Owego
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Owego clear sky chart from 2005-11-06 to 2024-11-10.

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% 4 8% 5% 5% 5% 4 6% 7% 31%	101528
	Night	17% 11% 4 8% 5% 4 4 4 5% 6% 31%	97611
Transparency	Day	51% 6% 12% 20% 10% 1	105077
	Night	52% 6% 12% 19% 9% 1	102138
Seeing	Day	24% 17% 29% 18% 9% 3	14755
	Night	22% 15% 28% 25% 9% 1	23991

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% 18% 8% 10% 5% 4 4 3 4 5% 23%	2517
	11th to 20th	Day	14% 15% 8% 17% 7% 5% 4 3 4 4 19%	2552
	21st to end	Day	18% 19% 9% 11% 7% 5% 4 2 4 4 17%	3124
February	1st to 10th	Day	16% 15% 6% 13% 8% 5% 5% 4 4 5% 20%	1710
	11th to 20th	Day	12% 15% 6% 13% 7% 5% 5% 4 4 5% 23%	1705
	21st to end	Day	21% 12% 3 12% 8% 5% 3 4 4 4 25%	1570
March	1st to 10th	Day	24% 15% 5% 10% 5% 4 3 2 3 4 25%	3207
	11th to 20th	Day	12% 18% 5% 8% 6% 4 4 3 4 6% 31%	3480
	21st to end	Day	19% 12% 4 9% 5% 4 4 4 4 5% 31%	3972
April	1st to 10th	Day	18% 15% 3 6% 5% 4 5% 3 5% 6% 31%	2280
	11th to 20th	Day	18% 10% 3 7% 5% 4 5% 3 4 6% 34%	2254
	21st to end	Day	19% 11% 3 7% 4 4 5% 3 3 7% 35%	2282
May	1st to 10th	Day	25% 9% 3 6% 4 4 4 3 5% 6% 32%	4318
	11th to 20th	Day	21% 8% 3 7% 5% 5% 6% 4 6% 7% 27%	4398
	21st to end	Day	13% 6% 2 6% 4 4 5% 4 6% 8% 42%	4837
June	1st to 10th	Day	17% 8% 2 7% 5% 5% 5% 4 6% 8% 34%	2660
	11th to 20th	Day	15% 6% 2 7% 5% 4 5% 5% 7% 9% 35%	2660
	21st to end	Day	13% 7% 3 6% 5% 5% 5% 4 8% 9% 35%	2660
July	1st to 10th	Day	9% 5% 2 7% 5% 5% 5% 5% 8% 12% 36%	4440
	11th to 20th	Day	8% 5% 2 7% 5% 5% 6% 5% 9% 11% 36%	4440
	21st to end	Day	12% 7% 3 7% 6% 6% 6% 5% 7% 8% 34%	4766
August	1st to 10th	Day	20% 6% 3 7% 5% 5% 5% 4 6% 7% 31%	4104
	11th to 20th	Day	17% 7% 3 8% 4 6% 5% 4 8% 9% 30%	3901
	21st to end	Day	16% 7% 2 6% 4 4 5% 4 7% 9% 37%	4180
September	1st to 10th	Day	17% 6% 3 5% 5% 4 5% 3 5% 7% 40%	2280
	11th to 20th	Day	15% 7% 2 5% 4 4 5% 3 5% 6% 44%	2280
	21st to end	Day	20% 7% 2 6% 5% 4 4 4 6% 7% 34%	2024
October	1st to 10th	Day	17% 8% 3 8% 4 5% 4 4 6% 8% 33%	1900
	11th to 20th	Day	18% 9% 3 8% 6% 5% 4 3 5% 7% 33%	1900
	21st to end	Day	22% 12% 4 7% 5% 5% 4 4 5% 6% 28%	2032
November	1st to 10th	Day	14% 11% 3 7% 4 3 4 3 5% 6% 38%	1752
	11th to 20th	Day	17% 13% 3 9% 6% 4 4 4 5% 6% 30%	1625
	21st to end	Day	19% 14% 5% 8% 5% 5% 4 4 6% 8% 23%	1520
December	1st to 10th	Day	19% 18% 6% 10% 6% 5% 4 3 5% 5% 18%	1520
	11th to 20th	Day	22% 14% 7% 10% 5% 3 3 2 3 5% 25%	1906
	21st to end	Day	26% 20% 6% 10% 6% 4 3 3 3 4 16%	2772
January	1st to 10th	Night	17% 15% 5% 13% 5% 5% 4 3 5% 6% 21%	4429
	11th to 20th	Night	14% 16% 7% 13% 7% 4 4 3 5% 6% 20%	4404
	21st to end	Night	24% 15% 6% 13% 8% 5% 4 3 3 4 16%	4532
February	1st to 10th	Night	16% 14% 4 10% 7% 5% 6% 4 5% 6% 24%	2470
	11th to 20th	Night	14% 13% 5% 12% 7% 5% 6% 4 5% 5% 23%	2360
