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 2026-09-29.

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	10% 5% 2 6% 5% 5% 5% 4 7% 9% 41%	148691
	Night	11% 6% 2 6% 4 4 5% 4 6% 8% 43%	142710
Transparency	Day	38% 6% 15% 19% 16% 7%	152490
	Night	37% 6% 13% 17% 18% 9%	146970
Seeing	Day	12% 6% 19% 24% 24% 14%	17533
	Night	13% 5% 21% 33% 24% 4	27479

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	12% 6% 2 7% 4 4 4 3 4 6% 48%	5258
	11th to 20th	Day	15% 5% 2 3 2 3 3 3 6% 8% 51%	5280
	21st to end	Day	13% 7% 3 7% 4 4 5% 4 5% 8% 41%	6289
February	1st to 10th	Day	14% 7% 2 6% 5% 5% 4 4 6% 6% 42%	2100
	11th to 20th	Day	17% 7% 2 5% 4 4 3 3 5% 6% 45%	2048
	21st to end	Day	15% 6% 2 5% 3 4 4 4 6% 6% 44%	1730
March	1st to 10th	Day	18% 7% 2 6% 4 4 4 3 6% 7% 39%	4786
	11th to 20th	Day	8% 5% 2 5% 3 4 4 3 5% 7% 54%	5090
	21st to end	Day	14% 7% 2 5% 4 4 4 3 5% 6% 47%	5586
April	1st to 10th	Day	11% 6% 2 5% 5% 4 5% 4 6% 6% 46%	2310
	11th to 20th	Day	10% 4 2 4 5% 3 5% 4 5% 7% 50%	2481
	21st to end	Day	7% 4 1 6% 5% 4 4 4 6% 7% 53%	2635
May	1st to 10th	Day	15% 7% 3 7% 5% 4 4 4 5% 8% 39%	7616
	11th to 20th	Day	12% 5% 2 6% 4 4 5% 4 7% 11% 39%	7626
	21st to end	Day	6% 5% 2 7% 6% 6% 6% 6% 8% 10% 37%	8391
June	1st to 10th	Day	9% 6% 3 8% 7% 5% 6% 6% 8% 9% 33%	2730
	11th to 20th	Day	5% 4 2 7% 6% 6% 7% 7% 8% 11% 37%	2730
	21st to end	Day	6% 5% 2 8% 6% 7% 7% 6% 9% 11% 33%	2730
July	1st to 10th	Day	7% 5% 2 8% 7% 7% 8% 7% 10% 12% 27%	7680
	11th to 20th	Day	5% 4 2 6% 6% 7% 7% 6% 9% 14% 36%	7680
	21st to end	Day	5% 5% 2 8% 6% 7% 8% 7% 10% 15% 28%	8340
August	1st to 10th	Day	11% 5% 2 7% 6% 6% 7% 6% 9% 12% 28%	5876
	11th to 20th	Day	4 3 1 5% 4 5% 6% 6% 8% 12% 46%	5486
	21st to end	Day	8% 7% 2 8% 6% 6% 6% 6% 8% 12% 31%	5992
September	1st to 10th	Day	10% 5% 2 8% 5% 5% 7% 6% 7% 9% 36%	2310
	11th to 20th	Day	10% 6% 2 7% 6% 6% 5% 3 7% 8% 38%	2310
	21st to end	Day	11% 4 2 7% 4 4 5% 4 5% 7% 46%	2288
October	1st to 10th	Day	13% 5% 2 6% 3 4 4 3 5% 5% 49%	2200
	11th to 20th	Day	9% 4 1 4 2 3 4 3 3 7% 59%	2117
	21st to end	Day	9% 4 1 5% 4 4 3 3 4 5% 57%	2200
November	1st to 10th	Day	10% 6% 2 4 4 3 4 3 5% 6% 54%	1968
	11th to 20th	Day	10% 5% 2 4 4 2 3 3 3 5% 58%	1890
	21st to end	Day	12% 6% 2 6% 5% 3 4 3 5% 6% 49%	1890
December	1st to 10th	Day	14% 6% 3 5% 4 3 3 3 4 6% 50%	3020
	11th to 20th	Day	15% 7% 2 5% 3 3 3 3 5% 6% 47%	3463
	21st to end	Day	18% 9% 3 6% 3 3 3 3 4 5% 42%	4565
January	1st to 10th	Night	10% 6% 2 5% 4 4 5% 4 6% 7% 49%	7635
	11th to 20th	Night	13% 6% 3 7% 4 4 4 3 4 6% 46%	7680
	21st to end	Night	16% 9% 3 6% 4 3 4 3 5% 7% 40%	7888
February	1st to 10th	Night	13% 7% 2 5% 4 4 4 3 6% 5% 46%	2520
	11th to 20th	Night	17% 7% 2 5% 4 4 3 3 5% 5% 46%	2458
	21st to end	Night	14% 7% 2 5% 4 4 5% 3 5% 6% 46%	2076
March	1st to 10th	Night	19% 9% 3 6% 4 4 3 3 4 6% 40%	5273
