Gouldsboro
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Gouldsboro clear sky chart from 2005-11-06 to 2026-03-18.

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	15% 9% 3 8% 6% 5% 5% 4 6% 7% 33%	131387
	Night	14% 9% 4 9% 5% 5% 4 4 5% 6% 35%	130090
Transparency	Day	47% 3 11% 23% 13% 2	134904
	Night	45% 3 12% 24% 14% 2	134660
Seeing	Day	25% 20% 28% 17% 7% 2	16523
	Night	23% 20% 28% 21% 7% 1	25885

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	10% 13% 5% 13% 8% 6% 6% 4 5% 6% 25%	4661
	11th to 20th	Day	11% 12% 6% 16% 8% 5% 3 3 4 5% 28%	4668
	21st to end	Day	13% 9% 5% 10% 6% 5% 4 4 5% 6% 32%	5780
February	1st to 10th	Day	13% 12% 4 10% 7% 6% 5% 3 5% 6% 29%	1890
	11th to 20th	Day	13% 11% 4 9% 7% 6% 4 5% 5% 6% 30%	1957
	21st to end	Day	15% 12% 4 10% 7% 4 4 4 4 5% 30%	1730
March	1st to 10th	Day	19% 10% 4 8% 5% 5% 4 3 4 5% 33%	4594
	11th to 20th	Day	11% 8% 4 8% 6% 5% 5% 3 5% 7% 39%	5057
	21st to end	Day	15% 8% 3 7% 5% 4 5% 4 5% 6% 37%	5779
April	1st to 10th	Day	16% 12% 3 9% 6% 5% 4 4 4 5% 32%	2400
	11th to 20th	Day	14% 11% 3 7% 5% 4 5% 3 5% 7% 35%	2374
	21st to end	Day	14% 8% 3 8% 5% 5% 5% 4 6% 6% 35%	2400
May	1st to 10th	Day	26% 9% 3 7% 5% 4 5% 4 5% 7% 26%	6048
	11th to 20th	Day	22% 9% 3 8% 5% 5% 4 4 6% 7% 28%	6318
	21st to end	Day	19% 8% 3 7% 5% 4 5% 5% 7% 8% 29%	6949
June	1st to 10th	Day	15% 7% 3 7% 6% 5% 6% 4 7% 8% 34%	2800
	11th to 20th	Day	14% 9% 3 7% 5% 5% 6% 5% 6% 8% 32%	2800
	21st to end	Day	12% 7% 3 7% 5% 5% 5% 5% 6% 8% 36%	2800
July	1st to 10th	Day	8% 6% 3 9% 6% 6% 6% 4 7% 9% 36%	6360
	11th to 20th	Day	9% 6% 3 8% 6% 6% 6% 6% 9% 11% 30%	6360
	21st to end	Day	12% 8% 3 7% 5% 5% 5% 4 6% 9% 36%	6910
August	1st to 10th	Day	20% 8% 3 8% 4 5% 5% 4 6% 7% 29%	4234
	11th to 20th	Day	13% 7% 3 7% 4 5% 5% 5% 7% 9% 35%	3922
	21st to end	Day	15% 7% 2 5% 4 4 4 4 6% 8% 42%	4312
September	1st to 10th	Day	16% 5% 2 6% 6% 4 5% 4 6% 7% 39%	2400
	11th to 20th	Day	12% 6% 2 5% 4 4 4 3 5% 7% 46%	2380
	21st to end	Day	17% 8% 3 8% 6% 5% 4 3 5% 6% 34%	2177
October	1st to 10th	Day	15% 9% 3 7% 5% 4 4 3 5% 6% 40%	2000
	11th to 20th	Day	13% 9% 3 8% 5% 4 4 4 5% 7% 39%	2000
	21st to end	Day	17% 9% 3 10% 4 4 4 3 6% 6% 34%	2112
November	1st to 10th	Day	11% 9% 3 7% 5% 4 4 3 5% 7% 43%	1851
	11th to 20th	Day	13% 11% 3 8% 6% 4 4 3 5% 6% 36%	1890
	21st to end	Day	16% 11% 3 9% 6% 5% 6% 3 4 7% 31%	1680
December	1st to 10th	Day	11% 10% 4 12% 6% 6% 5% 4 6% 6% 31%	2680
	11th to 20th	Day	17% 12% 5% 11% 5% 5% 4 3 5% 4 31%	3066
	21st to end	Day	13% 13% 6% 13% 6% 5% 5% 4 5% 6% 25%	4048
January	1st to 10th	Night	9% 9% 6% 15% 8% 7% 6% 4 6% 7% 24%	8234
	11th to 20th	Night	11% 11% 5% 16% 8% 6% 4 3 5% 5% 26%	8198
	21st to end	Night	11% 9% 3 8% 7% 6% 6% 4 6% 7% 34%	8401
February	1st to 10th	Night	14% 12% 3 8% 6% 5% 4 4 6% 6% 34%	2730
	11th to 20th	Night	13% 10% 3 11% 6% 6% 5% 4 7% 7% 28%	2547