	21st to end	Night	18% 11% 4 12% 6% 5% 5% 3 5% 6% 25%	1884
March	1st to 10th	Night	21% 14% 5% 9% 5% 3 4 3 4 4 29%	3631
	11th to 20th	Night	15% 18% 4 8% 6% 4 4 3 4 6% 28%	3479
	21st to end	Night	16% 13% 4 10% 5% 4 4 3 4 5% 33%	3659
April	1st to 10th	Night	20% 13% 3 7% 5% 3 4 4 4 7% 31%	1900
	11th to 20th	Night	21% 9% 3 6% 4 3 4 3 5% 6% 35%	1875
	21st to end	Night	18% 9% 2 6% 3 4 5% 4 5% 5% 39%	1900
May	1st to 10th	Night	27% 8% 2 7% 4 4 3 3 5% 5% 31%	2635
	11th to 20th	Night	20% 8% 3 7% 5% 3 5% 4 6% 5% 33%	2495
	21st to end	Night	12% 6% 2 7% 6% 5% 5% 4 6% 8% 39%	2738
June	1st to 10th	Night	16% 6% 2 6% 5% 4 5% 3 5% 8% 38%	1520
	11th to 20th	Night	14% 7% 2 5% 4 5% 4 3 6% 9% 40%	1520
	21st to end	Night	12% 5% 2 6% 4 5% 5% 4 6% 8% 44%	1520
July	1st to 10th	Night	9% 6% 3 9% 6% 5% 5% 4 6% 8% 40%	2520
	11th to 20th	Night	11% 4 2 6% 5% 5% 4 4 7% 10% 43%	2520
	21st to end	Night	13% 5% 2 7% 5% 5% 6% 4 5% 7% 40%	2784
August	1st to 10th	Night	18% 6% 3 7% 4 5% 5% 4 5% 7% 35%	2825
	11th to 20th	Night	15% 6% 3 7% 5% 4 4 3 5% 6% 41%	2881
	21st to end	Night	13% 6% 2 6% 4 4 4 4 5% 7% 43%	3476
September	1st to 10th	Night	15% 6% 3 6% 4 4 4 3 5% 6% 45%	1900
	11th to 20th	Night	13% 5% 1 6% 4 4 4 3 5% 6% 49%	1900
	21st to end	Night	18% 6% 2 6% 5% 5% 4 3 6% 7% 38%	2153
October	1st to 10th	Night	19% 7% 3 7% 4 4 4 4 6% 6% 36%	2280
	11th to 20th	Night	19% 9% 2 7% 5% 4 3 3 5% 5% 38%	2280
	21st to end	Night	23% 12% 4 7% 4 4 3 3 4 6% 29%	2565
November	1st to 10th	Night	13% 10% 2 8% 5% 4 4 3 4 6% 40%	2531
	11th to 20th	Night	18% 12% 4 7% 5% 4 4 4 5% 6% 31%	2553
	21st to end	Night	15% 14% 4 7% 5% 4 4 4 6% 8% 28%	2660
December	1st to 10th	Night	19% 15% 6% 9% 6% 6% 4 4 6% 6% 21%	2660
	11th to 20th	Night	21% 14% 5% 10% 5% 5% 5% 4 5% 5% 23%	3288
	21st to end	Night	26% 16% 4 9% 4 4 4 3 5% 5% 19%	4884

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	63% 4 13% 15% 4	2518
	11th to 20th	Day	69% 6% 9% 11% 5% 1	2552
	21st to end	Day	72% 4 10% 10% 3	3124
February	1st to 10th	Day	66% 5% 10% 13% 6% 1	1710
	11th to 20th	Day	63% 5% 9% 17% 6%	1714
	21st to end	Day	62% 5% 9% 17% 7% 1	1570
March	1st to 10th	Day	64% 4 9% 18% 5% 1	3210
	11th to 20th	Day	54% 6% 12% 18% 9% 2	3480
	21st to end	Day	56% 5% 7% 19% 12% 1	3972
April	1st to 10th	Day	54% 6% 8% 21% 9% 2	2280
	11th to 20th	Day	51% 5% 11% 18% 13% 1	2254
	21st to end	Day	51% 5% 9% 19% 13% 3	2282
May	1st to 10th	Day	53% 6% 9% 19% 11% 2	4331
	11th to 20th	Day	54% 9% 10% 19% 7% 1	4402
	21st to end	Day	38% 7% 13% 26% 15% 1	4837
June	1st to 10th	Day	47% 7% 11% 21% 14%	2660
	11th to 20th	Day	43% 8% 15% 22% 11% 1	2660
	21st to end	Day	43% 8% 14% 23% 11% 1	2660
July	1st to 10th	Day	38% 8% 18% 25% 10% 1	4370
	11th to 20th	Day	37% 9% 17% 26% 11%	4365
	21st to end	Day	45% 8% 15% 20% 12% 1	4614
August	1st to 10th	Day	50% 8% 13% 18% 10%	4091
