Cincinnati Nature Center
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Cincinnati Nature Center clear sky chart from 2005-11-06 to 2024-09-29.

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	15% 9% 3 7% 5% 4 4 4 5% 7% 36%	101374
	Night	15% 10% 3 7% 4 4 4 3 5% 7% 37%	96788
Transparency	Day	46% 5% 11% 23% 14% 2	101179
	Night	46% 5% 10% 23% 14% 2	96654
Seeing	Day	19% 13% 27% 22% 13% 6%	15139
	Night	19% 10% 27% 28% 15% 2	24607

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	17% 17% 7% 10% 4 4 4 3 4 5% 26%	2812
	11th to 20th	Day	16% 15% 7% 12% 6% 7% 6% 3 4 4 20%	2840
	21st to end	Day	28% 17% 9% 8% 3 3 3 2 4 5% 19%	3124
February	1st to 10th	Day	20% 13% 5% 8% 5% 4 4 3 4 4 30%	1800
	11th to 20th	Day	17% 11% 5% 11% 5% 4 4 3 4 5% 31%	1848
	21st to end	Day	19% 15% 6% 7% 5% 3 4 3 4 5% 30%	1570
March	1st to 10th	Day	23% 16% 4 9% 4 3 3 3 4 5% 26%	3169
	11th to 20th	Day	15% 8% 3 6% 4 4 4 4 5% 7% 40%	3480
	21st to end	Day	18% 10% 3 7% 4 4 4 3 5% 7% 36%	3815
April	1st to 10th	Day	16% 10% 3 7% 4 4 5% 4 5% 7% 35%	2224
	11th to 20th	Day	17% 8% 3 6% 4 4 4 3 4 7% 39%	2314
	21st to end	Day	17% 9% 3 8% 4 4 4 4 5% 7% 35%	2470
May	1st to 10th	Day	21% 10% 3 8% 5% 4 5% 4 5% 7% 30%	4082
	11th to 20th	Day	20% 8% 3 6% 4 3 4 3 5% 7% 36%	4081
	21st to end	Day	11% 6% 3 7% 5% 5% 6% 5% 8% 10% 34%	4476
June	1st to 10th	Day	12% 6% 2 6% 5% 5% 5% 5% 6% 7% 40%	2470
	11th to 20th	Day	9% 5% 2 6% 5% 4 4 4 7% 9% 44%	2609
	21st to end	Day	9% 6% 2 7% 6% 5% 6% 5% 6% 9% 40%	2660
July	1st to 10th	Day	12% 7% 3 7% 5% 4 5% 4 6% 10% 37%	4440
	11th to 20th	Day	7% 4 1 6% 4 5% 5% 4 7% 11% 46%	4202
	21st to end	Day	11% 7% 3 8% 6% 6% 6% 6% 7% 8% 31%	4466
August	1st to 10th	Day	9% 5% 2 5% 5% 5% 4 5% 7% 11% 42%	4104
	11th to 20th	Day	7% 6% 2 6% 5% 5% 5% 5% 7% 11% 41%	4044
	21st to end	Day	6% 4 2 5% 3 3 4 3 6% 8% 55%	4226
September	1st to 10th	Day	13% 6% 2 5% 3 3 4 4 5% 6% 48%	2152
	11th to 20th	Day	9% 5% 2 5% 3 4 4 4 7% 8% 48%	2090
	21st to end	Day	16% 6% 2 5% 4 4 3 2 4 6% 46%	2069
October	1st to 10th	Day	12% 5% 2 6% 4 5% 4 4 5% 6% 48%	1980
	11th to 20th	Day	14% 7% 2 6% 4 3 4 3 5% 7% 45%	1819
	21st to end	Day	21% 9% 3 6% 3 3 4 3 4 6% 38%	1859
November	1st to 10th	Day	9% 8% 2 5% 4 3 4 3 4 6% 53%	1672
	11th to 20th	Day	14% 12% 4 8% 5% 3 4 3 4 6% 37%	1710
	21st to end	Day	18% 11% 4 8% 4 3 4 3 4 6% 37%	1710
December	1st to 10th	Day	22% 14% 5% 8% 6% 5% 4 3 4 4 26%	1710
	11th to 20th	Day	16% 15% 5% 10% 6% 4 4 3 4 5% 29%	2153
	21st to end	Day	20% 21% 5% 10% 5% 4 4 3 4 5% 18%	3124
January	1st to 10th	Night	16% 19% 6% 11% 5% 4 5% 3 4 5% 22%	4109
	11th to 20th	Night	15% 18% 6% 15% 6% 4 3 3 3 5% 23%	4120
	21st to end	Night	27% 17% 5% 8% 4 4 3 2 3 4 22%	4532
February	1st to 10th	Night	21% 13% 4 9% 4 5% 4 3 5% 5% 28%	2376
	11th to 20th	Night	18% 11% 4 8% 5% 4 5% 3 5% 6% 30%	2218
