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 2024-03-01.

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	11% 5% 2 5% 6% 3 5% 5% 6% 8% 42%	78929
	Night	11% 6% 2 5% 5% 3 5% 5% 6% 8% 45%	80487
Transparency	Day	38% 7% 12% 17% 18% 7%	78652
	Night	36% 7% 12% 17% 19% 9%	80283
Seeing	Day	12% 6% 19% 24% 23% 15%	14011
	Night	12% 5% 21% 33% 24% 4	24136

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	14% 5% 2 6% 5% 3 5% 5% 5% 6% 45%	2836
	11th to 20th	Day	14% 6% 2 3 3 2 3 3 6% 8% 52%	2840
	21st to end	Day	17% 7% 3 6% 5% 3 4 4 4 6% 42%	3385
February	1st to 10th	Day	15% 7% 3 5% 6% 3 4 4 5% 6% 41%	1900
	11th to 20th	Day	17% 6% 2 5% 5% 2 4 4 4 6% 46%	1848
	21st to end	Day	15% 6% 3 5% 4 3 4 5% 6% 6% 44%	1570
March	1st to 10th	Day	10% 6% 2 5% 4 3 3 3 5% 8% 52%	1876
	11th to 20th	Day	12% 6% 2 5% 5% 4 6% 4 5% 7% 43%	1980
	21st to end	Day	12% 6% 2 4 4 3 5% 5% 5% 7% 47%	2178
April	1st to 10th	Day	12% 5% 2 5% 5% 3 5% 5% 6% 6% 46%	1980
	11th to 20th	Day	12% 5% 2 4 6% 3 5% 5% 5% 8% 47%	2122
	21st to end	Day	7% 3 2 4 5% 3 4 4 5% 7% 56%	2258
May	1st to 10th	Day	8% 3 2 4 5% 3 4 5% 5% 8% 54%	2340
	11th to 20th	Day	6% 4 3 6% 6% 4 6% 6% 8% 9% 39%	2301
	21st to end	Day	7% 4 2 5% 7% 4 6% 6% 7% 9% 44%	2531
June	1st to 10th	Day	10% 6% 3 7% 7% 4 7% 7% 7% 9% 33%	2340
	11th to 20th	Day	5% 4 2 6% 7% 4 8% 8% 7% 11% 38%	2340
	21st to end	Day	6% 5% 2 7% 8% 5% 8% 8% 10% 12% 30%	2340
July	1st to 10th	Day	8% 5% 3 8% 9% 5% 7% 8% 9% 11% 26%	2340
	11th to 20th	Day	8% 6% 3 7% 8% 6% 7% 7% 8% 12% 29%	2340
	21st to end	Day	7% 5% 3 7% 7% 5% 8% 8% 9% 11% 31%	2547
August	1st to 10th	Day	9% 6% 3 6% 7% 5% 8% 8% 9% 11% 28%	2276
	11th to 20th	Day	11% 5% 2 7% 9% 5% 7% 8% 8% 11% 26%	2125
	21st to end	Day	11% 8% 3 8% 10% 5% 6% 8% 6% 8% 28%	2346
September	1st to 10th	Day	8% 5% 3 7% 7% 4 7% 7% 7% 9% 35%	1980
	11th to 20th	Day	10% 6% 2 6% 8% 5% 6% 4 7% 9% 36%	1980
	21st to end	Day	11% 4 2 6% 5% 3 5% 4 5% 7% 45%	1980
October	1st to 10th	Day	12% 5% 2 4 4 3 4 4 5% 6% 51%	1980
	11th to 20th	Day	10% 4 2 4 3 3 4 4 3 7% 57%	1906
	21st to end	Day	9% 4 2 4 5% 3 4 4 4 6% 55%	1980
November	1st to 10th	Day	10% 5% 2 4 4 2 4 4 5% 5% 55%	1777
	11th to 20th	Day	11% 5% 2 4 5% 2 3 4 4 5% 56%	1710
	21st to end	Day	13% 5% 2 5% 5% 2 4 3 5% 6% 48%	1710
December	1st to 10th	Day	15% 5% 3 4 5% 3 4 5% 5% 6% 44%	1710
	11th to 20th	Day	18% 7% 2 5% 4 3 4 3 5% 6% 43%	2153
	21st to end	Day	18% 9% 3 6% 5% 2 3 3 4 5% 42%	3124
January	1st to 10th	Night	15% 5% 2 5% 5% 3 5% 4 5% 7% 44%	4109
	11th to 20th	Night	9% 5% 3 5% 5% 3 5% 5% 6% 7% 48%	4120
	21st to end	Night	17% 10% 2 5% 4 2 4 3 4 6% 40%	4267
February	1st to 10th	Night	14% 6% 3 5% 4 3 4 4 6% 6% 45%	2280
	11th to 20th	Night	17% 6% 2 5% 4 2 3 3 4 6% 47%	2218
	21st to end	Night	14% 6% 3 4 4 2 4 5% 5% 6% 46%	1884
March	1st to 10th	Night	12% 5% 3 4 4 3 4 3 4 6% 52%	2091
