Camden Lake
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Camden Lake clear sky chart from 2005-11-06 to 2026-06-16.

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% 3 8% 5% 4 4 4 5% 7% 34%	138169
	Night	17% 11% 4 8% 5% 4 4 4 5% 6% 33%	133836
Transparency	Day	50% 5% 12% 21% 11% 1	141687
	Night	51% 5% 11% 20% 11% 1	138406
Seeing	Day	23% 16% 31% 19% 8% 3	16480
	Night	22% 13% 31% 24% 9% 1	25715

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% 14% 4 10% 6% 4 5% 4 5% 6% 28%	4661
	11th to 20th	Day	12% 21% 8% 14% 6% 5% 4 3 4 4 18%	4650
	21st to end	Day	11% 16% 7% 15% 7% 7% 5% 3 4 4 21%	5642
February	1st to 10th	Day	15% 17% 4 11% 6% 5% 4 4 6% 6% 24%	1890
	11th to 20th	Day	12% 16% 4 11% 7% 5% 5% 3 4 5% 27%	1843
	21st to end	Day	19% 14% 5% 9% 7% 6% 4 3 4 4 24%	1699
March	1st to 10th	Day	18% 13% 4 9% 5% 4 3 2 4 5% 31%	4753
	11th to 20th	Day	12% 13% 4 9% 5% 5% 5% 4 5% 6% 33%	5090
	21st to end	Day	20% 11% 3 7% 4 3 3 3 4 5% 38%	5787
April	1st to 10th	Day	20% 14% 3 7% 5% 4 4 3 3 5% 32%	2520
	11th to 20th	Day	22% 10% 2 5% 4 4 4 3 4 5% 37%	2494
	21st to end	Day	21% 10% 3 8% 5% 4 4 3 5% 5% 33%	2649
May	1st to 10th	Day	22% 9% 2 7% 5% 5% 4 4 5% 6% 30%	8154
	11th to 20th	Day	16% 8% 3 8% 5% 4 4 3 5% 7% 36%	8221
	21st to end	Day	20% 7% 2 6% 4 4 4 4 6% 7% 36%	9060
June	1st to 10th	Day	19% 7% 3 7% 5% 5% 4 5% 5% 6% 34%	2940
	11th to 20th	Day	15% 5% 2 6% 4 4 5% 4 6% 8% 39%	2870
	21st to end	Day	17% 8% 2 6% 5% 4 5% 5% 6% 8% 35%	2800
July	1st to 10th	Day	12% 6% 2 7% 5% 5% 5% 4 6% 10% 39%	6360
	11th to 20th	Day	12% 4 2 5% 4 5% 5% 4 6% 9% 44%	6360
	21st to end	Day	10% 4 2 6% 4 4 5% 4 6% 9% 46%	6926
August	1st to 10th	Day	17% 7% 3 6% 4 4 4 4 6% 8% 38%	4305
	11th to 20th	Day	17% 5% 2 6% 4 4 4 3 6% 8% 39%	4174
	21st to end	Day	14% 5% 2 6% 4 4 4 4 7% 9% 42%	4312
September	1st to 10th	Day	13% 6% 2 5% 4 5% 4 3 5% 8% 44%	2400
	11th to 20th	Day	11% 5% 2 5% 4 3 3 3 4 8% 51%	2400
	21st to end	Day	18% 6% 3 6% 4 4 4 4 5% 8% 38%	2111
October	1st to 10th	Day	20% 7% 2 6% 5% 4 4 3 4 6% 38%	2000
	11th to 20th	Day	21% 8% 2 8% 5% 4 5% 3 5% 8% 31%	2000
	21st to end	Day	26% 10% 3 7% 4 4 4 4 4 6% 28%	2113
November	1st to 10th	Day	17% 9% 3 7% 5% 5% 5% 4 5% 7% 34%	1831
	11th to 20th	Day	16% 13% 3 8% 5% 4 5% 4 5% 4 32%	1680
	21st to end	Day	21% 15% 3 9% 5% 4 4 4 5% 6% 25%	1680
December	1st to 10th	Day	21% 16% 4 10% 5% 5% 5% 3 5% 6% 21%	2680
	11th to 20th	Day	18% 21% 4 9% 4 4 4 3 4 4 24%	3066
	21st to end	Day	23% 15% 4 10% 5% 4 3 2 3 5% 25%	4048
January	1st to 10th	Night	15% 14% 6% 12% 6% 5% 5% 3 5% 6% 24%	8234
	11th to 20th	Night	13% 18% 7% 15% 8% 6% 5% 4 4 4 17%	8235
	21st to end	Night	14% 13% 6% 12% 6% 6% 5% 4 4 5% 25%	8525
February	1st to 10th	Night	15% 13% 5% 10% 6% 5% 5% 4 5% 6% 26%	2730
	11th to 20th	Night	14% 14% 5% 11% 5% 5% 4 3 5% 5% 29%	2663
