Onondaga Cave State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Onondaga Cave State Park clear sky chart from 2005-11-06 to 2024-11-04.

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	12% 7% 3 6% 4 4 4 4 5% 7% 43%	101177
	Night	13% 8% 3 6% 4 4 4 3 5% 6% 44%	97917
Transparency	Day	38% 6% 11% 24% 17% 3	104812
	Night	38% 5% 11% 24% 18% 3	102423
Seeing	Day	17% 12% 28% 25% 14% 4	15596
	Night	17% 12% 30% 27% 12% 1	25388

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	11% 13% 5% 10% 5% 3 4 3 5% 5% 35%	2559
	11th to 20th	Day	12% 11% 4 9% 4 5% 3 3 4 6% 40%	2850
	21st to end	Day	21% 13% 5% 6% 3 3 3 3 4 5% 34%	3135
February	1st to 10th	Day	14% 12% 4 8% 5% 5% 4 3 4 6% 35%	1710
	11th to 20th	Day	15% 10% 3 7% 5% 4 4 4 5% 5% 38%	1793
	21st to end	Day	13% 12% 3 7% 5% 3 4 4 5% 7% 38%	1570
March	1st to 10th	Day	19% 11% 3 7% 4 3 3 2 3 4 42%	3276
	11th to 20th	Day	14% 7% 2 3 3 3 3 3 4 6% 51%	3480
	21st to end	Day	15% 9% 3 7% 5% 5% 5% 4 5% 7% 35%	3958
April	1st to 10th	Day	11% 6% 2 6% 4 4 4 3 6% 8% 45%	2280
	11th to 20th	Day	17% 8% 2 6% 4 4 4 3 5% 6% 41%	2254
	21st to end	Day	20% 8% 3 7% 5% 4 4 3 5% 7% 35%	2280
May	1st to 10th	Day	14% 7% 3 6% 5% 5% 6% 4 7% 9% 32%	3787
	11th to 20th	Day	18% 7% 2 6% 3 4 5% 3 5% 8% 39%	4353
	21st to end	Day	11% 6% 3 7% 5% 5% 4 3 5% 7% 43%	4824
June	1st to 10th	Day	9% 5% 2 6% 4 5% 5% 5% 6% 8% 45%	2660
	11th to 20th	Day	7% 4 2 4 4 4 5% 4 6% 9% 49%	2660
	21st to end	Day	6% 3 1 4 5% 5% 5% 5% 8% 10% 47%	2660
July	1st to 10th	Day	14% 5% 2 6% 4 4 5% 4 7% 8% 41%	4440
	11th to 20th	Day	5% 4 2 5% 4 5% 5% 5% 6% 10% 49%	4357
	21st to end	Day	9% 5% 2 7% 6% 5% 6% 5% 8% 10% 38%	4465
August	1st to 10th	Day	6% 3 1 5% 4 4 5% 4 7% 10% 52%	4104
	11th to 20th	Day	12% 5% 2 6% 4 5% 5% 4 5% 7% 45%	3764
	21st to end	Day	7% 4 2 5% 4 4 5% 4 6% 8% 52%	4180
September	1st to 10th	Day	13% 5% 2 4 4 3 4 3 6% 8% 49%	2280
	11th to 20th	Day	11% 5% 2 6% 3 3 4 3 6% 6% 50%	2280
	21st to end	Day	9% 5% 3 5% 3 4 4 4 5% 6% 52%	2035
October	1st to 10th	Day	10% 5% 2 5% 4 3 3 2 4 6% 58%	1900
	11th to 20th	Day	15% 6% 2 4 3 2 3 3 3 5% 54%	1900
	21st to end	Day	17% 8% 2 5% 3 3 3 3 4 5% 47%	2090
November	1st to 10th	Day	11% 6% 1 5% 3 3 3 3 4 5% 55%	1751
	11th to 20th	Day	14% 8% 3 5% 4 3 4 2 6% 6% 46%	1710
	21st to end	Day	15% 10% 2 7% 3 3 3 3 4 5% 44%	1611
December	1st to 10th	Day	14% 12% 2 5% 4 3 4 3 5% 7% 41%	1520
	11th to 20th	Day	13% 11% 4 7% 4 4 3 2 5% 6% 39%	1918
	21st to end	Day	15% 16% 6% 8% 5% 4 4 3 5% 6% 28%	2783
January	1st to 10th	Night	13% 11% 6% 10% 5% 4 4 3 4 5% 36%	4392
	11th to 20th	Night	13% 9% 5% 12% 5% 6% 6% 3 4 5% 32%	4120
	21st to end	Night	23% 15% 5% 7% 4 3 3 2 3 4 32%	4532
February	1st to 10th	Night	17% 12% 4 8% 4 3 3 3 5% 5% 37%	2470
	11th to 20th	Night	13% 8% 4 8% 4 4 3 3 4 6% 42%	2271
	21st to end	Night	17% 10% 2 9% 4 3 3 3 5% 4 39%	1884
