Camden
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Camden clear sky chart from 2005-11-06 to 2024-01-12.

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	18% 7% 3 5% 5% 3 4 4 5% 7% 39%	74571
	Night	18% 8% 3 5% 5% 3 4 4 5% 6% 39%	75135
Transparency	Day	45% 6% 11% 22% 14% 2	74279
	Night	46% 5% 11% 21% 15% 2	74962
Seeing	Day	22% 15% 32% 22% 8% 2	14474
	Night	22% 13% 31% 25% 8% 1	23067

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	15% 8% 4 6% 6% 3 3 3 4 6% 41%	1517
	11th to 20th	Day	20% 9% 3 6% 4 3 4 3 4 7% 38%	1454
	21st to end	Day	14% 10% 4 7% 5% 3 3 4 4 5% 41%	1611
February	1st to 10th	Day	18% 10% 3 6% 4 3 5% 4 5% 5% 36%	1620
	11th to 20th	Day	15% 9% 2 6% 5% 3 5% 5% 5% 6% 38%	1691
	21st to end	Day	15% 10% 4 7% 6% 2 4 5% 5% 6% 35%	1480
March	1st to 10th	Day	16% 10% 2 5% 6% 3 6% 4 5% 7% 36%	1798
	11th to 20th	Day	18% 6% 3 5% 5% 3 4 4 5% 5% 43%	1980
	21st to end	Day	18% 10% 3 4 4 3 5% 4 4 6% 40%	2178
April	1st to 10th	Day	20% 11% 3 6% 4 3 4 4 4 6% 34%	2150
	11th to 20th	Day	19% 8% 3 6% 5% 3 4 4 5% 7% 38%	2272
	21st to end	Day	23% 8% 3 6% 5% 2 4 5% 4 7% 33%	2340
May	1st to 10th	Day	24% 8% 4 5% 5% 3 5% 4 4 6% 33%	2340
	11th to 20th	Day	21% 7% 3 5% 5% 3 4 4 5% 5% 39%	2301
	21st to end	Day	18% 7% 3 4 4 3 4 5% 6% 8% 36%	2704
June	1st to 10th	Day	22% 7% 3 6% 5% 3 5% 5% 5% 7% 32%	2700
	11th to 20th	Day	19% 7% 3 5% 5% 3 4 4 6% 7% 38%	2700
	21st to end	Day	25% 6% 3 5% 4 3 5% 5% 6% 7% 30%	2695
July	1st to 10th	Day	17% 6% 3 4 4 3 5% 5% 6% 8% 39%	2520
	11th to 20th	Day	14% 6% 3 6% 5% 4 5% 5% 6% 9% 38%	2520
	21st to end	Day	14% 5% 3 4 5% 3 6% 6% 6% 10% 36%	2706
August	1st to 10th	Day	14% 6% 2 5% 5% 3 5% 6% 7% 9% 39%	2327
	11th to 20th	Day	14% 6% 2 6% 6% 4 4 5% 6% 8% 38%	2304
	21st to end	Day	13% 5% 2 4 4 3 5% 5% 6% 9% 44%	2543
September	1st to 10th	Day	10% 6% 2 4 5% 3 4 4 5% 8% 48%	2080
	11th to 20th	Day	13% 4 2 4 4 2 3 3 4 6% 54%	1980
	21st to end	Day	18% 6% 2 3 4 3 3 4 5% 7% 45%	1980
October	1st to 10th	Day	16% 6% 4 5% 6% 3 5% 4 4 6% 42%	1944
	11th to 20th	Day	20% 5% 2 4 5% 3 4 4 4 6% 42%	1779
	21st to end	Day	23% 9% 2 5% 4 2 3 5% 3 6% 37%	1782
November	1st to 10th	Day	17% 6% 3 5% 4 3 4 3 4 7% 44%	1671
	11th to 20th	Day	21% 5% 2 4 3 3 4 5% 4 7% 43%	1710
	21st to end	Day	20% 9% 2 4 3 2 3 4 3 5% 43%	1541
December	1st to 10th	Day	22% 9% 3 5% 6% 2 4 4 4 6% 36%	1421
	11th to 20th	Day	23% 9% 3 4 4 3 4 3 4 5% 40%	1668
	21st to end	Day	26% 10% 2 4 5% 3 4 4 5% 5% 32%	2564
January	1st to 10th	Night	16% 8% 3 6% 5% 3 4 4 5% 6% 39%	2649
	11th to 20th	Night	17% 12% 4 7% 6% 3 4 4 4 6% 33%	2546
	21st to end	Night	12% 10% 4 6% 5% 3 5% 5% 5% 6% 40%	2744
February	1st to 10th	Night	17% 9% 4 5% 5% 4 6% 5% 4 6% 34%	2340
	11th to 20th	Night	15% 8% 4 7% 5% 3 4 4 4 6% 38%	2151
	21st to end	Night	14% 9% 4 6% 5% 3 4 4 4 6% 41%	1776
