Seneca City Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Seneca City Park 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	10% 7% 3 7% 4 4 4 3 5% 7% 46%	100936
	Night	10% 7% 3 6% 4 3 4 3 5% 6% 50%	98110
Transparency	Day	37% 6% 13% 25% 17% 2	100748
	Night	34% 5% 12% 26% 19% 3	97969
Seeing	Day	13% 10% 31% 29% 14% 3	15714
	Night	12% 10% 34% 33% 10% 1	25547

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% 12% 4 13% 7% 6% 5% 3 5% 6% 29%	2847
	11th to 20th	Day	8% 11% 4 11% 6% 5% 5% 3 4 5% 37%	2850
	21st to end	Day	9% 12% 6% 13% 5% 3 4 3 4 6% 35%	3135
February	1st to 10th	Day	10% 11% 4 9% 5% 5% 4 4 4 7% 37%	1710
	11th to 20th	Day	9% 8% 3 9% 5% 3 4 3 7% 7% 42%	1721
	21st to end	Day	8% 9% 3 6% 5% 4 4 2 5% 7% 46%	1570
March	1st to 10th	Day	12% 8% 2 6% 3 3 3 3 4 6% 50%	3422
	11th to 20th	Day	9% 9% 2 5% 3 3 3 3 5% 6% 51%	3480
	21st to end	Day	14% 10% 6% 9% 4 5% 4 3 5% 6% 34%	3814
April	1st to 10th	Day	13% 7% 3 6% 4 4 4 3 4 6% 47%	2134
	11th to 20th	Day	12% 8% 3 7% 5% 4 4 4 5% 7% 41%	2326
	21st to end	Day	19% 7% 2 6% 4 3 4 4 6% 7% 38%	2470
May	1st to 10th	Day	13% 9% 3 7% 5% 3 4 4 5% 7% 41%	4082
	11th to 20th	Day	15% 7% 3 6% 4 4 4 3 5% 7% 42%	4082
	21st to end	Day	13% 6% 2 5% 5% 4 4 4 6% 8% 43%	4477
June	1st to 10th	Day	6% 5% 1 5% 4 4 5% 4 6% 9% 52%	2565
	11th to 20th	Day	7% 5% 2 5% 4 4 4 4 6% 9% 49%	2660
	21st to end	Day	7% 5% 2 5% 3 5% 4 4 7% 9% 49%	2501
July	1st to 10th	Day	11% 5% 2 6% 4 4 4 4 6% 9% 44%	4120
	11th to 20th	Day	7% 4 1 5% 4 5% 5% 4 6% 9% 51%	4120
	21st to end	Day	5% 4 1 5% 3 4 4 4 6% 9% 54%	4465
August	1st to 10th	Day	7% 4 2 6% 4 4 5% 4 6% 8% 51%	4104
	11th to 20th	Day	12% 5% 2 6% 4 4 4 3 5% 7% 47%	4041
	21st to end	Day	5% 4 2 5% 4 4 4 4 6% 9% 54%	4414
September	1st to 10th	Day	10% 3 1 4 3 4 4 4 5% 6% 55%	2194
	11th to 20th	Day	8% 5% 2 6% 4 4 4 3 4 8% 51%	2090
	21st to end	Day	9% 5% 2 5% 3 3 3 3 4 5% 58%	2090
October	1st to 10th	Day	12% 5% 2 4 3 3 3 3 5% 5% 54%	1948
	11th to 20th	Day	10% 5% 2 5% 3 2 3 3 4 5% 59%	1900
	21st to end	Day	12% 7% 2 5% 3 3 3 3 3 6% 52%	2090
November	1st to 10th	Day	8% 5% 2 5% 3 3 3 3 5% 7% 56%	1747
	11th to 20th	Day	9% 10% 1 5% 3 2 3 2 4 6% 55%	1710
	21st to end	Day	12% 8% 3 5% 3 3 4 3 5% 6% 49%	1549
December	1st to 10th	Day	8% 7% 3 6% 6% 3 3 3 7% 7% 46%	1520
	11th to 20th	Day	8% 10% 4 9% 4 4 4 3 4 6% 44%	1918
	21st to end	Day	14% 13% 6% 16% 5% 4 4 3 5% 6% 25%	3070
January	1st to 10th	Night	8% 9% 4 16% 6% 4 4 3 4 6% 36%	4108
	11th to 20th	Night	8% 8% 4 8% 4 4 7% 4 4 5% 43%	4120
	21st to end	Night	13% 11% 5% 9% 4 3 4 3 4 5% 38%	4532
February	1st to 10th	Night	10% 12% 3 8% 5% 4 5% 3 5% 6% 39%	2470
	11th to 20th	Night	9% 8% 2 6% 6% 4 4 4 5% 6% 45%	2364
	21st to end	Night	9% 8% 3 6% 4 4 3 4 5% 6% 48%	1884
March	1st to 10th	Night	10% 5% 2 5% 4 3 4 4 4 5% 54%	3431
