5% 5% 7% 8% 36%	2379
September	1st to 10th	Day	15% 5% 3 5% 6% 4 5% 5% 6% 8% 40%	2160
	11th to 20th	Day	13% 6% 2 5% 5% 3 4 5% 5% 8% 45%	2160
	21st to end	Day	17% 6% 2 6% 5% 3 4 4 6% 7% 38%	1907
October	1st to 10th	Day	21% 8% 3 7% 5% 4 4 4 5% 6% 34%	1800
	11th to 20th	Day	22% 10% 3 7% 7% 3 5% 4 5% 6% 28%	1800
	21st to end	Day	26% 10% 4 7% 6% 4 5% 4 4 5% 25%	1877
November	1st to 10th	Day	14% 9% 3 7% 7% 4 5% 5% 5% 7% 34%	1644
	11th to 20th	Day	18% 12% 6% 8% 6% 4 5% 4 4 6% 28%	1520
	21st to end	Day	20% 15% 6% 9% 7% 4 5% 4 4 6% 20%	1520
December	1st to 10th	Day	20% 18% 7% 10% 8% 3 4 4 4 4 17%	1520
	11th to 20th	Day	19% 14% 6% 8% 6% 3 4 4 4 5% 26%	1906
	21st to end	Day	27% 17% 6% 12% 6% 3 3 3 3 3 19%	2772
January	1st to 10th	Night	17% 14% 7% 12% 8% 4 5% 4 5% 6% 19%	4429
	11th to 20th	Night	12% 14% 5% 11% 11% 5% 6% 5% 5% 5% 21%	4440
	21st to end	Night	16% 18% 8% 10% 7% 5% 5% 4 3 4 19%	4678
February	1st to 10th	Night	13% 15% 6% 11% 8% 3 5% 5% 6% 5% 23%	2470
	11th to 20th	Night	13% 12% 6% 10% 7% 4 4 4 5% 5% 30%	2397
	21st to end	Night	14% 12% 5% 8% 7% 4 5% 4 6% 5% 29%	1800
March	1st to 10th	Night	15% 12% 6% 9% 8% 3 5% 3 4 5% 30%	2106
	11th to 20th	Night	15% 13% 5% 7% 5% 3 3 3 5% 7% 33%	1979
	21st to end	Night	15% 9% 4 6% 6% 3 4 4 4 5% 38%	2093
April	1st to 10th	Night	20% 9% 4 7% 5% 3 3 4 4 5% 35%	1800
	11th to 20th	Night	19% 8% 4 6% 6% 4 4 4 3 6% 37%	1775
	21st to end	Night	20% 10% 3 7% 5% 3 4 5% 4 6% 32%	1698
May	1st to 10th	Night	19% 8% 3 5% 4 3 4 4 5% 5% 38%	1440
	11th to 20th	Night	17% 7% 3 5% 4 3 5% 4 6% 7% 41%	1415
	21st to end	Night	13% 5% 3 4 4 3 5% 5% 5% 8% 45%	1550
June	1st to 10th	Night	16% 5% 3 5% 7% 3 5% 6% 6% 8% 35%	1440
	11th to 20th	Night	12% 6% 3 6% 6% 3 5% 5% 5% 6% 43%	1440
	21st to end	Night	15% 8% 3 6% 4 4 5% 5% 6% 9% 36%	1440
July	1st to 10th	Night	10% 4 2 6% 5% 3 6% 5% 5% 8% 46%	1440
	11th to 20th	Night	10% 5% 2 6% 6% 4 4 5% 6% 9% 43%	1440
	21st to end	Night	9% 4 2 5% 6% 3 6% 6% 7% 10% 44%	1574
August	1st to 10th	Night	9% 6% 2 6% 5% 4 4 6% 6% 8% 44%	1524
	11th to 20th	Night	9% 5% 2 6% 6% 3 5% 6% 5% 8% 45%	1598
	21st to end	Night	11% 6% 2 5% 5% 3 4 5% 5% 8% 45%	1958
September	1st to 10th	Night	12% 5% 4 5% 5% 3 4 4 6% 6% 46%	1800
	11th to 20th	Night	14% 5% 2 3 4 3 4 4 5% 6% 49%	1800
	21st to end	Night	16% 7% 2 5% 4 2 3 4 6% 6% 43%	2051
October	1st to 10th	Night	19% 8% 3 5% 5% 3 4 5% 5% 6% 37%	2160
	11th to 20th	Night	20% 10% 3 7% 6% 4 5% 5% 5% 6% 30%	2160
	21st to end	Night	22% 11% 4 7% 6% 3 4 4 5% 7% 27%	2479
November	1st to 10th	Night	17% 11% 3 7% 5% 3 5% 4 4 6% 36%	2430