March	1st to 10th	Night	21% 11% 2 5% 3 3 2 2 3 4 43%	3605
	11th to 20th	Night	14% 6% 2 4 3 3 4 3 4 6% 50%	3480
	21st to end	Night	16% 11% 3 7% 6% 5% 3 4 6% 6% 32%	3672
April	1st to 10th	Night	10% 7% 2 6% 4 3 3 3 5% 8% 49%	1900
	11th to 20th	Night	14% 9% 2 5% 4 3 4 4 4 6% 46%	1875
	21st to end	Night	20% 6% 3 6% 4 4 3 3 5% 6% 41%	1900
May	1st to 10th	Night	19% 6% 2 6% 4 3 3 3 5% 7% 42%	3106
	11th to 20th	Night	15% 7% 3 6% 3 4 4 3 5% 7% 44%	2549
	21st to end	Night	11% 7% 2 7% 5% 5% 5% 4 6% 8% 40%	2743
June	1st to 10th	Night	8% 4 2 5% 5% 5% 4 4 6% 9% 48%	1520
	11th to 20th	Night	6% 3 2 3 3 2 4 4 6% 12% 55%	1520
	21st to end	Night	4 3 1 3 3 5% 3 5% 7% 9% 58%	1520
July	1st to 10th	Night	13% 5% 2 5% 4 4 3 4 5% 10% 46%	2530
	11th to 20th	Night	6% 3 1 3 3 3 3 3 6% 8% 60%	2609
	21st to end	Night	7% 5% 2 6% 5% 5% 5% 4 6% 10% 44%	3098
August	1st to 10th	Night	5% 2 1 4 3 4 4 3 5% 8% 60%	2836
	11th to 20th	Night	11% 4 2 6% 4 3 4 4 5% 8% 49%	3063
	21st to end	Night	6% 3 1 4 3 3 4 3 5% 8% 59%	3476
September	1st to 10th	Night	12% 6% 2 5% 4 3 3 2 5% 6% 53%	1900
	11th to 20th	Night	9% 5% 2 5% 5% 3 4 4 5% 7% 53%	1900
	21st to end	Night	10% 4 2 5% 3 4 4 3 4 6% 55%	2121
October	1st to 10th	Night	8% 3 1 4 3 2 3 3 4 7% 61%	2280
	11th to 20th	Night	15% 5% 1 4 3 2 3 2 4 5% 54%	2280
	21st to end	Night	19% 7% 2 4 3 3 3 2 4 5% 48%	2508
November	1st to 10th	Night	11% 6% 2 4 3 3 2 3 5% 5% 57%	2399
	11th to 20th	Night	14% 7% 3 4 4 3 3 2 4 7% 49%	2470
	21st to end	Night	16% 10% 2 5% 4 3 3 2 4 6% 44%	2565
December	1st to 10th	Night	15% 11% 4 6% 5% 3 4 3 5% 7% 38%	2660
	11th to 20th	Night	15% 11% 4 7% 4 4 3 3 4 4 41%	3279
	21st to end	Night	16% 19% 5% 10% 5% 4 5% 4 4 5% 24%	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	47% 6% 10% 24% 11% 2	2560
	11th to 20th	Day	45% 5% 8% 24% 16% 1	2850
	21st to end	Day	52% 4 9% 17% 14% 4	3135
February	1st to 10th	Day	51% 4 10% 22% 12% 1	1710
	11th to 20th	Day	47% 5% 11% 19% 15% 5%	1803
	21st to end	Day	45% 5% 8% 23% 14% 5%	1570
March	1st to 10th	Day	47% 5% 7% 19% 15% 8%	3276
	11th to 20th	Day	35% 5% 11% 27% 15% 7%	3480
	21st to end	Day	45% 10% 16% 19% 10% 1	3958
April	1st to 10th	Day	36% 7% 12% 24% 19% 2	2280
	11th to 20th	Day	43% 6% 11% 21% 16% 3	2254
	21st to end	Day	48% 7% 11% 21% 12% 1	2280
May	1st to 10th	Day	43% 11% 14% 20% 12% 1	3822
	11th to 20th	Day	43% 8% 11% 24% 13% 1	4357
	21st to end	Day	38% 8% 11% 22% 20% 1	4837
June	1st to 10th	Day	34% 9% 14% 26% 16% 2	2660
	11th to 20th	Day	28% 8% 13% 28% 20% 3	2660
	21st to end	Day	28% 9% 18% 26% 15% 5%	2660
July	1st to 10th	Day	39% 6% 12% 29% 12% 2	4371
	11th to 20th	Day	29% 6% 14% 33% 16% 2	4282
	21st to end	Day	40% 5% 18% 27% 8% 1	4325
August	1st to 10th	Day	27% 6% 16% 32% 18%	4090
	11th to 20th	Day	39% 5% 12% 25% 17% 2	3800