	21st to end	Night	16% 14% 4 7% 5% 5% 4 3 6% 6% 29%	2105
March	1st to 10th	Night	19% 13% 3 9% 5% 4 5% 3 4 5% 30%	5304
	11th to 20th	Night	14% 12% 3 7% 5% 4 5% 4 6% 8% 32%	5089
	21st to end	Night	20% 9% 3 7% 4 3 3 2 5% 6% 37%	5386
April	1st to 10th	Night	22% 10% 3 7% 4 3 3 3 5% 6% 33%	2100
	11th to 20th	Night	20% 9% 3 6% 5% 3 4 3 5% 5% 37%	2075
	21st to end	Night	19% 9% 2 7% 5% 4 4 3 6% 6% 35%	1989
May	1st to 10th	Night	25% 9% 3 7% 5% 4 5% 3 5% 7% 28%	4744
	11th to 20th	Night	15% 8% 3 7% 4 4 4 3 5% 6% 40%	4639
	21st to end	Night	19% 6% 2 5% 4 4 4 4 6% 8% 38%	5114
June	1st to 10th	Night	16% 6% 2 7% 5% 6% 5% 4 6% 8% 35%	1680
	11th to 20th	Night	12% 6% 2 6% 4 4 5% 4 6% 8% 43%	1640
	21st to end	Night	16% 6% 2 7% 5% 5% 4 5% 7% 6% 38%	1600
July	1st to 10th	Night	12% 5% 2 7% 5% 5% 4 4 7% 9% 39%	3600
	11th to 20th	Night	13% 5% 2 5% 4 4 4 4 5% 7% 47%	3600
	21st to end	Night	10% 5% 1 5% 3 4 4 4 6% 8% 50%	3926
August	1st to 10th	Night	12% 6% 2 6% 4 4 4 3 5% 8% 46%	2840
	11th to 20th	Night	14% 6% 2 5% 3 4 4 3 6% 7% 47%	2875
	21st to end	Night	10% 4 3 5% 5% 5% 5% 5% 7% 9% 43%	3552
September	1st to 10th	Night	12% 5% 2 5% 4 3 4 3 5% 8% 48%	2000
	11th to 20th	Night	12% 4 2 5% 3 3 4 3 5% 6% 53%	2000
	21st to end	Night	18% 5% 2 6% 3 5% 4 4 5% 6% 42%	2285
October	1st to 10th	Night	16% 7% 2 6% 5% 4 4 4 5% 6% 41%	2400
	11th to 20th	Night	20% 7% 3 7% 5% 5% 4 4 5% 6% 33%	2400
	21st to end	Night	22% 10% 3 7% 5% 3 4 4 5% 6% 31%	2725
November	1st to 10th	Night	18% 10% 3 7% 3 4 4 3 4 6% 38%	2683
	11th to 20th	Night	19% 10% 3 7% 4 5% 4 4 5% 6% 33%	2940
	21st to end	Night	21% 12% 3 8% 5% 5% 5% 4 5% 6% 27%	2940
December	1st to 10th	Night	20% 15% 4 9% 6% 5% 5% 4 5% 5% 21%	4720
	11th to 20th	Night	22% 16% 4 8% 4 4 4 3 4 5% 26%	5348
	21st to end	Night	27% 16% 4 10% 4 4 3 3 4 5% 22%	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	57% 5% 11% 19% 6% 1	4662
	11th to 20th	Day	71% 4 8% 9% 7% 1	4680
	21st to end	Day	68% 4 8% 10% 10% 1	5642
February	1st to 10th	Day	61% 5% 10% 17% 6% 1	1890
	11th to 20th	Day	60% 5% 9% 16% 9% 1	1852
	21st to end	Day	64% 4 10% 12% 9% 1	1699
March	1st to 10th	Day	57% 4 10% 14% 15% 2	4756
	11th to 20th	Day	53% 4 18% 14% 10% 2	5090
	21st to end	Day	50% 4 6% 21% 17% 3	5787
April	1st to 10th	Day	56% 4 7% 18% 12% 3	2520
	11th to 20th	Day	50% 4 7% 21% 15% 2	2494
	21st to end	Day	54% 4 9% 17% 13% 3	2649
May	1st to 10th	Day	55% 4 9% 19% 11% 2	8165
	11th to 20th	Day	47% 6% 12% 21% 13% 1	8225
	21st to end	Day	47% 5% 12% 24% 11% 1	9061
June	1st to 10th	Day	48% 8% 10% 19% 14% 1	2940
	11th to 20th	Day	41% 6% 13% 26% 13% 2	2870
	21st to end	Day	45% 8% 14% 21% 12% 1	2800
July	1st to 10th	Day	41% 4 15% 27% 12%	6290
	11th to 20th	Day	36% 4 16% 29% 15%	6285
	21st to end	Day	34% 5% 14% 35% 10%	6728
August	1st to 10th	Day	44% 6% 15% 24% 11% 1	4291