	11th to 20th	Night	10% 8% 2 5% 3 3 3 2 4 6% 56%	3480
	21st to end	Night	15% 11% 4 8% 4 3 4 3 4 6% 39%	3817
April	1st to 10th	Night	11% 5% 1 5% 4 3 4 3 5% 7% 51%	2044
	11th to 20th	Night	11% 8% 3 6% 4 4 3 4 5% 6% 47%	1800
	21st to end	Night	17% 6% 2 5% 3 4 4 3 5% 7% 44%	1710
May	1st to 10th	Night	15% 7% 2 5% 4 4 4 3 5% 6% 44%	2823
	11th to 20th	Night	16% 6% 2 5% 3 2 2 2 4 8% 48%	2823
	21st to end	Night	13% 5% 2 4 3 3 4 4 5% 7% 50%	3090
June	1st to 10th	Night	6% 4 1 4 4 4 4 3 6% 11% 54%	1606
	11th to 20th	Night	6% 4 1 4 3 3 4 5% 6% 10% 54%	1520
	21st to end	Night	5% 3 1 4 3 3 3 3 6% 9% 60%	1667
July	1st to 10th	Night	10% 6% 2 5% 4 4 4 4 6% 7% 49%	2850
	11th to 20th	Night	3 3 1 4 3 3 4 4 6% 8% 61%	2850
	21st to end	Night	5% 3 1 3 3 3 4 3 5% 9% 59%	3098
August	1st to 10th	Night	3 2 2 4 4 4 4 4 6% 9% 59%	2836
	11th to 20th	Night	11% 5% 2 5% 4 3 4 3 5% 7% 49%	2798
	21st to end	Night	5% 4 2 4 3 3 3 3 5% 8% 59%	3249
September	1st to 10th	Night	9% 4 1 4 3 2 4 3 4 7% 59%	1983
	11th to 20th	Night	8% 4 1 4 3 3 3 3 4 7% 58%	2090
	21st to end	Night	7% 4 2 4 4 3 3 3 4 5% 62%	2090
October	1st to 10th	Night	12% 5% 2 4 3 3 3 3 5% 6% 54%	2212
	11th to 20th	Night	12% 6% 1 3 2 2 3 2 3 6% 59%	2280
	21st to end	Night	12% 8% 2 5% 3 3 3 2 4 5% 55%	2508
November	1st to 10th	Night	6% 5% 1 3 3 2 4 3 5% 6% 61%	2350
	11th to 20th	Night	9% 6% 2 4 3 3 3 4 5% 7% 54%	2470
	21st to end	Night	11% 8% 2 4 3 3 3 3 5% 5% 53%	2626
December	1st to 10th	Night	8% 7% 2 5% 5% 4 4 3 6% 6% 50%	2660
	11th to 20th	Night	9% 9% 3 7% 3 3 3 3 5% 6% 48%	3279
	21st to end	Night	16% 14% 7% 12% 4 3 2 2 3 4 33%	4592

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	54% 7% 11% 18% 9% 1	2848
	11th to 20th	Day	50% 5% 13% 20% 12% 1	2850
	21st to end	Day	51% 5% 12% 18% 13% 1	3135
February	1st to 10th	Day	47% 5% 15% 20% 10% 3	1710
	11th to 20th	Day	41% 6% 12% 24% 14% 3	1730
	21st to end	Day	37% 6% 12% 25% 17% 4	1570
March	1st to 10th	Day	35% 6% 9% 22% 24% 4	3422
	11th to 20th	Day	34% 5% 12% 26% 22% 2	3480
	21st to end	Day	48% 8% 16% 21% 6% 1	3814
April	1st to 10th	Day	39% 4 13% 23% 18% 3	2134
	11th to 20th	Day	41% 6% 12% 23% 15% 2	2326
	21st to end	Day	44% 7% 10% 27% 11% 1	2470
May	1st to 10th	Day	42% 8% 11% 24% 13% 3	4120
	11th to 20th	Day	41% 7% 11% 24% 17%	4086
	21st to end	Day	37% 8% 11% 28% 13% 2	4489
June	1st to 10th	Day	27% 9% 14% 32% 16% 2	2565
	11th to 20th	Day	30% 8% 14% 28% 18% 2	2660
	21st to end	Day	28% 8% 16% 28% 16% 4	2501
July	1st to 10th	Day	35% 7% 14% 25% 17% 3	4056
	11th to 20th	Day	29% 7% 12% 33% 18% 2	4051
	21st to end	Day	24% 7% 16% 30% 20% 4	4325
August	1st to 10th	Day	29% 7% 14% 26% 21% 2	4090
	11th to 20th	Day	38% 5% 16% 24% 17% 1	4080
	21st to end	Day	26% 6% 16% 28% 17% 7%	4413
September	1st to 10th	Day	29% 6% 13% 25% 21% 5%	2194