	11th to 20th	Night	9% 5% 2 5% 3 3 4 4 6% 8% 51%	5090
	21st to end	Night	13% 5% 2 5% 4 4 4 3 6% 6% 49%	5588
April	1st to 10th	Night	11% 6% 2 5% 5% 4 4 4 6% 7% 48%	2310
	11th to 20th	Night	9% 5% 2 5% 4 4 4 3 5% 8% 52%	2104
	21st to end	Night	7% 4 1 4 4 4 4 4 6% 7% 55%	1984
May	1st to 10th	Night	12% 7% 3 7% 4 4 4 3 6% 9% 39%	5237
	11th to 20th	Night	12% 6% 2 6% 3 4 5% 4 6% 9% 43%	5234
	21st to end	Night	8% 5% 3 7% 5% 6% 5% 5% 8% 11% 37%	5761
June	1st to 10th	Night	8% 7% 3 8% 6% 6% 6% 6% 7% 11% 33%	1890
	11th to 20th	Night	5% 5% 2 7% 5% 5% 6% 4 9% 11% 40%	1890
	21st to end	Night	5% 5% 2 8% 6% 6% 7% 6% 8% 11% 38%	1890
July	1st to 10th	Night	10% 6% 3 9% 6% 7% 7% 6% 8% 11% 28%	5278
	11th to 20th	Night	5% 4 2 7% 5% 7% 7% 7% 11% 15% 31%	5277
	21st to end	Night	6% 5% 3 8% 6% 6% 7% 7% 10% 13% 29%	5736
August	1st to 10th	Night	11% 6% 2 7% 6% 6% 6% 6% 9% 11% 29%	4267
	11th to 20th	Night	5% 3 2 5% 5% 5% 6% 5% 8% 15% 41%	4560
	21st to end	Night	8% 7% 3 7% 6% 5% 6% 6% 8% 12% 34%	5084
September	1st to 10th	Night	9% 6% 2 7% 6% 6% 6% 5% 8% 10% 34%	2310
	11th to 20th	Night	11% 7% 3 7% 5% 5% 4 4 7% 9% 39%	2310
	21st to end	Night	9% 5% 2 6% 5% 5% 6% 4 6% 9% 44%	2289
October	1st to 10th	Night	10% 6% 1 5% 4 3 4 3 6% 8% 51%	2200
	11th to 20th	Night	9% 6% 2 4 3 3 3 2 4 6% 60%	2280
	21st to end	Night	9% 5% 3 5% 3 4 4 3 4 5% 57%	2640
November	1st to 10th	Night	10% 4 2 5% 3 4 4 3 4 6% 56%	2546
	11th to 20th	Night	12% 5% 2 4 3 3 2 2 4 7% 55%	2730
	21st to end	Night	13% 5% 2 5% 4 3 4 3 6% 7% 48%	2730
December	1st to 10th	Night	12% 6% 2 5% 3 3 3 2 4 6% 54%	4380
	11th to 20th	Night	15% 6% 2 5% 3 3 3 3 4 5% 52%	4952
	21st to end	Night	16% 8% 3 6% 4 3 3 3 4 5% 44%	6633

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	37% 3 8% 18% 28% 6%	5259
	11th to 20th	Day	32% 2 6% 16% 27% 17%	5280
	21st to end	Day	43% 3 7% 18% 17% 12%	6289
February	1st to 10th	Day	42% 4 7% 15% 21% 10%	2100
	11th to 20th	Day	41% 3 5% 15% 26% 9%	2058
	21st to end	Day	39% 5% 8% 17% 18% 12%	1730
March	1st to 10th	Day	44% 4 8% 17% 17% 10%	4786
	11th to 20th	Day	29% 4 9% 14% 21% 23%	5090
	21st to end	Day	39% 4 8% 21% 17% 11%	5586
April	1st to 10th	Day	38% 5% 9% 20% 16% 12%	2310
	11th to 20th	Day	33% 5% 7% 18% 26% 11%	2481
	21st to end	Day	30% 5% 11% 24% 23% 8%	2635
May	1st to 10th	Day	43% 5% 13% 19% 17% 3	7651
	11th to 20th	Day	38% 5% 17% 25% 13% 2	7630
	21st to end	Day	38% 8% 19% 19% 15% 1	8405
June	1st to 10th	Day	43% 9% 16% 20% 11% 2	2730
	11th to 20th	Day	35% 11% 19% 21% 13% 1	2730
	21st to end	Day	40% 11% 21% 17% 9% 2	2730
July	1st to 10th	Day	44% 8% 29% 16% 3	7615
	11th to 20th	Day	34% 11% 35% 18% 2	7611
	21st to end	Day	39% 10% 30% 18% 3	8156
August	1st to 10th	Day	45% 8% 22% 19% 5%	5863
	11th to 20th	Day	27% 7% 27% 27% 11% 1	5522
	21st to end	Day	43% 6% 21% 22% 6% 1	5992
September	1st to 10th	Day	42% 9% 19% 15% 13% 3	2310