	11th to 20th	Day	42% 6% 14% 28% 9% 1	4213
	21st to end	Day	38% 5% 14% 31% 10% 1	4312
September	1st to 10th	Day	37% 7% 15% 28% 12% 1	2400
	11th to 20th	Day	33% 5% 13% 31% 16% 1	2400
	21st to end	Day	44% 7% 12% 26% 10%	2111
October	1st to 10th	Day	41% 5% 12% 33% 10%	3260
	11th to 20th	Day	45% 5% 15% 26% 9% 1	3240
	21st to end	Day	51% 4 14% 22% 8%	3390
November	1st to 10th	Day	48% 7% 14% 22% 9% 1	1831
	11th to 20th	Day	54% 6% 11% 18% 11% 1	1680
	21st to end	Day	60% 7% 12% 13% 8%	1680
December	1st to 10th	Day	65% 4 17% 10% 4	2680
	11th to 20th	Day	64% 4 10% 13% 7%	3066
	21st to end	Day	64% 4 8% 18% 6%	4048
January	1st to 10th	Night	62% 5% 12% 14% 7%	8234
	11th to 20th	Night	69% 6% 8% 10% 6%	8280
	21st to end	Night	61% 4 8% 13% 13% 1	8525
February	1st to 10th	Night	59% 5% 11% 18% 6% 1	2730
	11th to 20th	Night	57% 4 9% 20% 9% 1	2665
	21st to end	Night	55% 5% 11% 18% 9% 1	2105
March	1st to 10th	Night	57% 4 6% 18% 11% 4	5314
	11th to 20th	Night	49% 5% 17% 18% 9% 2	5090
	21st to end	Night	48% 4 8% 22% 16% 2	5386
April	1st to 10th	Night	52% 4 8% 21% 14% 2	2100
	11th to 20th	Night	49% 5% 9% 20% 16% 1	2075
	21st to end	Night	49% 6% 8% 18% 15% 3	1989
May	1st to 10th	Night	56% 3 9% 17% 11% 3	4750
	11th to 20th	Night	43% 6% 14% 22% 14% 1	4640
	21st to end	Night	44% 5% 13% 21% 16% 1	5115
June	1st to 10th	Night	45% 6% 12% 21% 14% 1	1680
	11th to 20th	Night	38% 6% 13% 21% 19% 2	1640
	21st to end	Night	43% 6% 15% 22% 12% 1	1600
July	1st to 10th	Night	41% 4 17% 20% 17% 1	3560
	11th to 20th	Night	36% 5% 13% 33% 13%	3552
	21st to end	Night	33% 5% 14% 34% 13% 1	3809
August	1st to 10th	Night	38% 5% 15% 27% 14% 1	2830
	11th to 20th	Night	37% 5% 16% 31% 11% 1	2902
	21st to end	Night	36% 6% 15% 31% 11% 1	3552
September	1st to 10th	Night	35% 6% 15% 30% 14% 1	2000
	11th to 20th	Night	31% 6% 14% 35% 15% 1	2000
	21st to end	Night	42% 6% 11% 28% 13% 1	2285
October	1st to 10th	Night	37% 5% 11% 28% 19% 1	3920
	11th to 20th	Night	43% 4 15% 28% 10%	3899
	21st to end	Night	48% 5% 13% 25% 9%	4398
November	1st to 10th	Night	47% 6% 13% 23% 11% 1	2683
	11th to 20th	Night	50% 6% 12% 20% 10% 2	2940
	21st to end	Night	57% 7% 13% 17% 6%	2940
December	1st to 10th	Night	64% 4 14% 15% 4	4720
	11th to 20th	Night	61% 5% 10% 15% 9%	5348
	21st to end	Night	66% 5% 8% 11% 10%	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	28% 18% 38% 13% 4	220
	11th to 20th	Day	30% 21% 32% 15% 3	220
	21st to end	Day	26% 22% 33% 15% 3	338
February	1st to 10th	Day	29% 28% 29% 12% 2	330
	11th to 20th	Day	28% 29% 36% 7%	330
	21st to end	Day	33% 22% 35% 8% 2	415
March	1st to 10th	Day	26% 21% 33% 15% 4	540
	11th to 20th	Day	30% 22% 29% 14% 4	540
	21st to end	Day	35% 19% 27% 13% 5% 1	594
April	1st to 10th	Day	31% 22% 31% 11% 4	540
	11th to 20th	Day	34% 22% 21% 13% 7% 2	532
	21st to end	Day	28% 21% 33% 12% 5% 2	540