	11th to 20th	Day	32% 6% 12% 25% 23% 2	2090
	21st to end	Day	30% 4 8% 31% 26% 2	2090
October	1st to 10th	Day	31% 6% 11% 24% 26% 2	1948
	11th to 20th	Day	28% 4 8% 26% 27% 7%	1900
	21st to end	Day	35% 4 12% 23% 20% 6%	2090
November	1st to 10th	Day	27% 5% 12% 30% 22% 4	1747
	11th to 20th	Day	32% 3 9% 29% 23% 3	1710
	21st to end	Day	37% 4 10% 27% 20% 2	1549
December	1st to 10th	Day	36% 6% 15% 28% 14% 1	1520
	11th to 20th	Day	41% 5% 14% 28% 11% 1	1915
	21st to end	Day	60% 5% 9% 17% 8% 1	3070
January	1st to 10th	Night	49% 6% 12% 20% 12% 1	4108
	11th to 20th	Night	43% 5% 12% 24% 15% 1	4120
	21st to end	Night	47% 5% 15% 20% 12% 2	4532
February	1st to 10th	Night	45% 5% 12% 19% 15% 4	2470
	11th to 20th	Night	38% 6% 12% 25% 15% 4	2365
	21st to end	Night	35% 5% 11% 22% 20% 8%	1884
March	1st to 10th	Night	32% 6% 10% 25% 24% 4	3431
	11th to 20th	Night	30% 4 9% 27% 24% 5%	3480
	21st to end	Night	45% 8% 17% 22% 6% 1	3817
April	1st to 10th	Night	33% 6% 11% 25% 21% 4	2044
	11th to 20th	Night	37% 6% 9% 28% 17% 3	1800
	21st to end	Night	40% 7% 11% 23% 18% 1	1710
May	1st to 10th	Night	39% 7% 11% 23% 17% 3	2850
	11th to 20th	Night	35% 7% 11% 25% 22%	2824
	21st to end	Night	32% 8% 15% 26% 19% 1	3099
June	1st to 10th	Night	24% 8% 16% 34% 15% 3	1606
	11th to 20th	Night	24% 7% 15% 32% 17% 5%	1520
	21st to end	Night	20% 5% 15% 33% 22% 4	1667
July	1st to 10th	Night	34% 6% 13% 22% 21% 5%	2805
	11th to 20th	Night	20% 5% 14% 31% 27% 3	2796
	21st to end	Night	21% 6% 17% 33% 23% 1	2999
August	1st to 10th	Night	21% 7% 17% 26% 25% 5%	2826
	11th to 20th	Night	34% 6% 14% 26% 19% 2	2825
	21st to end	Night	24% 5% 15% 32% 17% 6%	3249
September	1st to 10th	Night	25% 6% 11% 27% 23% 8%	1983
	11th to 20th	Night	26% 6% 10% 31% 24% 4	2090
	21st to end	Night	25% 4 9% 26% 32% 4	2090
October	1st to 10th	Night	31% 5% 10% 24% 26% 4	2212
	11th to 20th	Night	28% 4 8% 27% 25% 9%	2280
	21st to end	Night	33% 4 10% 24% 25% 4	2508
November	1st to 10th	Night	24% 4 12% 27% 26% 6%	2350
	11th to 20th	Night	29% 5% 11% 29% 22% 4	2470
	21st to end	Night	33% 4 11% 27% 22% 3	2626
December	1st to 10th	Night	34% 6% 12% 29% 17% 1	2660
	11th to 20th	Night	37% 4 11% 32% 15% 1	3281
	21st to end	Night	57% 4 9% 21% 8% 2	4592

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	17% 16% 38% 20% 8% 1	270
	11th to 20th	Day	20% 19% 37% 20% 4	270
	21st to end	Day	15% 12% 44% 26% 3	297
February	1st to 10th	Day	16% 23% 43% 16% 3	270
	11th to 20th	Day	14% 17% 45% 19% 5% 1	270
	21st to end	Day	12% 19% 49% 17% 3	225
March	1st to 10th	Day	15% 14% 47% 22% 3	270
	11th to 20th	Day	25% 17% 33% 19% 6% 1	270
	21st to end	Day	26% 25% 34% 12% 2 1	297
April	1st to 10th	Day	21% 14% 39% 21% 5%	314
	11th to 20th	Day	18% 16% 39% 22% 5%	524
	21st to end	Day	22% 17% 31% 19% 9% 1	650