	21st to end	Night	13% 11% 4 9% 6% 5% 5% 4 5% 5% 31%	2076
March	1st to 10th	Night	15% 11% 4 10% 5% 4 4 3 5% 5% 35%	5448
	11th to 20th	Night	10% 8% 4 8% 5% 5% 4 4 6% 7% 41%	5057
	21st to end	Night	12% 9% 4 9% 5% 5% 4 3 5% 5% 38%	5152
April	1st to 10th	Night	14% 12% 5% 10% 6% 5% 5% 4 5% 6% 30%	2000
	11th to 20th	Night	15% 9% 4 7% 5% 4 4 4 5% 7% 36%	1975
	21st to end	Night	16% 9% 3 7% 5% 4 3 3 5% 6% 38%	2000
May	1st to 10th	Night	27% 11% 3 7% 4 4 4 3 5% 6% 26%	3936
	11th to 20th	Night	19% 13% 3 7% 4 4 4 4 5% 6% 31%	3575
	21st to end	Night	20% 8% 3 8% 5% 4 4 4 6% 7% 31%	3926
June	1st to 10th	Night	14% 7% 2 6% 4 4 4 4 6% 9% 39%	1600
	11th to 20th	Night	13% 6% 3 7% 5% 5% 4 4 6% 8% 39%	1600
	21st to end	Night	10% 5% 2 5% 4 4 5% 5% 7% 9% 44%	1600
July	1st to 10th	Night	9% 7% 3 9% 5% 5% 5% 4 6% 9% 39%	3600
	11th to 20th	Night	11% 8% 3 8% 5% 6% 5% 5% 7% 9% 33%	3600
	21st to end	Night	12% 6% 2 6% 4 4 4 3 5% 7% 47%	3926
August	1st to 10th	Night	19% 9% 2 7% 4 4 3 3 7% 7% 34%	2915
	11th to 20th	Night	15% 7% 3 6% 4 4 4 3 5% 6% 43%	3093
	21st to end	Night	11% 7% 2 5% 3 3 4 4 5% 7% 48%	3586
September	1st to 10th	Night	14% 7% 2 6% 3 4 4 3 6% 7% 45%	2000
	11th to 20th	Night	11% 6% 3 6% 4 3 2 3 5% 6% 50%	2020
	21st to end	Night	17% 8% 3 8% 4 3 4 3 5% 6% 39%	2219
October	1st to 10th	Night	17% 7% 2 6% 4 3 4 3 4 6% 43%	2400
	11th to 20th	Night	14% 8% 2 7% 4 3 4 3 5% 6% 43%	2400
	21st to end	Night	18% 10% 3 6% 4 3 4 4 5% 6% 38%	2726
November	1st to 10th	Night	10% 9% 3 7% 5% 3 4 3 5% 5% 45%	2667
	11th to 20th	Night	15% 9% 3 7% 5% 4 4 4 5% 7% 36%	2730
	21st to end	Night	12% 8% 4 9% 6% 5% 5% 4 5% 7% 34%	2935
December	1st to 10th	Night	10% 9% 4 10% 6% 5% 5% 4 6% 6% 34%	4720
	11th to 20th	Night	20% 11% 4 8% 4 4 3 3 5% 5% 33%	5348
	21st to end	Night	17% 13% 5% 10% 6% 5% 4 3 4 5% 27%	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	48% 2 10% 28% 12% 2	4662
	11th to 20th	Day	56% 2 7% 19% 12% 4	4698
	21st to end	Day	48% 3 10% 24% 15% 1	5780
February	1st to 10th	Day	53% 3 10% 20% 12% 2	1890
	11th to 20th	Day	50% 3 8% 23% 13% 1	1966
	21st to end	Day	53% 1 10% 23% 11% 2	1730
March	1st to 10th	Day	49% 2 9% 22% 12% 6%	4597
	11th to 20th	Day	42% 3 14% 28% 9% 4	5057
	21st to end	Day	45% 3 11% 14% 23% 5%	5779
April	1st to 10th	Day	52% 3 8% 21% 13% 3	2400
	11th to 20th	Day	48% 3 10% 23% 14% 2	2374
	21st to end	Day	46% 4 9% 23% 14% 4	2400
May	1st to 10th	Day	57% 4 12% 17% 9% 1	6059
	11th to 20th	Day	54% 3 10% 22% 10% 1	6322
	21st to end	Day	48% 4 12% 24% 12% 2	6949
June	1st to 10th	Day	46% 4 13% 23% 13% 1	2800
	11th to 20th	Day	47% 4 14% 22% 11% 2	2800
	21st to end	Day	43% 5% 14% 26% 12% 1	2800
July	1st to 10th	Day	43% 7% 12% 24% 13% 1	6290
	11th to 20th	Day	44% 5% 16% 24% 10%	6285
	21st to end	Day	43% 4 11% 24% 17% 1	6712
August	1st to 10th	Day	52% 4 13% 22% 9%	4221
