Goheenville
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Goheenville clear sky chart from 2005-11-06 to 2025-10-04.

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% 11% 4 9% 5% 4 4 4 5% 7% 30%	126338
	Night	18% 12% 4 9% 5% 4 4 3 4 6% 30%	123015
Transparency	Day	53% 6% 10% 20% 10% 1	129937
	Night	54% 5% 10% 19% 11% 1	127485
Seeing	Day	24% 15% 27% 20% 10% 3	15865
	Night	23% 13% 27% 26% 11% 1	25415

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	16% 20% 9% 23% 5% 3 2 2 2 3 13%	3850
	11th to 20th	Day	12% 21% 10% 20% 9% 6% 2 2 2 2 12%	4060
	21st to end	Day	21% 19% 7% 12% 7% 5% 3 3 3 4 16%	4466
February	1st to 10th	Day	20% 19% 6% 11% 8% 4 3 3 3 4 20%	1800
	11th to 20th	Day	18% 15% 6% 14% 6% 6% 3 3 4 5% 20%	1753
	21st to end	Day	21% 16% 4 11% 6% 4 3 3 4 6% 23%	1632
March	1st to 10th	Day	17% 13% 6% 8% 4 3 3 3 4 5% 33%	4935
	11th to 20th	Day	14% 12% 5% 7% 5% 4 5% 3 4 6% 34%	4980
	21st to end	Day	18% 11% 4 9% 5% 4 4 3 4 6% 31%	5465
April	1st to 10th	Day	18% 15% 3 7% 4 5% 4 4 6% 6% 28%	2342
	11th to 20th	Day	18% 12% 2 8% 5% 5% 4 3 5% 5% 33%	2374
	21st to end	Day	23% 9% 3 7% 4 4 3 3 4 6% 34%	2594
May	1st to 10th	Day	23% 9% 3 8% 5% 5% 5% 4 5% 7% 26%	5862
	11th to 20th	Day	21% 8% 3 8% 5% 5% 5% 4 6% 8% 28%	5947
	21st to end	Day	21% 7% 2 6% 4 4 5% 4 6% 8% 32%	6934
June	1st to 10th	Day	16% 7% 2 6% 5% 5% 5% 4 7% 8% 33%	2800
	11th to 20th	Day	17% 7% 3 7% 4 4 5% 4 7% 9% 33%	2800
	21st to end	Day	16% 6% 2 6% 5% 4 5% 4 6% 10% 37%	2800
July	1st to 10th	Day	12% 7% 2 6% 5% 5% 6% 4 5% 9% 40%	6360
	11th to 20th	Day	13% 7% 2 7% 6% 5% 5% 5% 7% 10% 34%	5958
	21st to end	Day	12% 6% 2 7% 5% 5% 5% 4 6% 8% 41%	6424
August	1st to 10th	Day	18% 8% 3 8% 5% 5% 6% 5% 6% 7% 29%	4234
	11th to 20th	Day	14% 6% 3 7% 5% 5% 5% 5% 6% 8% 35%	4174
	21st to end	Day	11% 5% 2 6% 5% 5% 5% 5% 7% 10% 39%	4397
September	1st to 10th	Day	18% 6% 2 5% 4 3 4 3 4 7% 44%	2400
	11th to 20th	Day	13% 6% 2 5% 4 4 4 4 6% 8% 44%	2265
	21st to end	Day	22% 7% 3 6% 4 3 4 4 6% 7% 33%	2165
October	1st to 10th	Day	18% 7% 2 7% 4 4 3 3 6% 7% 38%	1930
	11th to 20th	Day	22% 9% 3 6% 4 4 5% 3 5% 5% 34%	1900
	21st to end	Day	24% 11% 3 7% 4 3 4 3 4 7% 30%	2090
November	1st to 10th	Day	13% 9% 3 7% 4 5% 4 4 5% 6% 41%	1897
	11th to 20th	Day	18% 16% 4 7% 4 4 4 3 5% 6% 30%	1600
	21st to end	Day	20% 18% 6% 7% 5% 4 4 3 5% 6% 22%	1600
December	1st to 10th	Day	20% 18% 9% 21% 4 4 3 2 3 2 14%	2600
	11th to 20th	Day	23% 18% 7% 9% 4 3 3 2 3 4 22%	2990
	21st to end	Day	25% 22% 6% 10% 4 3 3 3 3 4 16%	3960
January	1st to 10th	Night	15% 18% 8% 24% 5% 3 3 2 3 4 14%	6091
	11th to 20th	Night	14% 18% 9% 18% 8% 6% 4 2 3 4 13%	5900
	21st to end	Night	23% 16% 7% 12% 6% 5% 5% 2 3 3 18%	6490
February	1st to 10th	Night	21% 14% 6% 12% 7% 5% 5% 3 3 3 23%	2600
	11th to 20th	Night	19% 14% 5% 13% 6% 5% 5% 3 4 5% 22%	2533