	11th to 20th	Day	42% 7% 12% 18% 17% 4	2310
	21st to end	Day	36% 6% 11% 22% 19% 7%	2288
October	1st to 10th	Day	39% 3 6% 11% 20% 20%	3590
	11th to 20th	Day	17% 3 5% 18% 25% 33%	3422
	21st to end	Day	20% 3 4 20% 38% 16%	3538
November	1st to 10th	Day	31% 4 9% 16% 24% 15%	1968
	11th to 20th	Day	30% 4 7% 17% 29% 14%	1890
	21st to end	Day	35% 4 9% 19% 23% 10%	1890
December	1st to 10th	Day	36% 4 8% 14% 29% 9%	3020
	11th to 20th	Day	38% 3 6% 23% 22% 7%	3460
	21st to end	Day	45% 3 5% 18% 25% 4	4565
January	1st to 10th	Night	34% 3 12% 15% 27% 10%	7636
	11th to 20th	Night	40% 3 4 14% 27% 12%	7680
	21st to end	Night	44% 3 6% 18% 20% 8%	7888
February	1st to 10th	Night	39% 4 7% 16% 22% 12%	2520
	11th to 20th	Night	41% 4 8% 14% 21% 14%	2459
	21st to end	Night	38% 5% 7% 17% 17% 16%	2076
March	1st to 10th	Night	45% 5% 7% 14% 17% 11%	5273
	11th to 20th	Night	31% 4 9% 16% 22% 19%	5090
	21st to end	Night	36% 4 9% 17% 22% 13%	5588
April	1st to 10th	Night	35% 6% 10% 17% 19% 14%	2310
	11th to 20th	Night	31% 4 9% 17% 27% 12%	2104
	21st to end	Night	26% 5% 12% 26% 23% 8%	1984
May	1st to 10th	Night	42% 6% 16% 17% 13% 7%	5264
	11th to 20th	Night	37% 6% 18% 24% 13% 3	5235
	21st to end	Night	39% 8% 18% 20% 13% 2	5771
June	1st to 10th	Night	40% 12% 15% 19% 12% 2	1890
	11th to 20th	Night	33% 11% 21% 22% 11% 2	1890
	21st to end	Night	37% 12% 21% 18% 11% 2	1890
July	1st to 10th	Night	47% 10% 26% 13% 4	5235
	11th to 20th	Night	38% 12% 33% 14% 2	5226
	21st to end	Night	42% 11% 27% 18% 2	5606
August	1st to 10th	Night	44% 9% 26% 18% 3	4256
	11th to 20th	Night	30% 8% 31% 23% 7% 1	4590
	21st to end	Night	41% 8% 24% 21% 5% 1	5084
September	1st to 10th	Night	42% 11% 19% 15% 11% 3	2310
	11th to 20th	Night	40% 9% 14% 15% 18% 4	2310
	21st to end	Night	35% 8% 14% 18% 20% 6%	2289
October	1st to 10th	Night	36% 4 10% 12% 20% 18%	3590
	11th to 20th	Night	16% 2 4 13% 29% 34%	3701
	21st to end	Night	21% 2 4 16% 39% 19%	4252
November	1st to 10th	Night	29% 4 9% 16% 25% 17%	2546
	11th to 20th	Night	31% 4 6% 16% 28% 16%	2730
	21st to end	Night	35% 5% 9% 18% 20% 13%	2730
December	1st to 10th	Night	33% 3 7% 19% 27% 10%	4380
	11th to 20th	Night	36% 3 7% 20% 23% 10%	4954
	21st to end	Night	43% 3 6% 18% 26% 3	6633

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	13% 15% 44% 21% 6% 1	330
	11th to 20th	Day	14% 19% 32% 23% 9% 3	330
	21st to end	Day	21% 19% 41% 15% 5%	363
February	1st to 10th	Day	15% 15% 36% 24% 9% 1	330
	11th to 20th	Day	25% 15% 36% 19% 4	330
	21st to end	Day	15% 19% 37% 24% 4	273
March	1st to 10th	Day	15% 12% 30% 28% 13% 1	419
	11th to 20th	Day	14% 9% 35% 27% 13% 1	540
	21st to end	Day	14% 11% 32% 28% 13% 2	594
April	1st to 10th	Day	16% 12% 26% 27% 16% 3	540
	11th to 20th	Day	12% 9% 26% 27% 21% 5%	532
	21st to end	Day	8% 6% 21% 35% 24% 6%	540