	21st to end	Day	30% 4 15% 35% 13% 3	4179
September	1st to 10th	Day	33% 7% 11% 26% 18% 5%	2280
	11th to 20th	Day	35% 6% 8% 26% 25% 2	2280
	21st to end	Day	32% 6% 8% 27% 24% 3	2035
October	1st to 10th	Day	17% 3 6% 19% 45% 9%	3160
	11th to 20th	Day	23% 2 6% 21% 37% 10%	3140
	21st to end	Day	31% 3 7% 30% 26% 3	3428
November	1st to 10th	Day	33% 4 11% 24% 23% 6%	1751
	11th to 20th	Day	38% 3 9% 23% 22% 5%	1710
	21st to end	Day	42% 4 9% 26% 17% 1	1611
December	1st to 10th	Day	43% 6% 11% 27% 12% 2	1520
	11th to 20th	Day	47% 5% 9% 19% 20% 1	1915
	21st to end	Day	56% 7% 11% 15% 10% 2	2783
January	1st to 10th	Night	51% 5% 10% 21% 12% 1	4392
	11th to 20th	Night	53% 6% 9% 20% 10% 2	4120
	21st to end	Night	57% 4 9% 20% 9% 1	4532
February	1st to 10th	Night	50% 5% 10% 20% 14% 2	2470
	11th to 20th	Night	44% 5% 10% 22% 17% 3	2272
	21st to end	Night	46% 5% 10% 20% 15% 4	1884
March	1st to 10th	Night	46% 4 8% 22% 16% 4	3605
	11th to 20th	Night	35% 6% 11% 24% 19% 5%	3480
	21st to end	Night	48% 9% 13% 23% 7%	3672
April	1st to 10th	Night	33% 6% 12% 27% 19% 3	1900
	11th to 20th	Night	39% 5% 11% 23% 17% 5%	1875
	21st to end	Night	44% 6% 9% 24% 16% 1	1900
May	1st to 10th	Night	40% 8% 16% 20% 13% 2	3136
	11th to 20th	Night	39% 8% 13% 25% 14% 1	2550
	21st to end	Night	38% 11% 13% 22% 14% 1	2751
June	1st to 10th	Night	31% 8% 16% 25% 17% 3	1520
	11th to 20th	Night	22% 8% 14% 29% 23% 4	1520
	21st to end	Night	20% 8% 18% 28% 19% 7%	1520
July	1st to 10th	Night	35% 5% 15% 27% 15% 3	2490
	11th to 20th	Night	21% 5% 12% 39% 20% 2	2561
	21st to end	Night	36% 6% 17% 26% 13% 2	2999
August	1st to 10th	Night	22% 6% 19% 31% 21% 1	2826
	11th to 20th	Night	33% 6% 16% 26% 16% 3	3093
	21st to end	Night	24% 4 16% 37% 17% 3	3476
September	1st to 10th	Night	32% 5% 10% 26% 22% 6%	1900
	11th to 20th	Night	30% 5% 11% 24% 27% 2	1900
	21st to end	Night	30% 6% 9% 24% 27% 3	2121
October	1st to 10th	Night	14% 3 7% 17% 50% 10%	3800
	11th to 20th	Night	22% 2 7% 21% 35% 13%	3779
	21st to end	Night	32% 2 7% 27% 27% 4	4120
November	1st to 10th	Night	31% 4 12% 26% 22% 6%	2399
	11th to 20th	Night	37% 4 8% 23% 23% 5%	2470
	21st to end	Night	43% 4 9% 24% 18% 2	2565
December	1st to 10th	Night	46% 5% 11% 23% 14% 2	2660
	11th to 20th	Night	46% 5% 9% 23% 15% 1	3281
	21st to end	Night	60% 7% 9% 13% 8% 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	24% 24% 34% 16% 2	270
	11th to 20th	Day	31% 20% 37% 11%	270
	21st to end	Day	22% 30% 35% 11% 2	297
February	1st to 10th	Day	26% 26% 31% 16% 1	270
	11th to 20th	Day	28% 27% 31% 11% 1 1	270
	21st to end	Day	30% 24% 35% 10% 1	225
March	1st to 10th	Day	21% 27% 41% 10% 1	270
	11th to 20th	Day	32% 21% 31% 12% 3 1	270
	21st to end	Day	33% 20% 33% 12% 2	377
April	1st to 10th	Day	21% 18% 37% 17% 6%	460
	11th to 20th	Day	27% 17% 30% 20% 6% 1	452
	21st to end	Day	23% 18% 34% 19% 5% 1	460