	21st to end	Night	21% 16% 5% 8% 4 3 3 3 4 6% 29%	1884
March	1st to 10th	Night	21% 15% 2 6% 3 4 4 3 4 6% 33%	3683
	11th to 20th	Night	14% 8% 3 6% 3 4 4 4 5% 6% 43%	3480
	21st to end	Night	16% 10% 3 7% 5% 4 3 4 5% 5% 39%	3817
April	1st to 10th	Night	15% 10% 2 7% 5% 4 5% 3 5% 8% 37%	1971
	11th to 20th	Night	15% 7% 2 6% 4 4 4 4 6% 7% 40%	1815
	21st to end	Night	17% 7% 4 7% 5% 4 4 3 6% 8% 37%	1710
May	1st to 10th	Night	22% 12% 3 8% 4 4 4 4 5% 6% 27%	2813
	11th to 20th	Night	18% 7% 2 5% 4 4 4 4 6% 8% 37%	2812
	21st to end	Night	10% 5% 2 5% 5% 4 4 4 7% 9% 45%	3079
June	1st to 10th	Night	9% 5% 2 4 5% 5% 4 3 6% 9% 48%	1710
	11th to 20th	Night	8% 5% 2 5% 4 4 4 4 6% 11% 49%	1565
	21st to end	Night	6% 5% 2 5% 4 4 6% 4 8% 10% 46%	1520
July	1st to 10th	Night	10% 5% 2 5% 4 4 4 3 6% 8% 49%	2530
	11th to 20th	Night	6% 4 2 5% 4 5% 4 4 5% 9% 51%	2742
	21st to end	Night	11% 6% 2 8% 5% 5% 4 5% 7% 10% 36%	3087
August	1st to 10th	Night	7% 6% 2 7% 5% 4 5% 3 7% 8% 45%	2825
	11th to 20th	Night	9% 7% 2 7% 4 4 4 3 6% 9% 44%	2785
	21st to end	Night	4 2 1 4 3 3 4 3 6% 10% 60%	3426
September	1st to 10th	Night	12% 6% 1 4 3 3 3 3 6% 6% 52%	2009
	11th to 20th	Night	8% 4 2 6% 4 3 5% 3 5% 7% 53%	2090
	21st to end	Night	15% 5% 2 5% 4 4 4 3 4 6% 49%	2079
October	1st to 10th	Night	9% 4 2 6% 4 4 3 3 5% 7% 53%	1980
	11th to 20th	Night	15% 7% 2 6% 4 4 4 4 5% 7% 44%	2139
	21st to end	Night	19% 8% 3 6% 4 3 3 3 4 5% 41%	2492
November	1st to 10th	Night	14% 7% 2 5% 4 3 4 3 5% 6% 47%	2406
	11th to 20th	Night	16% 9% 2 7% 4 3 4 3 4 7% 39%	2470
	21st to end	Night	18% 12% 3 7% 5% 4 4 4 4 6% 34%	2470
December	1st to 10th	Night	21% 13% 5% 8% 5% 4 4 3 5% 5% 29%	2470
	11th to 20th	Night	18% 14% 6% 8% 4 4 3 3 4 6% 29%	3042
	21st to end	Night	20% 19% 6% 10% 6% 5% 4 3 5% 5% 17%	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	61% 4 11% 14% 10%	2813
	11th to 20th	Day	64% 8% 8% 14% 6%	2840
	21st to end	Day	69% 4 8% 16% 4	3124
February	1st to 10th	Day	57% 4 9% 18% 10% 2	1800
	11th to 20th	Day	56% 4 9% 19% 11% 1	1858
	21st to end	Day	56% 4 9% 20% 9% 2	1570
March	1st to 10th	Day	58% 6% 8% 18% 8% 1	3169
	11th to 20th	Day	42% 5% 10% 25% 16% 1	3480
	21st to end	Day	48% 5% 11% 24% 11% 1	3815
April	1st to 10th	Day	47% 5% 10% 24% 13% 1	2224
	11th to 20th	Day	45% 5% 9% 23% 14% 3	2314
	21st to end	Day	49% 5% 11% 22% 12% 2	2470
May	1st to 10th	Day	53% 5% 12% 21% 8% 1	4120
	11th to 20th	Day	47% 6% 13% 22% 12% 1	4085
	21st to end	Day	41% 8% 14% 20% 16% 2	4489
June	1st to 10th	Day	40% 7% 11% 24% 16% 2	2470
	11th to 20th	Day	35% 7% 15% 25% 18% 1	2609
	21st to end	Day	39% 6% 14% 23% 14% 4	2660
July	1st to 10th	Day	41% 6% 11% 21% 19% 1	4371
	11th to 20th	Day	31% 6% 11% 34% 17% 1	4130
	21st to end	Day	47% 7% 13% 19% 13% 2	4324
August	1st to 10th	Day	33% 7% 15% 33% 11% 1	4091
	11th to 20th	Day	35% 6% 12% 32% 15%	4083
