Albany
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Albany clear sky chart from 2005-11-06 to 2024-11-02.

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% 8% 3 7% 5% 4 4 3 4 5% 39%	101532
	Night	20% 9% 3 7% 4 4 4 3 4 5% 37%	97607
Transparency	Day	45% 8% 12% 17% 13% 5%	101277
	Night	48% 8% 13% 17% 11% 4	97451
Seeing	Day	17% 9% 20% 27% 21% 6%	14724
	Night	20% 6% 18% 33% 21% 2	23650

By Month

Percentage Cloud Cover SW (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	37% 15% 6% 13% 5% 5% 4 2 3 3 7%	2539
	11th to 20th	Day	40% 12% 4 9% 5% 4 4 3 3 3 14%	2541
	21st to end	Day	33% 12% 5% 12% 6% 5% 5% 3 4 5% 12%	3146
February	1st to 10th	Day	28% 13% 5% 10% 6% 5% 5% 4 5% 5% 14%	1710
	11th to 20th	Day	27% 12% 5% 9% 7% 5% 4 3 5% 5% 18%	1665
	21st to end	Day	29% 15% 4 11% 5% 4 4 3 3 5% 18%	1484
March	1st to 10th	Day	21% 13% 4 11% 8% 6% 6% 4 6% 6% 16%	3340
	11th to 20th	Day	19% 8% 3 8% 5% 5% 4 3 4 5% 34%	3490
	21st to end	Day	24% 13% 4 10% 7% 7% 5% 4 5% 5% 17%	3876
April	1st to 10th	Day	25% 13% 4 9% 6% 5% 5% 3 5% 6% 18%	2280
	11th to 20th	Day	23% 11% 4 7% 5% 4 5% 4 5% 6% 26%	2249
	21st to end	Day	21% 9% 3 8% 6% 5% 5% 3 6% 7% 28%	2464
May	1st to 10th	Day	20% 7% 3 8% 5% 4 5% 3 5% 6% 34%	4282
	11th to 20th	Day	11% 5% 1 4 4 3 3 3 5% 6% 54%	4377
	21st to end	Day	16% 7% 2 7% 6% 6% 6% 6% 7% 8% 31%	4813
June	1st to 10th	Day	19% 8% 3 7% 4 4 4 3 5% 6% 36%	2660
	11th to 20th	Day	16% 7% 3 7% 6% 4 4 5% 6% 7% 34%	2660
	21st to end	Day	9% 4 2 5% 3 3 4 3 4 6% 57%	2660
July	1st to 10th	Day	3 2 1 2 2 2 2 2 3 3 79%	4420
	11th to 20th	Day	4 2 1 2 2 2 2 2 2 3 78%	4420
	21st to end	Day	4 2 1 2 2 1 2 2 3 4 78%	4731
August	1st to 10th	Day	2 3 1 3 2 3 3 2 4 6% 72%	4091
	11th to 20th	Day	5% 3 1 5% 3 3 4 4 4 8% 60%	4026
	21st to end	Day	6% 6% 2 4 3 3 3 3 4 6% 59%	4306
September	1st to 10th	Day	6% 3 1 3 2 2 3 2 3 6% 67%	2280
	11th to 20th	Day	11% 7% 2 6% 5% 3 4 4 5% 7% 45%	2260
	21st to end	Day	15% 6% 3 6% 4 4 3 3 4 5% 48%	2009
October	1st to 10th	Day	15% 7% 3 7% 4 4 5% 3 5% 6% 41%	1900
	11th to 20th	Day	17% 9% 5% 9% 5% 6% 4 3 4 6% 30%	1900
	21st to end	Day	24% 11% 3 9% 5% 5% 5% 3 4 6% 27%	2084
November	1st to 10th	Day	30% 12% 5% 10% 6% 4 5% 3 4 4 16%	1587
	11th to 20th	Day	30% 12% 5% 9% 5% 6% 3 4 5% 6% 17%	1520