	21st to end	Night	20% 13% 4 11% 7% 4 4 4 4 5% 24%	1994
March	1st to 10th	Night	22% 12% 6% 8% 6% 3 3 2 4 5% 30%	4918
	11th to 20th	Night	15% 11% 5% 6% 4 3 3 3 4 6% 40%	4980
	21st to end	Night	18% 11% 4 7% 5% 4 4 3 4 5% 36%	5467
April	1st to 10th	Night	20% 13% 4 7% 5% 4 4 2 4 5% 31%	2056
	11th to 20th	Night	18% 10% 2 7% 4 3 4 3 5% 6% 37%	1975
	21st to end	Night	16% 9% 2 6% 5% 5% 4 3 5% 8% 36%	1822
May	1st to 10th	Night	29% 10% 3 6% 4 3 4 3 5% 6% 26%	4033
	11th to 20th	Night	21% 10% 3 7% 4 4 4 3 5% 6% 34%	3941
	21st to end	Night	22% 7% 2 6% 3 4 4 3 6% 8% 35%	3920
June	1st to 10th	Night	12% 6% 2 6% 5% 5% 4 4 5% 7% 44%	1600
	11th to 20th	Night	13% 6% 3 6% 4 5% 4 3 7% 9% 40%	1600
	21st to end	Night	13% 5% 2 6% 5% 4 6% 4 6% 10% 40%	1600
July	1st to 10th	Night	14% 7% 3 7% 4 4 4 3 5% 8% 42%	3598
	11th to 20th	Night	13% 6% 2 7% 5% 5% 5% 5% 7% 9% 36%	3981
	21st to end	Night	12% 6% 2 6% 4 4 4 3 5% 8% 45%	4427
August	1st to 10th	Night	16% 8% 3 8% 4 4 4 4 5% 7% 37%	2915
	11th to 20th	Night	17% 6% 2 6% 4 4 4 3 4 8% 42%	2875
	21st to end	Night	10% 5% 1 6% 4 5% 5% 4 7% 9% 45%	3454
September	1st to 10th	Night	14% 6% 2 5% 3 4 4 3 5% 6% 50%	2000
	11th to 20th	Night	10% 4 2 6% 3 4 3 3 6% 7% 52%	2130
	21st to end	Night	20% 7% 3 6% 5% 4 3 3 5% 8% 37%	2235
October	1st to 10th	Night	16% 6% 2 5% 4 4 4 4 5% 6% 43%	2317
	11th to 20th	Night	20% 7% 2 6% 4 4 4 3 4 6% 39%	2280
	21st to end	Night	25% 10% 2 5% 4 3 4 3 4 6% 33%	2508
November	1st to 10th	Night	15% 9% 2 6% 3 4 4 3 5% 6% 42%	2394
	11th to 20th	Night	19% 14% 4 7% 4 4 4 4 5% 6% 29%	2800
	21st to end	Night	20% 15% 4 8% 4 4 4 4 5% 5% 27%	2800
December	1st to 10th	Night	18% 17% 11% 15% 4 4 3 3 4 5% 15%	4580
	11th to 20th	Night	24% 16% 7% 11% 5% 3 3 2 3 4 22%	5205
	21st to end	Night	23% 19% 5% 10% 5% 4 4 3 4 5% 17%	6996

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	79% 3 6% 8% 4	3851
	11th to 20th	Day	80% 3 5% 8% 3 1	4060
	21st to end	Day	74% 4 7% 10% 5%	4466
February	1st to 10th	Day	70% 3 8% 13% 6%	1800
	11th to 20th	Day	67% 4 9% 14% 6%	1762
	21st to end	Day	64% 4 9% 15% 7% 1	1632
March	1st to 10th	Day	54% 4 10% 23% 8% 1	4935
	11th to 20th	Day	51% 5% 15% 20% 8% 2	4980
	21st to end	Day	54% 4 8% 20% 12% 1	5465
April	1st to 10th	Day	55% 5% 10% 16% 11% 2	2342
	11th to 20th	Day	53% 5% 10% 18% 13% 2	2374
	21st to end	Day	52% 4 10% 20% 13% 2	2594
May	1st to 10th	Day	57% 7% 8% 17% 8% 3	5897
	11th to 20th	Day	53% 7% 10% 21% 9% 1	5951
	21st to end	Day	48% 8% 12% 20% 10% 2	6949
June	1st to 10th	Day	46% 8% 11% 22% 11% 1	2800
	11th to 20th	Day	46% 8% 12% 20% 12% 1	2800
	21st to end	Day	42% 9% 12% 25% 12% 1	2800
July	1st to 10th	Day	42% 7% 9% 26% 14% 1	6290
	11th to 20th	Day	45% 6% 13% 25% 11%	5887
	21st to end	Day	40% 6% 10% 24% 20% 1	6240
August	1st to 10th	Day	52% 7% 12% 20% 8%	4221
	11th to 20th	Day	44% 6% 12% 27% 10% 1	4213