May	1st to 10th	Day	25% 19% 29% 19% 7% 2	543
	11th to 20th	Day	20% 14% 38% 17% 8% 2	567
	21st to end	Day	19% 15% 34% 20% 9% 2	617
June	1st to 10th	Day	21% 14% 34% 22% 8% 2	570
	11th to 20th	Day	16% 15% 35% 21% 11% 2	550
	21st to end	Day	21% 14% 32% 22% 10% 2	530
July	1st to 10th	Day	12% 10% 31% 30% 14% 3	525
	11th to 20th	Day	15% 9% 30% 28% 14% 4	524
	21st to end	Day	13% 7% 38% 27% 11% 4	576
August	1st to 10th	Day	15% 7% 29% 29% 16% 5%	526
	11th to 20th	Day	14% 6% 28% 29% 16% 7%	519
	21st to end	Day	13% 11% 32% 25% 11% 8%	583
September	1st to 10th	Day	14% 13% 31% 25% 12% 7%	530
	11th to 20th	Day	11% 8% 25% 25% 20% 12%	530
	21st to end	Day	18% 11% 30% 24% 12% 4	530
October	1st to 10th	Day	23% 14% 28% 17% 14% 5%	530
	11th to 20th	Day	23% 23% 30% 18% 4 2	530
	21st to end	Day	30% 18% 28% 19% 4	534
November	1st to 10th	Day	27% 18% 28% 19% 8%	405
	11th to 20th	Day	29% 18% 35% 12% 6%	220
	21st to end	Day	26% 22% 38% 10% 3 1	220
December	1st to 10th	Day	29% 24% 33% 10% 3	220
	11th to 20th	Day	36% 23% 27% 11% 3	220
	21st to end	Day	35% 20% 31% 11% 3	242
January	1st to 10th	Night	27% 18% 34% 18% 3	840
	11th to 20th	Night	30% 16% 30% 19% 4	840
	21st to end	Night	21% 16% 36% 22% 4	924
February	1st to 10th	Night	24% 19% 34% 20% 2	840
	11th to 20th	Night	24% 17% 38% 18% 3	823
	21st to end	Night	25% 19% 35% 18% 3	692
March	1st to 10th	Night	24% 17% 36% 20% 3	840
	11th to 20th	Night	26% 19% 31% 20% 3 1	840
	21st to end	Night	24% 16% 34% 19% 6% 1	924
April	1st to 10th	Night	27% 16% 33% 21% 3	840
	11th to 20th	Night	24% 20% 31% 19% 7% 1	831
	21st to end	Night	25% 12% 30% 24% 9%	729
May	1st to 10th	Night	27% 8% 27% 27% 11% 1	452
	11th to 20th	Night	15% 9% 36% 32% 8%	414
	21st to end	Night	13% 9% 38% 28% 11% 1	455
June	1st to 10th	Night	15% 7% 35% 32% 10%	420
	11th to 20th	Night	14% 8% 35% 31% 12% 1	410
	21st to end	Night	18% 7% 27% 37% 12%	400
July	1st to 10th	Night	8% 6% 29% 39% 18%	390
	11th to 20th	Night	12% 5% 27% 36% 19% 1	388
	21st to end	Night	13% 3 30% 39% 14%	438
August	1st to 10th	Night	11% 5% 25% 35% 24% 1	548
	11th to 20th	Night	12% 5% 22% 34% 23% 3	594
	21st to end	Night	11% 6% 31% 33% 17% 2	859
September	1st to 10th	Night	14% 7% 30% 30% 17% 3	800
	11th to 20th	Night	13% 6% 22% 27% 27% 5%	800
	21st to end	Night	20% 10% 21% 29% 18% 2	800
October	1st to 10th	Night	20% 12% 27% 22% 17% 2	800
	11th to 20th	Night	25% 14% 30% 23% 8% 1	800
	21st to end	Night	26% 15% 30% 23% 6%	880
November	1st to 10th	Night	26% 13% 29% 23% 7%	820
	11th to 20th	Night	26% 15% 34% 18% 7%	840
	21st to end	Night	31% 18% 28% 18% 6%	840
December	1st to 10th	Night	30% 19% 29% 18% 3	840
	11th to 20th	Night	28% 20% 34% 15% 2 1	840
	21st to end	Night	34% 16% 30% 16% 2	924

Page generated at 2026-06-13 02:31:45. Version ac07

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