May	1st to 10th	Day	9% 7% 25% 29% 23% 7%	543
	11th to 20th	Day	10% 2 18% 30% 28% 11%	567
	21st to end	Day	9% 2 13% 28% 29% 19%	617
June	1st to 10th	Day	11% 2 11% 27% 31% 18%	570
	11th to 20th	Day	9% 2 11% 19% 31% 28%	570
	21st to end	Day	8% 1 6% 23% 35% 27%	570
July	1st to 10th	Day	7% 2 4 13% 36% 39%	565
	11th to 20th	Day	7% 2 3 11% 33% 44%	564
	21st to end	Day	6% 1 5% 17% 36% 35%	620
August	1st to 10th	Day	11% 2 5% 19% 34% 29%	566
	11th to 20th	Day	7% 2 2 13% 37% 39%	559
	21st to end	Day	10% 3 8% 18% 36% 24%	627
September	1st to 10th	Day	12% 3 8% 21% 31% 25%	570
	11th to 20th	Day	14% 1 8% 27% 33% 16%	570
	21st to end	Day	13% 2 12% 21% 32% 20%	562
October	1st to 10th	Day	14% 3 22% 31% 22% 8%	530
	11th to 20th	Day	9% 5% 18% 30% 28% 9%	530
	21st to end	Day	11% 5% 24% 32% 24% 4	583
November	1st to 10th	Day	14% 5% 21% 32% 23% 5%	446
	11th to 20th	Day	11% 8% 35% 30% 12% 5%	330
	21st to end	Day	11% 15% 29% 30% 13% 2	330
December	1st to 10th	Day	23% 9% 30% 25% 11% 2	330
	11th to 20th	Day	23% 11% 32% 22% 9% 3	330
	21st to end	Day	18% 12% 27% 28% 13% 1	363
January	1st to 10th	Night	15% 10% 36% 33% 6%	840
	11th to 20th	Night	14% 10% 32% 34% 10%	840
	21st to end	Night	20% 9% 36% 30% 5%	924
February	1st to 10th	Night	16% 10% 30% 36% 8%	840
	11th to 20th	Night	19% 10% 33% 32% 6%	823
	21st to end	Night	16% 10% 36% 34% 4	692
March	1st to 10th	Night	15% 8% 29% 38% 10%	840
	11th to 20th	Night	13% 8% 34% 33% 11% 1	840
	21st to end	Night	12% 9% 30% 37% 12% 1	924
April	1st to 10th	Night	14% 7% 28% 36% 15%	840
	11th to 20th	Night	10% 6% 27% 38% 17% 1	652
	21st to end	Night	7% 3 25% 41% 24% 1	630
May	1st to 10th	Night	10% 4 24% 39% 21% 1	630
	11th to 20th	Night	10% 2 20% 38% 26% 4	621
	21st to end	Night	7% 2 11% 40% 35% 5%	683
June	1st to 10th	Night	10% 3 10% 37% 35% 6%	630
	11th to 20th	Night	7% 1 8% 31% 42% 12%	630
	21st to end	Night	7% 2 5% 29% 47% 11%	630
July	1st to 10th	Night	9% 2 3 23% 47% 16%	615
	11th to 20th	Night	7% 1 3 18% 50% 20%	612
	21st to end	Night	6% 1 4 25% 49% 15%	690
August	1st to 10th	Night	11% 2 5% 24% 44% 15%	627
	11th to 20th	Night	9% 1 3 18% 55% 14%	624
	21st to end	Night	12% 2 6% 27% 39% 15%	705
September	1st to 10th	Night	11% 2 7% 29% 40% 10%	840
	11th to 20th	Night	13% 3 9% 34% 36% 5%	840
	21st to end	Night	10% 2 13% 31% 38% 5%	833
October	1st to 10th	Night	13% 2 19% 38% 26% 4	800
	11th to 20th	Night	12% 4 20% 34% 27% 3	800
	21st to end	Night	11% 3 22% 37% 25% 1	880
November	1st to 10th	Night	12% 5% 20% 39% 22% 2	820
	11th to 20th	Night	13% 7% 28% 35% 16% 1	840
	21st to end	Night	14% 7% 30% 33% 17%	840
December	1st to 10th	Night	17% 6% 30% 34% 11% 2	840
	11th to 20th	Night	17% 6% 30% 33% 13% 1	840
	21st to end	Night	20% 8% 26% 35% 11%	924

Page generated at 2026-09-26 04:18:39. Version ac07

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