	21st to end	Day	26% 5% 15% 30% 21% 3	4225
September	1st to 10th	Day	36% 4 12% 24% 20% 5%	2152
	11th to 20th	Day	31% 5% 12% 26% 22% 3	2090
	21st to end	Day	40% 3 9% 25% 21% 2	2069
October	1st to 10th	Day	35% 6% 9% 25% 23% 2	1980
	11th to 20th	Day	40% 3 9% 26% 19% 3	1819
	21st to end	Day	47% 3 11% 22% 15% 2	1859
November	1st to 10th	Day	34% 3 10% 28% 22% 3	1672
	11th to 20th	Day	47% 4 7% 22% 16% 3	1710
	21st to end	Day	50% 3 9% 23% 15% 1	1710
December	1st to 10th	Day	62% 3 9% 18% 6% 1	1710
	11th to 20th	Day	58% 5% 7% 19% 11%	2150
	21st to end	Day	69% 5% 8% 11% 7% 1	3124
January	1st to 10th	Night	63% 7% 7% 14% 8%	4109
	11th to 20th	Night	65% 4 9% 15% 7%	4120
	21st to end	Night	65% 5% 6% 17% 6% 1	4532
February	1st to 10th	Night	58% 3 10% 20% 8% 1	2376
	11th to 20th	Night	55% 4 9% 20% 12% 1	2219
	21st to end	Night	57% 3 10% 17% 10% 2	1884
March	1st to 10th	Night	54% 4 7% 23% 11% 1	3683
	11th to 20th	Night	39% 6% 10% 27% 15% 1	3480
	21st to end	Night	47% 5% 8% 28% 12% 1	3817
April	1st to 10th	Night	44% 6% 10% 25% 12% 2	1971
	11th to 20th	Night	41% 5% 9% 20% 18% 6%	1815
	21st to end	Night	46% 5% 11% 22% 13% 3	1710
May	1st to 10th	Night	56% 6% 9% 19% 8% 2	2840
	11th to 20th	Night	43% 7% 14% 26% 9% 1	2813
	21st to end	Night	32% 7% 15% 27% 14% 4	3087
June	1st to 10th	Night	32% 6% 12% 27% 20% 3	1710
	11th to 20th	Night	30% 6% 16% 23% 21% 4	1565
	21st to end	Night	29% 9% 17% 23% 17% 5%	1520
July	1st to 10th	Night	34% 6% 11% 24% 19% 6%	2490
	11th to 20th	Night	29% 5% 13% 31% 20% 2	2692
	21st to end	Night	42% 6% 13% 22% 13% 4	2988
August	1st to 10th	Night	33% 7% 14% 32% 12% 1	2814
	11th to 20th	Night	37% 6% 10% 28% 19% 1	2812
	21st to end	Night	20% 5% 16% 33% 23% 3	3426
September	1st to 10th	Night	31% 6% 11% 26% 20% 7%	2009
	11th to 20th	Night	30% 6% 10% 24% 27% 3	2090
	21st to end	Night	37% 4 9% 22% 26% 2	2079
October	1st to 10th	Night	29% 5% 11% 28% 23% 3	1980
	11th to 20th	Night	40% 4 8% 26% 20% 2	2139
	21st to end	Night	46% 3 9% 22% 17% 3	2492
November	1st to 10th	Night	37% 4 9% 22% 23% 4	2406
	11th to 20th	Night	45% 3 8% 21% 19% 3	2470
	21st to end	Night	52% 3 10% 21% 12% 2	2470
December	1st to 10th	Night	57% 4 10% 19% 9% 1	2470
	11th to 20th	Night	56% 4 9% 21% 9% 1	3044
	21st to end	Night	69% 4 8% 14% 5%	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	27% 24% 33% 13% 4	270
	11th to 20th	Day	31% 26% 34% 7% 1	270
	21st to end	Day	33% 23% 31% 11% 2	297
February	1st to 10th	Day	31% 24% 31% 12% 1	270
	11th to 20th	Day	33% 27% 31% 7% 1	270
	21st to end	Day	34% 23% 37% 6%	225
March	1st to 10th	Day	27% 32% 29% 11% 1	293
	11th to 20th	Day	27% 20% 32% 15% 5%	460
	21st to end	Day	34% 17% 29% 14% 5%	506
April	1st to 10th	Day	24% 19% 30% 19% 7% 1	460
	11th to 20th	Day	24% 21% 27% 17% 8% 3	452
	21st to end	Day	24% 19% 32% 14% 8% 2	460
May	1st to 10th	Day	26% 19% 30% 16% 6% 4	463