	21st to end	Day	38% 8% 13% 27% 12% 2	4397
September	1st to 10th	Day	41% 6% 9% 23% 18% 3	2400
	11th to 20th	Day	36% 7% 14% 26% 16% 1	2265
	21st to end	Day	49% 6% 11% 20% 13%	2165
October	1st to 10th	Day	37% 5% 10% 29% 18% 1	3190
	11th to 20th	Day	46% 5% 10% 21% 13% 4	3140
	21st to end	Day	40% 4 11% 29% 15% 1	3428
November	1st to 10th	Day	43% 6% 12% 19% 17% 2	1897
	11th to 20th	Day	56% 5% 11% 17% 9% 2	1600
	21st to end	Day	63% 5% 12% 15% 5% 1	1600
December	1st to 10th	Day	78% 4 8% 8% 3	2600
	11th to 20th	Day	68% 3 11% 15% 4	2986
	21st to end	Day	74% 3 8% 10% 5%	3960
January	1st to 10th	Night	76% 3 7% 11% 3	6091
	11th to 20th	Night	77% 4 8% 8% 2	5900
	21st to end	Night	73% 3 8% 10% 5% 1	6490
February	1st to 10th	Night	67% 4 8% 15% 6%	2600
	11th to 20th	Night	65% 4 10% 14% 6%	2535
	21st to end	Night	62% 5% 9% 15% 9% 1	1994
March	1st to 10th	Night	58% 4 10% 21% 8%	4918
	11th to 20th	Night	46% 4 15% 24% 8% 3	4980
	21st to end	Night	51% 4 10% 17% 17% 1	5467
April	1st to 10th	Night	55% 5% 8% 17% 13% 1	2056
	11th to 20th	Night	48% 6% 11% 18% 15% 3	1975
	21st to end	Night	47% 5% 11% 23% 12% 3	1822
May	1st to 10th	Night	59% 6% 9% 14% 10% 3	4060
	11th to 20th	Night	50% 7% 9% 22% 10% 1	3942
	21st to end	Night	46% 8% 11% 22% 11% 3	3927
June	1st to 10th	Night	38% 8% 12% 25% 15% 2	1600
	11th to 20th	Night	39% 9% 13% 24% 13% 2	1600
	21st to end	Night	39% 9% 12% 22% 16% 1	1600
July	1st to 10th	Night	42% 6% 9% 24% 17% 2	3560
	11th to 20th	Night	42% 7% 16% 22% 12% 1	3932
	21st to end	Night	38% 6% 10% 21% 24% 1	4297
August	1st to 10th	Night	47% 7% 13% 22% 11% 1	2904
	11th to 20th	Night	42% 6% 9% 30% 12% 1	2902
	21st to end	Night	34% 7% 14% 29% 13% 2	3454
September	1st to 10th	Night	35% 6% 12% 23% 20% 4	2000
	11th to 20th	Night	30% 7% 12% 28% 22% 1	2130
	21st to end	Night	48% 6% 11% 19% 15% 1	2235
October	1st to 10th	Night	37% 5% 7% 26% 23% 1	3837
	11th to 20th	Night	40% 5% 11% 22% 16% 7%	3779
	21st to end	Night	39% 4 11% 26% 19% 1	4120
November	1st to 10th	Night	42% 5% 11% 22% 16% 4	2394
	11th to 20th	Night	55% 5% 10% 18% 10% 3	2800
	21st to end	Night	58% 6% 10% 19% 6% 1	2800
December	1st to 10th	Night	73% 4 10% 10% 3	4580
	11th to 20th	Night	68% 3 11% 14% 3	5208
	21st to end	Night	70% 5% 9% 13% 3	6996

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	37% 25% 24% 10% 3	255
	11th to 20th	Day	35% 29% 28% 6% 2	300
	21st to end	Day	32% 26% 32% 8% 2	330
February	1st to 10th	Day	34% 25% 33% 6% 1	300
	11th to 20th	Day	41% 24% 28% 6%	300
	21st to end	Day	35% 28% 29% 7%	311
March	1st to 10th	Day	31% 24% 29% 13% 3	500
	11th to 20th	Day	34% 19% 31% 11% 4 1	500
	21st to end	Day	35% 21% 26% 14% 4 1	550
April	1st to 10th	Day	32% 20% 26% 15% 5% 1	500
	11th to 20th	Day	28% 21% 28% 13% 8% 2	492
	21st to end	Day	29% 19% 28% 16% 5% 2	500