	11th to 20th	Night	12% 5% 2 5% 4 2 5% 5% 5% 7% 47%	1980
	21st to end	Night	9% 5% 1 5% 5% 3 4 4 5% 7% 51%	2178
April	1st to 10th	Night	10% 4 2 4 5% 3 4 4 5% 8% 50%	1980
	11th to 20th	Night	10% 5% 2 4 5% 3 4 4 6% 8% 49%	1801
	21st to end	Night	7% 3 1 3 4 2 4 4 6% 8% 58%	1702
May	1st to 10th	Night	6% 4 2 5% 4 3 4 4 6% 8% 55%	1620
	11th to 20th	Night	6% 5% 2 5% 5% 4 6% 6% 6% 10% 45%	1592
	21st to end	Night	6% 4 2 6% 5% 3 5% 5% 6% 9% 47%	1744
June	1st to 10th	Night	8% 6% 4 7% 7% 4 6% 7% 7% 12% 33%	1620
	11th to 20th	Night	5% 4 2 6% 5% 3 6% 5% 10% 11% 42%	1620
	21st to end	Night	6% 4 3 7% 6% 5% 6% 8% 8% 12% 36%	1620
July	1st to 10th	Night	8% 5% 3 6% 7% 5% 7% 9% 9% 12% 29%	1620
	11th to 20th	Night	5% 5% 3 6% 6% 4 7% 8% 9% 13% 33%	1620
	21st to end	Night	4 4 2 5% 7% 4 6% 7% 9% 13% 38%	1771
August	1st to 10th	Night	6% 5% 2 6% 7% 4 7% 7% 10% 14% 31%	1656
	11th to 20th	Night	8% 4 3 7% 7% 5% 6% 8% 8% 13% 31%	1776
	21st to end	Night	8% 7% 4 7% 7% 4 7% 8% 8% 10% 31%	1989
September	1st to 10th	Night	8% 6% 3 6% 7% 5% 6% 6% 8% 11% 33%	1980
	11th to 20th	Night	10% 6% 3 6% 7% 4 5% 5% 7% 9% 38%	1980
	21st to end	Night	8% 6% 2 5% 6% 4 6% 6% 6% 8% 43%	1980
October	1st to 10th	Night	9% 6% 1 4 4 2 4 4 5% 8% 53%	1980
	11th to 20th	Night	10% 6% 2 3 4 3 3 3 4 6% 58%	2052
	21st to end	Night	9% 4 3 4 4 3 5% 4 4 5% 55%	2376
November	1st to 10th	Night	10% 4 2 4 4 2 4 4 4 6% 56%	2297
	11th to 20th	Night	12% 5% 2 4 4 2 3 3 4 7% 54%	2470
	21st to end	Night	14% 5% 2 4 4 3 4 4 5% 7% 47%	2470
December	1st to 10th	Night	13% 6% 2 5% 4 3 5% 4 6% 7% 46%	2470
	11th to 20th	Night	14% 7% 2 5% 4 2 3 4 4 5% 49%	3042
	21st to end	Night	17% 9% 4 6% 5% 3 4 4 5% 6% 37%	4532

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	39% 5% 7% 17% 22% 11%	2837
	11th to 20th	Day	31% 3 7% 19% 27% 14%	2840
	21st to end	Day	43% 5% 6% 13% 21% 13%	3385
February	1st to 10th	Day	44% 4 8% 15% 20% 10%	1900
	11th to 20th	Day	40% 4 5% 14% 27% 10%	1858
	21st to end	Day	39% 6% 9% 18% 18% 11%	1570
March	1st to 10th	Day	32% 4 7% 20% 24% 12%	1876
	11th to 20th	Day	39% 6% 12% 15% 19% 9%	1980
	21st to end	Day	37% 6% 10% 19% 21% 7%	2178
April	1st to 10th	Day	39% 5% 9% 19% 17% 11%	1980
	11th to 20th	Day	35% 5% 8% 19% 24% 10%	2122
	21st to end	Day	28% 5% 9% 24% 25% 8%	2258
May	1st to 10th	Day	27% 5% 11% 23% 25% 9%	2340
	11th to 20th	Day	36% 9% 15% 21% 16% 4	2305
	21st to end	Day	34% 8% 12% 24% 18% 4	2531
June	1st to 10th	Day	44% 9% 16% 21% 9% 1	2340
	11th to 20th	Day	34% 12% 17% 22% 13% 1	2340
	21st to end	Day	41% 12% 22% 15% 9% 2	2340
July	1st to 10th	Day	46% 13% 22% 14% 5% 1	2275
	11th to 20th	Day	43% 15% 22% 14% 5% 1	2271
	21st to end	Day	39% 14% 22% 19% 5% 1	2405
August	1st to 10th	Day	43% 13% 21% 19% 3	2263
	11th to 20th	Day	46% 14% 20% 14% 6%	2125
	21st to end	Day	51% 11% 16% 13% 7% 2	2346