	11th to 20th	Day	22% 13% 28% 22% 10% 5%	487
	21st to end	Day	14% 8% 27% 28% 14% 8%	529
June	1st to 10th	Day	13% 10% 24% 29% 17% 7%	490
	11th to 20th	Day	11% 7% 25% 31% 20% 6%	629
	21st to end	Day	10% 7% 28% 31% 18% 7%	680
July	1st to 10th	Day	14% 5% 18% 27% 20% 17%	671
	11th to 20th	Day	9% 5% 23% 30% 23% 9%	537
	21st to end	Day	11% 4 19% 31% 24% 11%	532
August	1st to 10th	Day	12% 4 15% 30% 24% 15%	486
	11th to 20th	Day	11% 6% 22% 31% 22% 9%	479
	21st to end	Day	8% 6% 15% 31% 27% 14%	539
September	1st to 10th	Day	12% 6% 18% 29% 26% 10%	490
	11th to 20th	Day	11% 3 17% 27% 30% 12%	490
	21st to end	Day	20% 9% 22% 23% 20% 7%	483
October	1st to 10th	Day	11% 6% 29% 29% 17% 6%	450
	11th to 20th	Day	18% 14% 32% 23% 11% 2	450
	21st to end	Day	26% 12% 39% 18% 5%	374
November	1st to 10th	Day	14% 19% 34% 20% 10% 3	270
	11th to 20th	Day	24% 22% 28% 18% 5% 3	270
	21st to end	Day	25% 20% 37% 15% 3	270
December	1st to 10th	Day	26% 20% 34% 15% 5%	270
	11th to 20th	Day	22% 23% 38% 12% 4	270
	21st to end	Day	31% 21% 36% 10% 2	297
January	1st to 10th	Night	23% 21% 33% 20% 4	760
	11th to 20th	Night	30% 18% 33% 17% 3	760
	21st to end	Night	25% 17% 35% 21% 3	836
February	1st to 10th	Night	29% 12% 34% 23% 2	760
	11th to 20th	Night	25% 20% 33% 21% 1	743
	21st to end	Night	29% 16% 36% 18% 1	628
March	1st to 10th	Night	22% 18% 32% 22% 5%	760
	11th to 20th	Night	25% 15% 33% 21% 6% 1	760
	21st to end	Night	25% 11% 32% 25% 7%	836
April	1st to 10th	Night	21% 13% 34% 25% 7%	641
	11th to 20th	Night	20% 10% 34% 24% 11% 1	563
	21st to end	Night	18% 10% 39% 24% 8% 1	570
May	1st to 10th	Night	21% 10% 30% 26% 11% 1	570
	11th to 20th	Night	18% 5% 25% 33% 17% 2	561
	21st to end	Night	10% 3 24% 35% 24% 5%	617
June	1st to 10th	Night	10% 4 21% 40% 24% 1	570
	11th to 20th	Night	10% 3 16% 43% 25% 3	570
	21st to end	Night	7% 3 24% 39% 24% 3	570
July	1st to 10th	Night	11% 2 13% 32% 33% 8%	555
	11th to 20th	Night	7% 2 18% 34% 36% 4	552
	21st to end	Night	11% 4 12% 38% 33% 3	624
August	1st to 10th	Night	10% 2 11% 38% 36% 3	567
	11th to 20th	Night	10% 3 12% 42% 29% 5%	564
	21st to end	Night	7% 1 13% 36% 37% 6%	627
September	1st to 10th	Night	13% 4 14% 34% 31% 5%	679
	11th to 20th	Night	9% 3 16% 33% 33% 6%	760
	21st to end	Night	16% 7% 22% 33% 21% 3	756
October	1st to 10th	Night	11% 5% 23% 35% 22% 3	720
	11th to 20th	Night	18% 9% 28% 32% 13% 1	720
	21st to end	Night	24% 9% 33% 23% 10%	792
November	1st to 10th	Night	16% 11% 30% 26% 16% 1	740
	11th to 20th	Night	19% 17% 30% 24% 9% 1	760
	21st to end	Night	26% 11% 28% 27% 7% 1	760
December	1st to 10th	Night	27% 14% 32% 23% 5%	760
	11th to 20th	Night	25% 12% 34% 22% 5% 1	760
	21st to end	Night	30% 14% 32% 21% 3	836

Page generated at 2024-09-26 09:52:18. Version ac07

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