March	1st to 10th	Night	15% 12% 3 6% 5% 3 4 5% 4 5% 39%	2147
	11th to 20th	Night	18% 7% 3 6% 6% 2 5% 5% 6% 6% 35%	1979
	21st to end	Night	18% 7% 3 6% 5% 2 4 4 4 5% 41%	2178
April	1st to 10th	Night	23% 9% 3 5% 5% 3 4 4 4 6% 34%	1805
	11th to 20th	Night	19% 7% 2 5% 5% 3 4 4 5% 9% 36%	1635
	21st to end	Night	24% 9% 4 6% 4 3 4 4 4 6% 33%	1620
May	1st to 10th	Night	22% 9% 3 6% 5% 2 5% 5% 5% 7% 30%	1620
	11th to 20th	Night	22% 7% 3 6% 4 3 6% 5% 6% 7% 31%	1593
	21st to end	Night	19% 8% 3 6% 5% 3 4 4 4 7% 34%	1580
June	1st to 10th	Night	23% 8% 3 6% 5% 3 5% 5% 6% 6% 30%	1260
	11th to 20th	Night	17% 8% 3 6% 5% 2 4 5% 5% 7% 37%	1260
	21st to end	Night	23% 9% 2 6% 4 3 4 5% 5% 7% 31%	1260
July	1st to 10th	Night	17% 8% 3 4 4 3 5% 6% 6% 9% 36%	1439
	11th to 20th	Night	17% 5% 3 5% 5% 4 5% 5% 6% 8% 36%	1440
	21st to end	Night	16% 7% 3 5% 4 4 5% 5% 5% 8% 37%	1592
August	1st to 10th	Night	14% 7% 3 4 4 4 5% 4 5% 9% 41%	1612
	11th to 20th	Night	14% 9% 3 5% 5% 4 5% 5% 5% 9% 37%	1596
	21st to end	Night	14% 5% 3 4 4 3 4 5% 4 7% 47%	1810
September	1st to 10th	Night	13% 5% 2 4 4 3 4 4 5% 7% 49%	1880
	11th to 20th	Night	15% 7% 2 4 2 1 3 3 3 7% 52%	1980
	21st to end	Night	16% 5% 2 5% 4 2 4 4 4 6% 47%	1980
October	1st to 10th	Night	18% 6% 3 5% 4 3 5% 4 4 7% 40%	2015
	11th to 20th	Night	18% 5% 2 5% 4 3 4 4 5% 6% 43%	2178
	21st to end	Night	25% 7% 2 4 5% 3 4 3 4 6% 37%	2574
November	1st to 10th	Night	18% 6% 2 5% 5% 2 3 5% 4 6% 44%	2407
	11th to 20th	Night	18% 6% 2 4 5% 3 5% 4 4 6% 44%	2470
	21st to end	Night	18% 6% 3 4 5% 2 4 4 5% 7% 42%	2636
December	1st to 10th	Night	22% 9% 3 6% 5% 3 3 4 5% 6% 35%	2758
	11th to 20th	Night	22% 8% 2 4 4 2 3 4 4 5% 41%	3531
	21st to end	Night	24% 9% 2 5% 4 2 4 4 4 5% 36%	5094

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	45% 5% 9% 23% 16% 2	1518
	11th to 20th	Day	50% 5% 12% 20% 12% 2	1454
	21st to end	Day	45% 2 11% 22% 17% 2	1611
February	1st to 10th	Day	51% 4 11% 18% 15% 2	1620
	11th to 20th	Day	46% 5% 12% 19% 15% 2	1700
	21st to end	Day	49% 5% 9% 20% 12% 5%	1480
March	1st to 10th	Day	47% 5% 12% 18% 14% 4	1801
	11th to 20th	Day	43% 4 10% 21% 17% 5%	1980
	21st to end	Day	45% 5% 9% 17% 17% 6%	2178
April	1st to 10th	Day	51% 4 9% 17% 15% 4	2150
	11th to 20th	Day	45% 5% 10% 22% 16% 2	2272
	21st to end	Day	51% 5% 8% 18% 14% 4	2340
May	1st to 10th	Day	52% 5% 8% 20% 13% 3	2340
	11th to 20th	Day	46% 5% 9% 22% 15% 2	2305
	21st to end	Day	47% 7% 13% 21% 11% 2	2704
June	1st to 10th	Day	51% 7% 11% 21% 9% 1	2700
	11th to 20th	Day	44% 7% 11% 20% 16% 2	2700
	21st to end	Day	53% 8% 10% 18% 10% 1	2695
July	1st to 10th	Day	42% 7% 14% 24% 13%	2450
	11th to 20th	Day	42% 8% 14% 24% 11% 1	2445
	21st to end	Day	42% 8% 14% 24% 11% 1	2555
August	1st to 10th	Day	39% 10% 14% 28% 9%	2314
	11th to 20th	Day	41% 8% 15% 23% 13%	2304
	21st to end	Day	35% 7% 13% 26% 18% 1	2543