September	1st to 10th	Day	42% 11% 18% 13% 13% 3	1980
	11th to 20th	Day	43% 8% 13% 15% 15% 5%	1980
	21st to end	Day	37% 6% 11% 19% 20% 7%	1980
October	1st to 10th	Day	34% 5% 10% 17% 22% 11%	1980
	11th to 20th	Day	28% 5% 8% 23% 27% 9%	1906
	21st to end	Day	31% 5% 5% 14% 28% 17%	1980
November	1st to 10th	Day	31% 4 9% 16% 24% 16%	1777
	11th to 20th	Day	31% 4 6% 17% 28% 14%	1710
	21st to end	Day	36% 4 8% 19% 23% 10%	1710
December	1st to 10th	Day	39% 6% 13% 14% 19% 9%	1710
	11th to 20th	Day	43% 3 6% 16% 24% 8%	2150
	21st to end	Day	47% 3 5% 16% 24% 5%	3124
January	1st to 10th	Night	39% 4 9% 12% 21% 15%	4109
	11th to 20th	Night	36% 4 6% 16% 28% 11%	4120
	21st to end	Night	45% 5% 5% 13% 23% 8%	4267
February	1st to 10th	Night	41% 4 8% 16% 20% 12%	2280
	11th to 20th	Night	40% 4 7% 13% 21% 15%	2219
	21st to end	Night	37% 6% 7% 18% 16% 16%	1884
March	1st to 10th	Night	33% 6% 7% 17% 23% 15%	2091
	11th to 20th	Night	36% 5% 10% 19% 18% 11%	1980
	21st to end	Night	32% 5% 12% 19% 23% 10%	2178
April	1st to 10th	Night	33% 6% 10% 18% 19% 14%	1980
	11th to 20th	Night	33% 4 10% 17% 26% 10%	1801
	21st to end	Night	23% 5% 12% 26% 25% 9%	1702
May	1st to 10th	Night	26% 7% 10% 22% 24% 11%	1620
	11th to 20th	Night	33% 10% 16% 17% 18% 7%	1593
	21st to end	Night	31% 9% 16% 20% 19% 5%	1745
June	1st to 10th	Night	39% 12% 16% 21% 11% 1	1620
	11th to 20th	Night	31% 11% 21% 24% 11% 1	1620
	21st to end	Night	37% 12% 23% 16% 10% 2	1620
July	1st to 10th	Night	42% 17% 21% 13% 6% 1	1575
	11th to 20th	Night	35% 15% 29% 13% 7%	1566
	21st to end	Night	32% 14% 25% 23% 5% 1	1672
August	1st to 10th	Night	37% 13% 29% 16% 4	1645
	11th to 20th	Night	40% 16% 23% 17% 4 1	1776
	21st to end	Night	44% 14% 18% 14% 8% 2	1989
September	1st to 10th	Night	42% 12% 18% 13% 12% 3	1980
	11th to 20th	Night	41% 9% 15% 14% 17% 4	1980
	21st to end	Night	36% 8% 13% 15% 21% 7%	1980
October	1st to 10th	Night	30% 5% 12% 19% 20% 13%	1980
	11th to 20th	Night	28% 4 8% 20% 29% 11%	2052
	21st to end	Night	32% 3 6% 13% 27% 18%	2376
November	1st to 10th	Night	29% 4 9% 16% 25% 17%	2297
	11th to 20th	Night	31% 4 7% 15% 27% 16%	2470
	21st to end	Night	36% 5% 8% 19% 20% 13%	2470
December	1st to 10th	Night	37% 6% 12% 16% 22% 7%	2470
	11th to 20th	Night	38% 4 6% 15% 26% 10%	3044
	21st to end	Night	48% 4 7% 15% 22% 4	4532

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	12% 17% 44% 20% 7% 1	270
	11th to 20th	Day	11% 18% 32% 25% 10% 3	270
	21st to end	Day	22% 21% 41% 12% 4	297
February	1st to 10th	Day	17% 16% 36% 22% 8% 1	270
	11th to 20th	Day	24% 12% 38% 20% 5%	270
	21st to end	Day	15% 17% 39% 25% 4	225
March	1st to 10th	Day	12% 12% 33% 28% 13% 1	316
	11th to 20th	Day	14% 9% 38% 25% 12% 1	420
	21st to end	Day	13% 12% 33% 27% 13% 1	462
April	1st to 10th	Day	17% 11% 24% 28% 17% 2	420
	11th to 20th	Day	15% 9% 27% 26% 18% 4	412