	11th to 20th	Night	17% 11% 4 6% 7% 4 5% 5% 5% 6% 29%	2660
	21st to end	Night	20% 14% 4 8% 6% 3 5% 4 5% 7% 24%	2660
December	1st to 10th	Night	18% 18% 6% 10% 7% 3 6% 5% 5% 6% 18%	2660
	11th to 20th	Night	20% 15% 6% 8% 7% 3 4 4 3 4 26%	3288
	21st to end	Night	28% 17% 5% 12% 6% 3 4 3 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	56% 6% 11% 15% 10% 1	1663
	21st to end	Day	61% 7% 10% 11% 10% 1	1454
March	1st to 10th	Day	59% 5% 11% 14% 10% 2	1842
	11th to 20th	Day	56% 6% 10% 14% 11% 2	1980
	21st to end	Day	50% 5% 8% 18% 14% 6%	2263
April	1st to 10th	Day	54% 5% 8% 17% 12% 3	2160
	11th to 20th	Day	49% 6% 7% 20% 16% 2	2134
	21st to end	Day	54% 6% 9% 14% 14% 4	2278
May	1st to 10th	Day	49% 6% 10% 16% 15% 3	2520
	11th to 20th	Day	46% 6% 9% 21% 16% 2	2482
	21st to end	Day	44% 8% 13% 19% 13% 2	2725
June	1st to 10th	Day	52% 7% 10% 17% 12% 1	2520
	11th to 20th	Day	42% 9% 11% 22% 13% 3	2520
	21st to end	Day	48% 9% 13% 19% 11% 1	2520
July	1st to 10th	Day	38% 8% 13% 26% 14% 1	2450
	11th to 20th	Day	38% 9% 18% 23% 11% 1	2445
	21st to end	Day	41% 10% 15% 24% 10%	2591
August	1st to 10th	Day	41% 10% 15% 24% 10%	2398
	11th to 20th	Day	42% 10% 16% 22% 9% 1	2303
	21st to end	Day	42% 8% 15% 24% 11% 1	2379
September	1st to 10th	Day	40% 9% 14% 26% 11%	2160
	11th to 20th	Day	37% 8% 14% 28% 14%	2160
	21st to end	Day	45% 7% 13% 25% 9%	1907
October	1st to 10th	Day	51% 6% 12% 20% 11% 1	1800
	11th to 20th	Day	55% 9% 13% 16% 6% 1	1800
	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	2399
	21st to end	Night	55% 7% 11% 17% 10% 1	1800
March	1st to 10th	Night	56% 5% 12% 17% 9% 2	2116
	11th to 20th	Night	51% 6% 12% 19% 11% 2	1980
	21st to end	Night	47% 6% 9% 20% 14% 4	2093
April	1st to 10th	Night	51% 6% 9% 18% 14% 2	1800
	11th to 20th	Night	49% 4 9% 21% 15% 2	1775
	21st to end	Night	52% 6% 8% 16% 15% 3	1698
May	1st to 10th	Night	47% 6% 7% 20% 16% 4	1440
	11th to 20th	Night	41% 6% 11% 22% 16% 3	1416
	21st to end	Night	36% 8% 15% 19% 19% 3	1551
June	1st to 10th	Night	44% 9% 14% 21% 11% 1	1440
	11th to 20th	Night	40% 8% 12% 22% 17% 2	1440
	21st to end	Night	43% 11% 14% 18% 13% 1	1440
July	1st to 10th	Night	32% 10% 13% 25% 18% 3	1400
	11th to 20th	Night	37% 7% 13% 30% 13%	1392
	21st to end	Night	33% 9% 19% 25% 13% 1	1486
August	1st to 10th	Night	36% 11% 17% 22% 13% 1	1514
	11th to 20th	Night	35% 10% 17% 27% 11% 1	1598
	21st to end	Night	35% 9% 16% 27% 12% 1	1958
September	1st to 10th	Night	36% 8% 15% 27% 14% 1	1800
	11th to 20th	Night	34% 8% 14% 32% 11% 1	1800
	21st to end	Night	40% 7% 13% 30% 9% 1	2051