May	1st to 10th	Day	22% 17% 34% 20% 6% 1	472
	11th to 20th	Day	18% 13% 27% 28% 11% 2	675
	21st to end	Day	13% 8% 37% 25% 13% 5%	734
June	1st to 10th	Day	10% 6% 25% 28% 25% 5%	680
	11th to 20th	Day	8% 4 26% 37% 21% 4	680
	21st to end	Day	5% 8% 29% 37% 17% 4	680
July	1st to 10th	Day	15% 4 15% 30% 28% 9%	671
	11th to 20th	Day	4 4 21% 38% 27% 6%	668
	21st to end	Day	10% 4 17% 36% 26% 7%	739
August	1st to 10th	Day	9% 1 20% 39% 24% 7%	676
	11th to 20th	Day	12% 3 21% 33% 24% 8%	502
	21st to end	Day	11% 1 16% 31% 33% 8%	539
September	1st to 10th	Day	13% 4 16% 33% 26% 8%	490
	11th to 20th	Day	9% 3 19% 33% 25% 12%	490
	21st to end	Day	11% 9% 24% 32% 17% 7%	423
October	1st to 10th	Day	12% 11% 29% 31% 12% 5%	300
	11th to 20th	Day	19% 17% 33% 22% 7% 1	300
	21st to end	Day	30% 19% 29% 18% 4	330
November	1st to 10th	Day	15% 13% 42% 18% 10% 2	279
	11th to 20th	Day	23% 18% 34% 16% 8% 1	270
	21st to end	Day	27% 18% 30% 21% 4	270
December	1st to 10th	Day	19% 25% 33% 14% 6% 3	270
	11th to 20th	Day	24% 21% 36% 15% 3 1	270
	21st to end	Day	28% 23% 36% 11% 2	297
January	1st to 10th	Night	21% 21% 36% 18% 3	950
	11th to 20th	Night	23% 24% 32% 17% 3	950
	21st to end	Night	21% 20% 38% 21% 1	1045
February	1st to 10th	Night	23% 19% 38% 18% 2	950
	11th to 20th	Night	20% 19% 41% 18% 2	796
	21st to end	Night	26% 21% 35% 17% 1	628
March	1st to 10th	Night	24% 16% 39% 18% 2	684
	11th to 20th	Night	24% 14% 38% 21% 3	570
	21st to end	Night	26% 16% 33% 20% 4	627
April	1st to 10th	Night	15% 17% 40% 24% 4	570
	11th to 20th	Night	18% 16% 34% 27% 5%	563
	21st to end	Night	23% 12% 39% 18% 8%	570
May	1st to 10th	Night	18% 9% 34% 30% 8%	570
	11th to 20th	Night	19% 7% 28% 32% 14% 1	561
	21st to end	Night	12% 7% 28% 35% 16% 3	617
June	1st to 10th	Night	10% 5% 19% 38% 26% 2	570
	11th to 20th	Night	8% 2 25% 43% 21% 2	570
	21st to end	Night	4 2 27% 42% 23% 2	570
July	1st to 10th	Night	11% 1 13% 38% 30% 7%	555
	11th to 20th	Night	4 3 17% 42% 31% 3	552
	21st to end	Night	7% 2 16% 44% 28% 3	624
August	1st to 10th	Night	7% 2 14% 42% 33% 2	567
	11th to 20th	Night	8% 1 18% 38% 32% 3	564
	21st to end	Night	6% 2 15% 35% 37% 5%	627
September	1st to 10th	Night	14% 2 14% 35% 29% 5%	570
	11th to 20th	Night	12% 3 14% 37% 30% 6%	570
	21st to end	Night	10% 7% 24% 30% 24% 5%	727
October	1st to 10th	Night	9% 4 28% 34% 22% 3	760
	11th to 20th	Night	18% 12% 32% 28% 11%	760
	21st to end	Night	23% 14% 32% 24% 7%	836
November	1st to 10th	Night	14% 10% 38% 29% 8% 1	755
	11th to 20th	Night	19% 16% 34% 23% 7%	760
	21st to end	Night	23% 16% 35% 21% 5%	855
December	1st to 10th	Night	23% 15% 37% 20% 4 1	950
	11th to 20th	Night	24% 13% 37% 22% 4	950
	21st to end	Night	26% 19% 35% 19% 2	1045

Page generated at 2024-11-01 21:47:37. Version ac07

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