	11th to 20th	Day	48% 8% 15% 22% 7%	3940
	21st to end	Day	43% 7% 11% 32% 8% 1	4180
September	1st to 10th	Day	43% 7% 12% 25% 13% 1	2280
	11th to 20th	Day	40% 6% 11% 24% 18% 1	2280
	21st to end	Day	48% 6% 12% 22% 11% 1	2024
October	1st to 10th	Day	45% 6% 12% 23% 14% 1	3160
	11th to 20th	Day	46% 5% 11% 22% 15% 1	3140
	21st to end	Day	41% 5% 16% 27% 10% 1	3322
November	1st to 10th	Day	46% 6% 13% 21% 12% 2	1752
	11th to 20th	Day	55% 4 13% 18% 8% 2	1625
	21st to end	Day	59% 6% 15% 15% 4	1520
December	1st to 10th	Day	66% 6% 13% 11% 4	1520
	11th to 20th	Day	65% 5% 14% 12% 4	1906
	21st to end	Day	74% 5% 8% 10% 3	2772
January	1st to 10th	Night	64% 4 15% 12% 4	4429
	11th to 20th	Night	64% 6% 12% 13% 4	4404
	21st to end	Night	74% 4 7% 11% 3	4532
February	1st to 10th	Night	59% 6% 12% 15% 7%	2470
	11th to 20th	Night	62% 6% 11% 14% 6% 1	2362
	21st to end	Night	59% 5% 12% 15% 8% 1	1884
March	1st to 10th	Night	60% 4 10% 18% 8%	3641
	11th to 20th	Night	56% 6% 12% 20% 6%	3480
	21st to end	Night	53% 5% 8% 22% 10% 2	3659
April	1st to 10th	Night	54% 6% 9% 19% 10% 2	1900
	11th to 20th	Night	50% 5% 11% 18% 15%	1875
	21st to end	Night	47% 5% 11% 20% 14% 3	1900
May	1st to 10th	Night	54% 7% 8% 20% 9% 2	2641
	11th to 20th	Night	49% 10% 14% 18% 8% 1	2496
	21st to end	Night	41% 9% 13% 19% 17% 1	2739
June	1st to 10th	Night	42% 7% 12% 24% 15% 1	1520
	11th to 20th	Night	40% 9% 14% 24% 12% 1	1520
	21st to end	Night	38% 8% 14% 27% 13% 1	1520
July	1st to 10th	Night	41% 7% 13% 22% 15% 1	2480
	11th to 20th	Night	36% 7% 17% 26% 15%	2472
	21st to end	Night	41% 9% 11% 21% 16% 1	2695
August	1st to 10th	Night	47% 9% 14% 22% 8%	2814
	11th to 20th	Night	43% 7% 15% 26% 10%	2908
	21st to end	Night	38% 6% 13% 31% 11% 1	3476
September	1st to 10th	Night	39% 7% 13% 25% 14% 2	1900
	11th to 20th	Night	35% 6% 13% 27% 18% 1	1900
	21st to end	Night	45% 7% 11% 22% 14% 1	2153
October	1st to 10th	Night	50% 6% 11% 21% 11% 1	3800
	11th to 20th	Night	42% 5% 13% 22% 15% 3	3779
	21st to end	Night	42% 4 15% 27% 10% 1	4213
November	1st to 10th	Night	46% 6% 13% 21% 14% 2	2531
	11th to 20th	Night	52% 7% 12% 19% 9% 2	2553
	21st to end	Night	54% 7% 17% 18% 5%	2660
December	1st to 10th	Night	63% 7% 14% 13% 4	2660
	11th to 20th	Night	63% 6% 11% 14% 5%	3288
	21st to end	Night	67% 6% 12% 13% 2	4884

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% 22% 34% 12% 3 1	180
	11th to 20th	Day	36% 28% 29% 6% 1 1	189
	21st to end	Day	24% 33% 29% 10% 4	297
February	1st to 10th	Day	30% 33% 30% 7% 1	270
	11th to 20th	Day	34% 33% 27% 5% 1	312
	21st to end	Day	35% 22% 31% 9% 2	382
March	1st to 10th	Day	32% 21% 30% 13% 4	460
	11th to 20th	Day	33% 23% 26% 13% 4	460
	21st to end	Day	31% 26% 27% 10% 3 2	506
April	1st to 10th	Day	34% 20% 28% 13% 4 1	460
	11th to 20th	Day	27% 27% 25% 11% 6% 3	452
	21st to end	Day	31% 18% 28% 16% 5% 2	460