	11th to 20th	Day	43% 4 13% 30% 9%	3960
	21st to end	Day	38% 3 10% 35% 13% 1	4312
September	1st to 10th	Day	42% 4 11% 23% 17% 2	2400
	11th to 20th	Day	36% 4 9% 26% 23% 2	2380
	21st to end	Day	49% 4 9% 19% 18% 2	2177
October	1st to 10th	Day	43% 3 8% 24% 20% 2	3260
	11th to 20th	Day	37% 3 8% 29% 17% 7%	3240
	21st to end	Day	32% 2 16% 28% 19% 4	3389
November	1st to 10th	Day	39% 2 12% 26% 19% 3	1851
	11th to 20th	Day	45% 2 9% 24% 16% 3	1890
	21st to end	Day	48% 4 12% 25% 10% 1	1680
December	1st to 10th	Day	47% 3 14% 25% 10% 1	2680
	11th to 20th	Day	51% 2 13% 21% 12% 1	3066
	21st to end	Day	55% 2 10% 19% 13% 1	4048
January	1st to 10th	Night	49% 2 11% 25% 11% 2	8234
	11th to 20th	Night	52% 3 10% 20% 11% 4	8243
	21st to end	Night	43% 3 10% 22% 20% 2	8401
February	1st to 10th	Night	46% 3 14% 23% 12% 2	2730
	11th to 20th	Night	48% 4 10% 22% 15% 2	2549
	21st to end	Night	49% 2 8% 24% 14% 3	2076
March	1st to 10th	Night	48% 2 11% 21% 13% 4	5458
	11th to 20th	Night	39% 2 17% 25% 12% 5%	5058
	21st to end	Night	45% 4 8% 17% 23% 4	5152
April	1st to 10th	Night	51% 3 9% 21% 13% 3	2000
	11th to 20th	Night	46% 4 11% 22% 17% 1	1975
	21st to end	Night	45% 3 9% 23% 17% 3	2000
May	1st to 10th	Night	58% 3 10% 18% 8% 2	3942
	11th to 20th	Night	55% 4 11% 17% 12% 1	3576
	21st to end	Night	47% 3 14% 23% 11% 1	3927
June	1st to 10th	Night	40% 5% 11% 26% 17%	1600
	11th to 20th	Night	40% 4 18% 27% 11% 1	1600
	21st to end	Night	35% 5% 16% 30% 13% 1	1600
July	1st to 10th	Night	42% 6% 15% 20% 16% 1	3560
	11th to 20th	Night	46% 6% 14% 24% 10%	3552
	21st to end	Night	36% 4 13% 27% 19% 1	3809
August	1st to 10th	Night	45% 5% 18% 22% 8%	2904
	11th to 20th	Night	42% 3 16% 28% 11%	3121
	21st to end	Night	33% 4 12% 35% 16% 1	3586
September	1st to 10th	Night	39% 4 11% 27% 17% 1	2000
	11th to 20th	Night	34% 3 9% 27% 24% 2	2020
	21st to end	Night	45% 3 9% 23% 19% 1	2219
October	1st to 10th	Night	42% 3 9% 27% 17% 2	3920
	11th to 20th	Night	33% 2 10% 28% 21% 6%	3899
	21st to end	Night	32% 2 16% 28% 18% 3	4399
November	1st to 10th	Night	37% 3 13% 24% 20% 3	2667
	11th to 20th	Night	44% 2 10% 24% 17% 3	2730
	21st to end	Night	43% 3 15% 27% 12% 1	2935
December	1st to 10th	Night	44% 3 13% 32% 7% 1	4720
	11th to 20th	Night	50% 2 11% 20% 15% 1	5348
	21st to end	Night	55% 2 9% 19% 13% 2	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	43% 25% 23% 8% 1	220
	11th to 20th	Day	44% 27% 23% 4 1	223
	21st to end	Day	33% 33% 26% 6% 2	363
February	1st to 10th	Day	35% 35% 23% 6% 1	330
	11th to 20th	Day	40% 29% 28% 4	445
	21st to end	Day	33% 33% 26% 7% 2	446
March	1st to 10th	Day	38% 22% 28% 11% 1	540
	11th to 20th	Day	33% 28% 26% 10% 3 1	528
	21st to end	Day	34% 28% 25% 9% 3 1	550
April	1st to 10th	Day	36% 26% 23% 11% 5%	500
	11th to 20th	Day	31% 25% 26% 12% 5% 1	492
	21st to end	Day	27% 24% 33% 10% 4 2	500