May	1st to 10th	Day	18% 13% 38% 23% 8% 1	653
	11th to 20th	Day	19% 12% 29% 27% 12% 3	675
	21st to end	Day	18% 11% 29% 27% 12% 2	734
June	1st to 10th	Day	4 4 26% 33% 26% 6%	680
	11th to 20th	Day	8% 4 34% 34% 17% 3	680
	21st to end	Day	7% 7% 36% 35% 12% 2	680
July	1st to 10th	Day	9% 4 17% 35% 26% 9%	671
	11th to 20th	Day	5% 4 21% 42% 22% 6%	668
	21st to end	Day	7% 2 18% 40% 28% 6%	739
August	1st to 10th	Day	8% 3 18% 41% 27% 4	676
	11th to 20th	Day	9% 3 21% 42% 22% 4	665
	21st to end	Day	10% 3 18% 32% 31% 5%	682
September	1st to 10th	Day	11% 3 20% 41% 22% 3	404
	11th to 20th	Day	6% 5% 23% 40% 21% 5%	300
	21st to end	Day	14% 7% 31% 31% 15% 1	300
October	1st to 10th	Day	18% 8% 26% 27% 16% 5%	300
	11th to 20th	Day	8% 16% 42% 24% 7% 2	300
	21st to end	Day	17% 17% 37% 21% 7% 2	330
November	1st to 10th	Day	12% 13% 40% 23% 11% 1	273
	11th to 20th	Day	16% 17% 40% 22% 6%	270
	21st to end	Day	20% 11% 35% 24% 8% 1	270
December	1st to 10th	Day	9% 13% 42% 28% 6% 1	270
	11th to 20th	Day	17% 17% 33% 28% 6%	270
	21st to end	Day	21% 17% 42% 18% 3	297
January	1st to 10th	Night	11% 14% 39% 30% 7%	950
	11th to 20th	Night	12% 15% 40% 28% 5% 1	950
	21st to end	Night	14% 10% 43% 28% 4	1045
February	1st to 10th	Night	15% 11% 45% 25% 3	950
	11th to 20th	Night	15% 13% 40% 28% 4	890
	21st to end	Night	15% 13% 44% 22% 4	628
March	1st to 10th	Night	13% 15% 43% 24% 5%	582
	11th to 20th	Night	18% 12% 37% 28% 5%	570
	21st to end	Night	24% 13% 39% 19% 4	627
April	1st to 10th	Night	14% 12% 47% 22% 5%	570
	11th to 20th	Night	16% 15% 39% 27% 3	563
	21st to end	Night	19% 11% 39% 25% 6% 1	570
May	1st to 10th	Night	16% 11% 34% 31% 8%	570
	11th to 20th	Night	16% 8% 31% 35% 10% 1	561
	21st to end	Night	14% 6% 30% 36% 13%	617
June	1st to 10th	Night	6% 6% 24% 43% 20% 1	570
	11th to 20th	Night	8% 3 31% 44% 15%	570
	21st to end	Night	5% 4 35% 45% 11%	570
July	1st to 10th	Night	6% 3 19% 46% 26% 1	555
	11th to 20th	Night	3 2 20% 51% 22% 2	552
	21st to end	Night	6% 2 15% 50% 26% 1	624
August	1st to 10th	Night	4 1 20% 49% 25% 2	567
	11th to 20th	Night	7% 2 16% 49% 23% 2	564
	21st to end	Night	7% 2 18% 44% 26% 3	627
September	1st to 10th	Night	11% 3 24% 42% 19% 2	570
	11th to 20th	Night	9% 2 28% 41% 18% 2	570
	21st to end	Night	8% 6% 32% 38% 15% 1	570
October	1st to 10th	Night	14% 7% 30% 34% 13% 2	692
	11th to 20th	Night	15% 9% 40% 28% 8%	760
	21st to end	Night	18% 12% 34% 29% 7%	836
November	1st to 10th	Night	9% 12% 34% 34% 11%	862
	11th to 20th	Night	11% 13% 41% 28% 6%	950
	21st to end	Night	15% 12% 36% 30% 7%	950
December	1st to 10th	Night	12% 14% 38% 29% 6% 1	950
	11th to 20th	Night	16% 12% 39% 28% 5%	950
	21st to end	Night	16% 16% 38% 25% 5%	1045

Page generated at 2024-10-30 00:22:54. Version ac07

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