September	1st to 10th	Day	34% 7% 14% 27% 18% 1	2080
	11th to 20th	Day	33% 5% 11% 27% 21% 3	1980
	21st to end	Day	41% 5% 8% 27% 17% 1	1980
October	1st to 10th	Day	44% 6% 10% 23% 15% 2	1944
	11th to 20th	Day	43% 5% 13% 28% 12% 1	1779
	21st to end	Day	49% 4 11% 20% 15% 2	1782
November	1st to 10th	Day	41% 4 13% 24% 16% 2	1671
	11th to 20th	Day	42% 4 10% 21% 20% 3	1710
	21st to end	Day	45% 4 16% 21% 13% 1	1541
December	1st to 10th	Day	51% 4 10% 22% 12% 1	1421
	11th to 20th	Day	48% 4 10% 20% 14% 4	1668
	21st to end	Day	54% 7% 11% 17% 9% 2	2564
January	1st to 10th	Night	46% 4 12% 23% 13% 2	2649
	11th to 20th	Night	54% 5% 11% 18% 10% 2	2546
	21st to end	Night	44% 4 11% 22% 17% 2	2744
February	1st to 10th	Night	51% 4 11% 18% 13% 3	2340
	11th to 20th	Night	48% 4 9% 20% 16% 3	2153
	21st to end	Night	45% 4 10% 21% 15% 5%	1776
March	1st to 10th	Night	47% 4 9% 20% 16% 3	2157
	11th to 20th	Night	48% 5% 12% 16% 15% 4	1980
	21st to end	Night	45% 3 9% 18% 20% 4	2178
April	1st to 10th	Night	51% 4 8% 14% 18% 4	1805
	11th to 20th	Night	47% 4 7% 23% 17% 1	1635
	21st to end	Night	53% 5% 10% 16% 13% 4	1620
May	1st to 10th	Night	53% 6% 9% 17% 13% 1	1620
	11th to 20th	Night	52% 6% 9% 18% 12% 3	1594
	21st to end	Night	51% 6% 9% 18% 14% 1	1581
June	1st to 10th	Night	53% 8% 9% 20% 8% 1	1260
	11th to 20th	Night	48% 6% 13% 19% 13% 2	1260
	21st to end	Night	54% 6% 10% 19% 10% 2	1260
July	1st to 10th	Night	44% 8% 14% 21% 12% 1	1399
	11th to 20th	Night	46% 6% 14% 23% 11% 1	1392
	21st to end	Night	44% 6% 15% 24% 9% 2	1503
August	1st to 10th	Night	43% 7% 14% 26% 10% 1	1600
	11th to 20th	Night	45% 7% 14% 20% 13%	1596
	21st to end	Night	38% 6% 10% 26% 19% 1	1810
September	1st to 10th	Night	36% 6% 13% 28% 17% 1	1880
	11th to 20th	Night	36% 4 11% 27% 21% 2	1980
	21st to end	Night	38% 5% 9% 29% 17% 2	1980
October	1st to 10th	Night	44% 5% 11% 24% 14% 2	2015
	11th to 20th	Night	41% 5% 12% 28% 13% 1	2178
	21st to end	Night	50% 5% 10% 20% 14% 1	2574
November	1st to 10th	Night	42% 5% 11% 24% 16% 1	2407
	11th to 20th	Night	43% 4 10% 23% 18% 2	2470
	21st to end	Night	44% 5% 13% 20% 16% 2	2636
December	1st to 10th	Night	52% 5% 9% 21% 13% 1	2758
	11th to 20th	Night	46% 4 11% 21% 18% 1	3532
	21st to end	Night	50% 6% 11% 18% 13% 1	5094

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	25% 22% 30% 18% 5%	180
	11th to 20th	Day	25% 26% 27% 17% 4 1	164
	21st to end	Day	19% 22% 35% 19% 4	203
February	1st to 10th	Day	27% 21% 34% 16% 3	340
	11th to 20th	Day	25% 24% 35% 14% 2	390
	21st to end	Day	22% 21% 36% 18% 3	346
March	1st to 10th	Day	23% 22% 37% 15% 2	420
	11th to 20th	Day	21% 22% 37% 15% 3 1	420
	21st to end	Day	25% 24% 29% 14% 6% 2	462
April	1st to 10th	Day	30% 21% 31% 13% 4 1	420
	11th to 20th	Day	25% 22% 31% 17% 5% 1	412
	21st to end	Day	27% 16% 38% 13% 6% 1	420