May	1st to 10th	Day	30% 17% 26% 16% 7% 3	503
	11th to 20th	Day	25% 17% 27% 19% 9% 3	527
	21st to end	Day	20% 11% 27% 23% 14% 5%	573
June	1st to 10th	Day	19% 14% 30% 24% 11% 2	530
	11th to 20th	Day	22% 13% 25% 25% 11% 4	530
	21st to end	Day	18% 11% 31% 23% 14% 2	530
July	1st to 10th	Day	14% 6% 24% 28% 19% 8%	525
	11th to 20th	Day	12% 7% 29% 29% 16% 7%	524
	21st to end	Day	14% 5% 27% 31% 16% 6%	576
August	1st to 10th	Day	14% 8% 24% 28% 19% 7%	526
	11th to 20th	Day	16% 6% 24% 29% 16% 9%	519
	21st to end	Day	10% 8% 26% 30% 17% 9%	583
September	1st to 10th	Day	17% 9% 22% 25% 18% 8%	530
	11th to 20th	Day	11% 4 22% 33% 22% 9%	530
	21st to end	Day	27% 11% 23% 23% 12% 4	530
October	1st to 10th	Day	20% 12% 25% 24% 16% 4	502
	11th to 20th	Day	26% 16% 27% 21% 8% 2	490
	21st to end	Day	31% 15% 30% 17% 6%	539
November	1st to 10th	Day	19% 19% 31% 19% 10% 2	440
	11th to 20th	Day	31% 21% 32% 13% 2 2	200
	21st to end	Day	26% 25% 38% 10% 2	200
December	1st to 10th	Day	33% 30% 26% 9% 3 1	200
	11th to 20th	Day	35% 21% 34% 8% 3	200
	21st to end	Day	40% 19% 26% 11% 4	220
January	1st to 10th	Night	29% 23% 33% 12% 4	800
	11th to 20th	Night	32% 21% 31% 14% 3	800
	21st to end	Night	29% 22% 31% 17% 2	880
February	1st to 10th	Night	32% 17% 29% 21% 1	800
	11th to 20th	Night	31% 20% 33% 14% 1	783
	21st to end	Night	29% 19% 33% 18% 2	660
March	1st to 10th	Night	26% 19% 33% 20% 2	800
	11th to 20th	Night	29% 19% 27% 19% 6%	800
	21st to end	Night	25% 16% 35% 19% 5% 1	880
April	1st to 10th	Night	28% 18% 29% 20% 6%	800
	11th to 20th	Night	24% 15% 31% 21% 8% 1	791
	21st to end	Night	20% 11% 34% 28% 6%	622
May	1st to 10th	Night	24% 11% 25% 32% 9% 1	600
	11th to 20th	Night	23% 8% 28% 33% 8%	552
	21st to end	Night	14% 6% 24% 33% 21% 2	433
June	1st to 10th	Night	13% 4 29% 39% 14% 1	400
	11th to 20th	Night	12% 6% 26% 38% 18% 1	400
	21st to end	Night	13% 4 28% 39% 16% 1	400
July	1st to 10th	Night	12% 2 19% 42% 22% 3	390
	11th to 20th	Night	12% 5% 16% 39% 26% 3	547
	21st to end	Night	13% 3 16% 41% 26% 1	657
August	1st to 10th	Night	10% 3 17% 46% 23% 2	597
	11th to 20th	Night	14% 4 14% 38% 27% 4	594
	21st to end	Night	12% 4 18% 37% 27% 3	800
September	1st to 10th	Night	16% 4 21% 34% 22% 3	800
	11th to 20th	Night	12% 5% 17% 35% 29% 4	800
	21st to end	Night	21% 10% 21% 28% 16% 4	800
October	1st to 10th	Night	19% 8% 23% 29% 20% 1	773
	11th to 20th	Night	23% 13% 28% 26% 9% 1	760
	21st to end	Night	29% 13% 26% 26% 6%	836
November	1st to 10th	Night	20% 11% 30% 28% 10%	780
	11th to 20th	Night	29% 15% 27% 22% 6% 1	800
	21st to end	Night	29% 16% 31% 18% 5%	800
December	1st to 10th	Night	33% 21% 27% 15% 4	800
	11th to 20th	Night	31% 21% 28% 17% 3	800
	21st to end	Night	31% 18% 30% 19% 2	880

Page generated at 2025-10-01 01:39:05. Version ac07

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