	21st to end	Day	27% 11% 4 11% 7% 6% 4 3 5% 5% 19%	1520
December	1st to 10th	Day	26% 10% 6% 11% 7% 3 4 3 5% 5% 21%	1520
	11th to 20th	Day	28% 12% 4 12% 7% 6% 5% 5% 6% 4 9%	1928
	21st to end	Day	32% 14% 5% 17% 7% 5% 4 3 3 4 6%	2794
January	1st to 10th	Night	34% 17% 6% 11% 6% 4 4 3 3 3 9%	4406
	11th to 20th	Night	38% 14% 4 8% 4 4 4 2 3 4 15%	4416
	21st to end	Night	36% 13% 5% 10% 4 5% 3 2 4 4 14%	4521
February	1st to 10th	Night	27% 13% 4 10% 7% 5% 4 4 4 6% 17%	2470
	11th to 20th	Night	27% 11% 4 8% 5% 5% 4 3 4 5% 24%	2402
	21st to end	Night	29% 11% 3 8% 5% 4 4 4 4 6% 22%	1970
March	1st to 10th	Night	19% 14% 4 11% 7% 6% 6% 4 6% 5% 19%	3530
	11th to 20th	Night	17% 8% 2 7% 4 5% 4 3 6% 6% 38%	3490
	21st to end	Night	22% 13% 4 12% 6% 6% 5% 4 5% 5% 17%	3777
April	1st to 10th	Night	28% 11% 3 8% 5% 4 4 3 5% 5% 24%	1900
	11th to 20th	Night	21% 9% 2 6% 4 4 4 4 5% 6% 33%	1879
	21st to end	Night	21% 8% 2 6% 5% 4 4 3 6% 8% 33%	1713
May	1st to 10th	Night	23% 7% 3 7% 4 3 3 3 4 5% 38%	2679
	11th to 20th	Night	9% 5% 2 5% 3 3 3 2 4 5% 58%	2516
	21st to end	Night	14% 6% 2 5% 4 4 5% 4 7% 9% 39%	2762
June	1st to 10th	Night	17% 7% 2 6% 4 3 4 4 6% 7% 41%	1520
	11th to 20th	Night	12% 6% 2 6% 5% 4 4 3 5% 8% 43%	1520
	21st to end	Night	6% 5% 2 4 3 3 3 3 4 5% 62%	1520
July	1st to 10th	Night	3 2 1 2 2 1 2 1 2 3 82%	2540
	11th to 20th	Night	4 3 1 2 2 1 1 2 2 3 80%	2540
	21st to end	Night	3 2 1 2 1 1 1 1 2 3 81%	2818
August	1st to 10th	Night	2 2 2 1 2 2 2 4 5% 77%	2848
	11th to 20th	Night	5% 3 2 3 3 3 4 3 4 6% 63%	2812
	21st to end	Night	8% 3 2 4 3 2 2 2 3 5% 66%	3366
September	1st to 10th	Night	6% 3 1 3 2 3 3 2 4 5% 69%	1900
	11th to 20th	Night	8% 4 2 5% 3 5% 5% 4 5% 5% 54%	1917
	21st to end	Night	10% 5% 2 5% 4 4 3 3 5% 7% 53%	2171
October	1st to 10th	Night	14% 7% 2 7% 4 4 4 3 4 6% 47%	2280
	11th to 20th	Night	16% 7% 2 6% 5% 5% 4 4 5% 7% 39%	2280
	21st to end	Night	22% 9% 3 7% 4 4 4 3 4 5% 36%	2513
November	1st to 10th	Night	27% 10% 3 8% 5% 5% 5% 4 5% 6% 24%	2513
	11th to 20th	Night	31% 9% 3 8% 5% 4 5% 3 4 5% 21%	2660
	21st to end	Night	23% 9% 3 10% 6% 5% 4 4 5% 5% 26%	2660
December	1st to 10th	Night	28% 10% 4 8% 6% 3 4 3 5% 6% 24%	2660
	11th to 20th	Night	28% 11% 4 12% 7% 6% 5% 4 5% 4 14%	3276
	21st to end	Night	27% 13% 7% 14% 7% 5% 5% 3 4 3 10%	4862