May	1st to 10th	Day	27% 20% 31% 16% 4 1	423
	11th to 20th	Day	17% 17% 39% 21% 5% 1	447
	21st to end	Day	19% 15% 38% 22% 5% 1	493
June	1st to 10th	Day	23% 11% 30% 24% 10% 1	630
	11th to 20th	Day	20% 10% 33% 24% 12% 2	630
	21st to end	Day	25% 8% 28% 27% 10% 1	625
July	1st to 10th	Day	21% 7% 34% 27% 9% 2	445
	11th to 20th	Day	16% 6% 35% 29% 12% 3	444
	21st to end	Day	15% 5% 37% 30% 11% 2	488
August	1st to 10th	Day	14% 6% 30% 35% 14% 1	446
	11th to 20th	Day	18% 6% 27% 34% 12% 3	439
	21st to end	Day	16% 8% 30% 29% 13% 3	495
September	1st to 10th	Day	14% 6% 32% 30% 16% 2	450
	11th to 20th	Day	17% 10% 33% 21% 14% 5%	450
	21st to end	Day	17% 12% 32% 24% 10% 5%	450
October	1st to 10th	Day	19% 14% 25% 28% 11% 3	432
	11th to 20th	Day	19% 16% 32% 22% 8% 3	360
	21st to end	Day	30% 13% 30% 22% 5% 1	396
November	1st to 10th	Day	19% 19% 28% 25% 7% 2	365
	11th to 20th	Day	26% 18% 31% 20% 4 1	370
	21st to end	Day	25% 22% 29% 17% 6%	370
December	1st to 10th	Day	23% 17% 37% 17% 5% 1	271
	11th to 20th	Day	32% 25% 32% 9% 1 1	180
	21st to end	Day	28% 25% 30% 12% 5%	198
January	1st to 10th	Night	21% 22% 35% 20% 3	760
	11th to 20th	Night	26% 20% 35% 15% 4	728
	21st to end	Night	18% 22% 40% 18% 2	792
February	1st to 10th	Night	24% 20% 35% 19% 2	720
	11th to 20th	Night	21% 21% 38% 17% 3	703
	21st to end	Night	21% 17% 38% 20% 4	592
March	1st to 10th	Night	23% 18% 38% 19% 2	720
	11th to 20th	Night	22% 16% 34% 22% 6%	720
	21st to end	Night	22% 17% 33% 22% 6% 1	792
April	1st to 10th	Night	28% 15% 34% 19% 4 1	720
	11th to 20th	Night	23% 12% 32% 28% 5%	571
	21st to end	Night	30% 10% 29% 24% 6% 1	540
May	1st to 10th	Night	26% 8% 31% 27% 8% 1	540
	11th to 20th	Night	24% 7% 37% 27% 5%	532
	21st to end	Night	23% 7% 27% 34% 9% 1	432
June	1st to 10th	Night	27% 6% 24% 31% 10% 1	360
	11th to 20th	Night	19% 6% 24% 36% 14% 1	360
	21st to end	Night	25% 5% 24% 36% 9%	360
July	1st to 10th	Night	21% 4 20% 40% 15%	350
	11th to 20th	Night	20% 4 20% 39% 17% 1	348
	21st to end	Night	18% 3 22% 41% 16% 1	412
August	1st to 10th	Night	16% 4 22% 42% 16% 1	538
	11th to 20th	Night	16% 4 22% 40% 16% 2	532
	21st to end	Night	15% 5% 22% 38% 18% 2	622
September	1st to 10th	Night	14% 5% 28% 35% 17% 1	720
	11th to 20th	Night	19% 7% 27% 27% 15% 5%	720
	21st to end	Night	18% 8% 30% 28% 15% 2	720
October	1st to 10th	Night	22% 8% 25% 28% 15% 1	720
	11th to 20th	Night	20% 11% 32% 25% 10% 2	720
	21st to end	Night	29% 13% 30% 23% 5%	792
November	1st to 10th	Night	24% 11% 31% 26% 7% 2	740
	11th to 20th	Night	21% 16% 33% 22% 7% 1	760
	21st to end	Night	21% 20% 33% 20% 6%	838
December	1st to 10th	Night	27% 15% 37% 15% 5%	850
	11th to 20th	Night	24% 22% 33% 18% 3	850
	21st to end	Night	27% 20% 33% 17% 3	893

Page generated at 2024-01-09 16:24:28. Version ac07

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