May	1st to 10th	Day	33% 22% 27% 10% 6% 2	503
	11th to 20th	Day	26% 19% 32% 15% 6% 1	527
	21st to end	Day	22% 13% 29% 24% 10% 1	573
June	1st to 10th	Day	21% 16% 30% 21% 10% 2	530
	11th to 20th	Day	21% 21% 24% 23% 12%	530
	21st to end	Day	16% 17% 33% 25% 8% 1	530
July	1st to 10th	Day	12% 12% 31% 27% 15% 3	525
	11th to 20th	Day	9% 10% 32% 31% 15% 2	524
	21st to end	Day	14% 12% 36% 26% 9% 3	576
August	1st to 10th	Day	14% 9% 30% 26% 15% 5%	526
	11th to 20th	Day	13% 10% 28% 30% 15% 4	519
	21st to end	Day	15% 11% 30% 26% 10% 7%	583
September	1st to 10th	Day	20% 12% 24% 24% 14% 6%	530
	11th to 20th	Day	12% 9% 31% 23% 16% 9%	530
	21st to end	Day	26% 15% 27% 20% 10% 3	530
October	1st to 10th	Day	23% 15% 26% 22% 11% 4	530
	11th to 20th	Day	23% 23% 28% 18% 6% 2	530
	21st to end	Day	24% 24% 30% 16% 5% 1	533
November	1st to 10th	Day	25% 25% 25% 17% 6% 2	425
	11th to 20th	Day	29% 27% 27% 13% 3 1	430
	21st to end	Day	39% 25% 28% 7% 1	220
December	1st to 10th	Day	33% 32% 25% 7% 2	220
	11th to 20th	Day	40% 25% 28% 5% 1	220
	21st to end	Day	34% 27% 26% 10% 2	242
January	1st to 10th	Night	26% 30% 31% 11% 2	840
	11th to 20th	Night	30% 26% 29% 14% 1	840
	21st to end	Night	21% 34% 32% 13% 1	924
February	1st to 10th	Night	31% 25% 32% 12% 1	840
	11th to 20th	Night	29% 32% 31% 8%	823
	21st to end	Night	30% 29% 28% 11% 2	692
March	1st to 10th	Night	32% 24% 30% 12% 3	840
	11th to 20th	Night	27% 28% 27% 15% 3	829
	21st to end	Night	26% 26% 30% 13% 5% 1	880
April	1st to 10th	Night	26% 26% 30% 16% 2	800
	11th to 20th	Night	25% 22% 30% 17% 5%	791
	21st to end	Night	25% 19% 31% 21% 5%	800
May	1st to 10th	Night	28% 16% 29% 21% 6% 1	560
	11th to 20th	Night	19% 16% 35% 25% 5% 1	394
	21st to end	Night	17% 12% 27% 32% 12%	433
June	1st to 10th	Night	17% 10% 27% 36% 10% 1	400
	11th to 20th	Night	15% 10% 31% 34% 9% 1	400
	21st to end	Night	12% 8% 28% 40% 11%	400
July	1st to 10th	Night	12% 6% 26% 37% 17% 1	390
	11th to 20th	Night	11% 7% 25% 38% 17% 1	388
	21st to end	Night	13% 8% 27% 38% 13% 1	438
August	1st to 10th	Night	14% 3 24% 38% 19% 2	597
	11th to 20th	Night	14% 7% 19% 37% 21% 2	722
	21st to end	Night	14% 9% 24% 31% 20% 1	880
September	1st to 10th	Night	17% 9% 28% 28% 17% 2	800
	11th to 20th	Night	13% 9% 27% 27% 20% 6%	800
	21st to end	Night	21% 12% 23% 28% 14% 2	800
October	1st to 10th	Night	23% 14% 22% 24% 16% 2	800
	11th to 20th	Night	21% 18% 29% 25% 7%	800
	21st to end	Night	25% 21% 31% 17% 5%	880
November	1st to 10th	Night	20% 23% 30% 20% 6% 1	820
	11th to 20th	Night	27% 25% 26% 15% 5% 1	840
	21st to end	Night	24% 25% 31% 15% 5%	840
December	1st to 10th	Night	27% 26% 30% 13% 4	840
	11th to 20th	Night	29% 25% 29% 15% 1	840
	21st to end	Night	28% 28% 29% 13% 3	924

Page generated at 2026-03-15 02:23:54. Version ac07

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