	21st to end	Day	8% 7% 21% 35% 22% 6%	420
May	1st to 10th	Day	7% 8% 24% 28% 24% 9%	423
	11th to 20th	Day	9% 2 14% 30% 30% 14%	447
	21st to end	Day	9% 2 11% 24% 31% 23%	485
June	1st to 10th	Day	12% 2 10% 26% 32% 19%	450
	11th to 20th	Day	8% 2 9% 20% 29% 31%	450
	21st to end	Day	9% 1 6% 25% 33% 26%	450
July	1st to 10th	Day	7% 1 4 14% 35% 39%	445
	11th to 20th	Day	9% 2 2 11% 34% 42%	444
	21st to end	Day	7% 1 4 16% 36% 36%	488
August	1st to 10th	Day	10% 1 5% 18% 33% 32%	446
	11th to 20th	Day	8% 2 3 14% 34% 39%	439
	21st to end	Day	10% 3 8% 17% 36% 26%	495
September	1st to 10th	Day	10% 3 8% 21% 32% 27%	450
	11th to 20th	Day	14% 1 10% 27% 33% 16%	450
	21st to end	Day	13% 1 11% 23% 32% 20%	450
October	1st to 10th	Day	11% 3 24% 30% 23% 9%	450
	11th to 20th	Day	10% 5% 16% 32% 28% 10%	450
	21st to end	Day	11% 6% 24% 31% 23% 5%	495
November	1st to 10th	Day	14% 5% 23% 31% 22% 5%	375
	11th to 20th	Day	12% 9% 38% 29% 10% 2	270
	21st to end	Day	12% 13% 27% 32% 14% 2	270
December	1st to 10th	Day	21% 10% 28% 27% 12% 3	270
	11th to 20th	Day	26% 11% 31% 22% 9% 1	270
	21st to end	Day	20% 12% 27% 28% 12% 1	297
January	1st to 10th	Night	16% 10% 36% 32% 6% 1	760
	11th to 20th	Night	13% 10% 31% 34% 11% 1	760
	21st to end	Night	20% 10% 36% 28% 5%	836
February	1st to 10th	Night	17% 10% 30% 36% 8%	760
	11th to 20th	Night	19% 9% 32% 34% 6%	743
	21st to end	Night	16% 9% 36% 35% 4	628
March	1st to 10th	Night	14% 9% 29% 39% 9%	723
	11th to 20th	Night	13% 8% 34% 31% 13% 1	720
	21st to end	Night	11% 9% 31% 36% 12% 1	792
April	1st to 10th	Night	14% 7% 27% 37% 16%	720
	11th to 20th	Night	11% 7% 27% 38% 16% 1	559
	21st to end	Night	7% 2 27% 39% 24% 1	540
May	1st to 10th	Night	8% 4 23% 41% 21% 1	540
	11th to 20th	Night	9% 2 20% 37% 28% 4	531
	21st to end	Night	8% 1 11% 39% 35% 6%	584
June	1st to 10th	Night	9% 2 9% 38% 37% 6%	540
	11th to 20th	Night	6% 1 7% 31% 42% 13%	540
	21st to end	Night	7% 1 6% 31% 45% 11%	540
July	1st to 10th	Night	9% 2 4 24% 46% 16%	525
	11th to 20th	Night	8% 1 3 19% 48% 20%	522
	21st to end	Night	5% 4 26% 49% 16%	591
August	1st to 10th	Night	9% 1 6% 23% 45% 16%	537
	11th to 20th	Night	10% 2 3 18% 54% 13%	534
	21st to end	Night	11% 2 6% 26% 39% 16%	603
September	1st to 10th	Night	11% 3 7% 27% 42% 11%	720
	11th to 20th	Night	13% 4 9% 33% 36% 5%	720
	21st to end	Night	10% 3 13% 33% 37% 5%	720
October	1st to 10th	Night	12% 2 17% 39% 27% 3	720
	11th to 20th	Night	13% 4 18% 34% 28% 3	720
	21st to end	Night	11% 4 22% 36% 25% 2	792
November	1st to 10th	Night	12% 5% 20% 38% 22% 2	740
	11th to 20th	Night	14% 7% 29% 34% 15% 1	760
	21st to end	Night	14% 6% 28% 33% 17% 1	760
December	1st to 10th	Night	15% 6% 29% 35% 13% 2	760
	11th to 20th	Night	17% 5% 31% 31% 14% 2	760
	21st to end	Night	21% 8% 26% 33% 11%	836

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