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% 11% 5% 3 1 1	2539
	11th to 20th	Day	77% 6% 6% 7% 2 2	2541
	21st to end	Day	71% 11% 8% 6% 4	3146
February	1st to 10th	Day	70% 8% 9% 8% 4	1710
	11th to 20th	Day	68% 9% 9% 9% 4 1	1674
	21st to end	Day	70% 7% 7% 9% 5% 2	1484
March	1st to 10th	Day	61% 13% 12% 12% 2	3340
	11th to 20th	Day	47% 9% 11% 23% 10%	3490
	21st to end	Day	65% 12% 12% 7% 4	3876
April	1st to 10th	Day	65% 9% 12% 11% 4	2280
	11th to 20th	Day	58% 9% 11% 13% 7% 3	2252
	21st to end	Day	55% 9% 14% 13% 7% 1	2464
May	1st to 10th	Day	47% 11% 13% 17% 11%	4282
	11th to 20th	Day	29% 7% 18% 32% 13% 1	4380
	21st to end	Day	45% 15% 22% 16% 2	4814
June	1st to 10th	Day	49% 6% 18% 20% 6% 1	2660
	11th to 20th	Day	46% 9% 21% 18% 6%	2660
	21st to end	Day	28% 6% 18% 30% 13% 4	2660
July	1st to 10th	Day	12% 4 9% 18% 25% 32%	4351
	11th to 20th	Day	14% 3 6% 18% 37% 23%	4345
	21st to end	Day	12% 3 10% 28% 38% 9%	4581
August	1st to 10th	Day	15% 4 10% 30% 28% 11%	4076
	11th to 20th	Day	22% 7% 18% 33% 17% 3	4065
	21st to end	Day	24% 7% 13% 24% 25% 6%	4305
September	1st to 10th	Day	19% 4 13% 31% 21% 12%	2280
	11th to 20th	Day	37% 9% 13% 21% 15% 7%	2260
	21st to end	Day	38% 7% 14% 20% 16% 6%	2009
October	1st to 10th	Day	42% 7% 11% 19% 16% 4	1900
	11th to 20th	Day	53% 8% 12% 14% 11% 2	1900
	21st to end	Day	59% 8% 9% 12% 11% 2	2084
November	1st to 10th	Day	70% 8% 10% 9% 4	1587
	11th to 20th	Day	68% 8% 10% 7% 6% 2	1520
	21st to end	Day	66% 7% 8% 7% 11% 1	1520
December	1st to 10th	Day	65% 8% 9% 9% 9% 1	1520
	11th to 20th	Day	71% 12% 8% 8% 1	1928
	21st to end	Day	78% 11% 6% 3 2	2794
January	1st to 10th	Night	77% 8% 7% 3 3 1	4406
	11th to 20th	Night	74% 6% 6% 10% 3 1	4416
	21st to end	Night	71% 8% 7% 8% 5% 1	4521
February	1st to 10th	Night	66% 10% 10% 10% 4 1	2470
	11th to 20th	Night	60% 8% 13% 10% 6% 2	2404
	21st to end	Night	62% 8% 12% 11% 6% 2	1970
March	1st to 10th	Night	59% 12% 14% 12% 4	3530
	11th to 20th	Night	40% 11% 15% 24% 10% 1	3490
	21st to end	Night	64% 12% 13% 10% 1	3777
April	1st to 10th	Night	62% 7% 14% 12% 5%	1900
	11th to 20th	Night	50% 10% 17% 14% 6% 3	1879
	21st to end	Night	50% 8% 17% 18% 5% 2	1713
May	1st to 10th	Night	46% 9% 15% 20% 9% 1	2679
	11th to 20th	Night	27% 6% 18% 35% 12% 2	2516
	21st to end	Night	36% 15% 32% 14% 3	2762
June	1st to 10th	Night	41% 9% 18% 26% 5% 1	1520
	11th to 20th	Night	38% 7% 23% 24% 8%	1520
	21st to end	Night	24% 5% 20% 34% 14% 4	1520
July	1st to 10th	Night	10% 3 9% 20% 25% 33%	2500
	11th to 20th	Night	13% 3 7% 19% 31% 28%	2492
	21st to end	Night	10% 3 11% 30% 38% 9%	2730
August	1st to 10th	Night	10% 3 10% 38% 28% 10%	2839
	11th to 20th	Night	20% 6% 21% 36% 14% 4	2839
	21st to end	Night	22% 5% 12% 30% 25% 6%	3366
September	1st to 10th	Night	18% 5% 12% 31% 23% 11%	1900
	11th to 20th	Night	30% 7% 14% 26% 14% 9%	1917
	21st to end	Night	31% 6% 16% 23% 16% 8%	2171
October	1st to 10th	Night	37% 6% 10% 25% 18% 4	2280
	11th to 20th	Night	41% 8% 14% 19% 14% 4	2280
	21st to end	Night	49% 8% 12% 14% 15% 2	2513
November	1st to 10th	Night	58% 9% 11% 15% 7%	2513
	11th to 20th	Night	64% 8% 10% 9% 7% 2	2660
	21st to end	Night	56% 9% 10% 11% 12% 3	2660
December	1st to 10th	Night	60% 7% 11% 12% 9% 1	2660
	11th to 20th	Night	66% 11% 10% 9% 4	3276
	21st to end	Night	72% 12% 8% 6% 2	4862