May	1st to 10th	Day	29% 18% 30% 12% 7% 3	463
	11th to 20th	Day	22% 15% 31% 18% 9% 3	487
	21st to end	Day	17% 13% 29% 24% 13% 4	529
June	1st to 10th	Day	17% 16% 33% 21% 11% 2	490
	11th to 20th	Day	17% 13% 27% 27% 13% 2	490
	21st to end	Day	17% 14% 34% 24% 9% 3	490
July	1st to 10th	Day	12% 8% 29% 29% 16% 6%	485
	11th to 20th	Day	10% 8% 27% 32% 17% 5%	484
	21st to end	Day	14% 8% 35% 28% 13% 3	532
August	1st to 10th	Day	12% 9% 28% 26% 19% 7%	486
	11th to 20th	Day	16% 9% 25% 28% 15% 8%	479
	21st to end	Day	14% 10% 28% 25% 13% 11%	539
September	1st to 10th	Day	18% 12% 22% 24% 16% 8%	490
	11th to 20th	Day	15% 9% 23% 22% 20% 11%	490
	21st to end	Day	23% 13% 27% 20% 12% 5%	490
October	1st to 10th	Day	22% 14% 26% 17% 14% 6%	490
	11th to 20th	Day	23% 17% 29% 22% 7% 2	490
	21st to end	Day	32% 17% 29% 16% 6%	508
November	1st to 10th	Day	23% 20% 25% 20% 10% 2	392
	11th to 20th	Day	32% 18% 28% 16% 6%	285
	21st to end	Day	34% 22% 33% 7% 3	180
December	1st to 10th	Day	36% 19% 30% 12% 2 1	180
	11th to 20th	Day	37% 23% 27% 11% 2	180
	21st to end	Day	34% 24% 33% 8% 1	198
January	1st to 10th	Night	23% 25% 33% 16% 2	760
	11th to 20th	Night	26% 21% 30% 20% 3	760
	21st to end	Night	20% 24% 34% 19% 3	836
February	1st to 10th	Night	26% 20% 33% 19% 2	760
	11th to 20th	Night	27% 23% 33% 15% 1	743
	21st to end	Night	30% 22% 29% 16% 3	628
March	1st to 10th	Night	26% 23% 28% 20% 3	760
	11th to 20th	Night	27% 20% 32% 18% 4	760
	21st to end	Night	26% 21% 29% 18% 6% 1	836
April	1st to 10th	Night	28% 19% 31% 20% 3	760
	11th to 20th	Night	27% 16% 32% 18% 7%	751
	21st to end	Night	24% 14% 33% 24% 6%	760
May	1st to 10th	Night	25% 12% 25% 31% 8%	462
	11th to 20th	Night	17% 11% 33% 31% 8% 1	374
	21st to end	Night	14% 10% 27% 33% 15%	411
June	1st to 10th	Night	16% 9% 28% 34% 13%	380
	11th to 20th	Night	16% 8% 24% 35% 16% 1	380
	21st to end	Night	12% 5% 28% 44% 11% 1	380
July	1st to 10th	Night	8% 4 22% 45% 19% 2	370
	11th to 20th	Night	10% 4 21% 46% 18% 1	368
	21st to end	Night	14% 5% 17% 45% 18% 1	437
August	1st to 10th	Night	12% 3 22% 37% 25% 2	567
	11th to 20th	Night	14% 5% 17% 34% 27% 3	621
	21st to end	Night	14% 5% 19% 35% 26% 2	836
September	1st to 10th	Night	16% 6% 26% 31% 19% 2	760
	11th to 20th	Night	14% 6% 21% 30% 24% 5%	760
	21st to end	Night	19% 10% 24% 26% 18% 2	760
October	1st to 10th	Night	22% 9% 25% 25% 16% 2	760
	11th to 20th	Night	23% 14% 27% 27% 7% 1	760
	21st to end	Night	30% 14% 29% 22% 5%	836
November	1st to 10th	Night	20% 14% 32% 26% 8% 1	779
	11th to 20th	Night	26% 17% 32% 18% 6% 1	760
	21st to end	Night	23% 18% 33% 21% 4	760
December	1st to 10th	Night	28% 21% 29% 18% 4	760
	11th to 20th	Night	26% 22% 30% 19% 3	760
	21st to end	Night	29% 19% 33% 17% 2	836

Page generated at 2024-11-07 06:55:42. Version ac07

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