October	1st to 10th	Night	46% 7% 12% 20% 15%	2160
	11th to 20th	Night	52% 8% 14% 18% 8% 1	2160
	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% 30% 38% 4 1	267
	21st to end	Day	32% 27% 30% 10% 1	320
March	1st to 10th	Day	26% 21% 36% 14% 3	420
	11th to 20th	Day	28% 20% 34% 15% 3 1	420
	21st to end	Day	32% 22% 28% 13% 4	462
April	1st to 10th	Day	29% 23% 31% 12% 5%	420
	11th to 20th	Day	34% 20% 19% 18% 8% 2	412
	21st to end	Day	29% 22% 31% 10% 7% 1	420
May	1st to 10th	Day	26% 17% 32% 17% 5% 3	423
	11th to 20th	Day	20% 19% 34% 19% 6% 2	447
	21st to end	Day	19% 16% 33% 19% 9% 3	485
June	1st to 10th	Day	23% 14% 35% 19% 8% 1	450
	11th to 20th	Day	15% 18% 31% 24% 10% 2	450
	21st to end	Day	18% 14% 34% 20% 11% 2	450
July	1st to 10th	Day	11% 8% 31% 36% 12% 3	445
	11th to 20th	Day	13% 12% 32% 26% 13% 3	444
	21st to end	Day	15% 9% 36% 27% 9% 4	488
August	1st to 10th	Day	14% 8% 33% 29% 13% 4	446
	11th to 20th	Day	11% 9% 31% 29% 16% 5%	439
	21st to end	Day	15% 13% 30% 24% 12% 7%	495
September	1st to 10th	Day	15% 14% 30% 22% 12% 7%	450
	11th to 20th	Day	13% 13% 27% 23% 14% 10%	450
	21st to end	Day	19% 14% 30% 19% 12% 6%	450
October	1st to 10th	Day	24% 19% 25% 19% 10% 4	450
	11th to 20th	Day	26% 24% 30% 16% 4 2	450
	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	742
	21st to end	Night	23% 23% 32% 19% 3	592
March	1st to 10th	Night	25% 20% 33% 19% 3	720
	11th to 20th	Night	24% 22% 32% 17% 4 1	720
	21st to end	Night	22% 18% 32% 21% 7%	792
April	1st to 10th	Night	27% 18% 32% 20% 4	720
	11th to 20th	Night	23% 22% 29% 20% 6%	711
	21st to end	Night	24% 17% 29% 22% 7%	618
May	1st to 10th	Night	21% 12% 30% 26% 11% 1	360
	11th to 20th	Night	20% 11% 35% 27% 7%	354
	21st to end	Night	12% 9% 40% 28% 11%	389
June	1st to 10th	Night	16% 12% 32% 32% 8%	360
	11th to 20th	Night	14% 11% 35% 29% 11% 1	360
	21st to end	Night	19% 9% 30% 30% 13%	360
July	1st to 10th	Night	7% 9% 33% 36% 15% 1	350
	11th to 20th	Night	11% 6% 29% 42% 11% 1	348
	21st to end	Night	9% 3 33% 42% 12% 1	394
August	1st to 10th	Night	11% 6% 27% 38% 18%	450
	11th to 20th	Night	11% 3 25% 37% 20% 3	534
	21st to end	Night	12% 8% 33% 29% 17% 2	770
September	1st to 10th	Night	13% 9% 32% 27% 17% 2	720
	11th to 20th	Night	16% 8% 25% 29% 19% 3	720
	21st to end	Night	18% 13% 24% 24% 19% 2	720
October	1st to 10th	Night	24% 13% 27% 22% 13% 2	720
	11th to 20th	Night	25% 16% 33% 18% 8% 1	720
	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 2024-02-17 06:28:36. Version ac07

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