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	41% 14% 18% 14% 11% 2	180
	11th to 20th	Day	32% 14% 15% 24% 11% 4	181
	21st to end	Day	31% 12% 18% 20% 15% 5%	407
February	1st to 10th	Day	30% 9% 22% 21% 14% 4	370
	11th to 20th	Day	29% 10% 25% 21% 10% 4	365
	21st to end	Day	24% 18% 23% 21% 11% 3	341
March	1st to 10th	Day	28% 13% 24% 23% 10% 2	460
	11th to 20th	Day	24% 12% 21% 23% 16% 4	460
	21st to end	Day	25% 16% 25% 23% 10% 2	506
April	1st to 10th	Day	27% 14% 21% 20% 14% 4	460
	11th to 20th	Day	24% 15% 25% 21% 10% 5%	452
	21st to end	Day	20% 13% 25% 25% 15% 2	460
May	1st to 10th	Day	15% 12% 25% 27% 16% 5%	463
	11th to 20th	Day	22% 9% 18% 24% 19% 8%	488
	21st to end	Day	13% 8% 22% 26% 22% 10%	529
June	1st to 10th	Day	18% 8% 18% 28% 23% 4	490
	11th to 20th	Day	14% 9% 24% 33% 18% 2	490
	21st to end	Day	5% 4 16% 38% 30% 8%	490
July	1st to 10th	Day	6% 2 16% 37% 30% 9%	486
	11th to 20th	Day	2 2 20% 36% 31% 9%	484
	21st to end	Day	3 2 12% 38% 34% 11%	531
August	1st to 10th	Day	2 1 13% 32% 39% 13%	487
	11th to 20th	Day	3 2 9% 36% 36% 15%	477
	21st to end	Day	4 3 18% 35% 31% 9%	539
September	1st to 10th	Day	6% 3 19% 32% 31% 9%	490
	11th to 20th	Day	11% 4 17% 30% 28% 9%	490
	21st to end	Day	14% 6% 19% 31% 22% 7%	490
October	1st to 10th	Day	16% 7% 21% 25% 22% 9%	490
	11th to 20th	Day	18% 7% 18% 25% 24% 8%	490
	21st to end	Day	25% 12% 22% 22% 14% 6%	533
November	1st to 10th	Day	26% 11% 27% 19% 12% 4	227
	11th to 20th	Day	23% 12% 25% 19% 15% 6%	180
	21st to end	Day	29% 11% 19% 18% 16% 6%	180
December	1st to 10th	Day	27% 17% 14% 23% 13% 6%	180
	11th to 20th	Day	37% 7% 21% 22% 11% 3	180
	21st to end	Day	33% 14% 18% 20% 14% 1	198
January	1st to 10th	Night	35% 10% 20% 21% 12% 2	760
	11th to 20th	Night	33% 10% 17% 20% 17% 3	760
	21st to end	Night	30% 5% 16% 31% 16% 3	836
February	1st to 10th	Night	28% 8% 18% 27% 17% 2	760
	11th to 20th	Night	27% 7% 20% 28% 16% 1	744
	21st to end	Night	27% 10% 22% 26% 14%	628
March	1st to 10th	Night	27% 8% 22% 30% 14%	760
	11th to 20th	Night	23% 8% 18% 33% 16% 1	760
	21st to end	Night	27% 9% 22% 28% 13% 1	836
April	1st to 10th	Night	29% 6% 21% 26% 17% 1	760
	11th to 20th	Night	21% 7% 23% 31% 17% 1	751
	21st to end	Night	21% 6% 21% 34% 17% 1	573
May	1st to 10th	Night	13% 6% 25% 37% 18% 1	467
	11th to 20th	Night	16% 2 17% 38% 26% 1	374
	21st to end	Night	15% 5% 19% 37% 22% 1	411
June	1st to 10th	Night	17% 5% 16% 41% 21%	380
	11th to 20th	Night	12% 4 21% 47% 15% 1	380
	21st to end	Night	6% 2 18% 53% 21%	380
July	1st to 10th	Night	5% 1 11% 55% 28% 1	370
	11th to 20th	Night	4 2 22% 49% 23% 1	368
	21st to end	Night	2 2 12% 52% 31% 2	449
August	1st to 10th	Night	3 1 7% 43% 41% 5%	567
	11th to 20th	Night	4 1 5% 41% 46% 2	564
	21st to end	Night	6% 2 15% 43% 32% 2	756
September	1st to 10th	Night	6% 1 14% 44% 33% 1	760
	11th to 20th	Night	9% 3 12% 38% 32% 6%	760
	21st to end	Night	11% 3 15% 40% 29% 3	760
October	1st to 10th	Night	14% 3 21% 33% 27% 3	760
	11th to 20th	Night	17% 5% 14% 35% 26% 4	760
	21st to end	Night	24% 6% 20% 29% 17% 4	836
November	1st to 10th	Night	26% 7% 19% 30% 17% 1	744
	11th to 20th	Night	31% 8% 21% 24% 15% 1	760
	21st to end	Night	23% 8% 18% 30% 18% 3	760
December	1st to 10th	Night	26% 7% 18% 29% 17% 3	760
	11th to 20th	Night	31% 9% 21% 22% 17% 1	760
	21st to end	Night	35% 8% 21% 24% 11% 1	836

Page generated at 2024-10-29 22:22:53. Version ac07

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