Chillicothe
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Chillicothe clear sky chart from 2005-11-06 to 2024-11-05.

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% 8% 3 7% 4 4 4 4 5% 7% 43%	101255
	Night	12% 7% 3 6% 4 4 4 3 5% 6% 45%	97861
Transparency	Day	39% 5% 12% 25% 16% 2	104899
	Night	38% 4 12% 25% 18% 3	102357
Seeing	Day	15% 10% 27% 28% 16% 4	15726
	Night	15% 9% 31% 32% 12% 1	25548

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	14% 11% 4 12% 4 4 3 3 5% 6% 32%	2699
	11th to 20th	Day	11% 12% 4 9% 5% 6% 8% 3 4 5% 34%	2850
	21st to end	Day	16% 15% 7% 13% 5% 5% 4 3 4 4 24%	3135
February	1st to 10th	Day	14% 12% 3 8% 5% 4 4 4 6% 7% 33%	1710
	11th to 20th	Day	14% 10% 4 7% 4 3 3 3 6% 6% 40%	1664
	21st to end	Day	13% 11% 3 7% 4 4 4 4 5% 6% 41%	1576
March	1st to 10th	Day	16% 10% 3 6% 3 3 3 3 4 5% 44%	3436
	11th to 20th	Day	10% 8% 3 6% 4 3 4 3 5% 7% 47%	3480
	21st to end	Day	19% 15% 4 8% 5% 4 4 3 5% 6% 28%	3814
April	1st to 10th	Day	16% 8% 4 7% 4 4 4 3 4 6% 41%	2256
	11th to 20th	Day	15% 8% 2 7% 4 4 3 3 4 7% 41%	2254
	21st to end	Day	22% 8% 3 6% 4 4 4 4 4 7% 34%	2351
May	1st to 10th	Day	15% 8% 3 6% 4 4 4 4 6% 7% 37%	4082
	11th to 20th	Day	17% 8% 3 7% 5% 4 4 4 5% 7% 38%	4163
	21st to end	Day	12% 6% 2 6% 4 4 3 3 5% 7% 46%	4824
June	1st to 10th	Day	6% 5% 2 5% 5% 4 5% 4 8% 10% 46%	2660
	11th to 20th	Day	7% 5% 2 6% 5% 4 5% 4 7% 10% 46%	2660
	21st to end	Day	9% 4 2 6% 5% 4 4 5% 6% 9% 47%	2660
July	1st to 10th	Day	10% 8% 3 7% 5% 5% 5% 4 6% 8% 39%	4440
	11th to 20th	Day	7% 4 2 5% 4 3 4 4 6% 9% 53%	4162
	21st to end	Day	5% 4 2 5% 5% 5% 6% 5% 8% 10% 45%	4465
August	1st to 10th	Day	5% 3 2 4 4 4 5% 5% 7% 10% 51%	4104
	11th to 20th	Day	11% 5% 2 6% 4 5% 4 4 6% 8% 45%	4041
	21st to end	Day	5% 5% 2 5% 4 4 4 4 6% 9% 53%	4190
September	1st to 10th	Day	12% 4 1 5% 3 3 3 3 5% 7% 54%	2280
	11th to 20th	Day	10% 4 2 5% 3 4 4 4 6% 8% 50%	2209
	21st to end	Day	9% 5% 2 4 4 4 4 4 4 6% 55%	2021
October	1st to 10th	Day	13% 5% 3 5% 4 3 3 3 4 6% 52%	1900
	11th to 20th	Day	13% 6% 2 5% 4 3 3 3 4 4 54%	1900
	21st to end	Day	15% 7% 2 6% 3 4 3 3 5% 6% 46%	2090
November	1st to 10th	Day	11% 7% 2 4 3 3 3 3 5% 6% 53%	1871
	11th to 20th	Day	14% 6% 3 6% 4 3 4 4 5% 6% 47%	1567
	21st to end	Day	17% 12% 3 5% 3 3 3 3 4 5% 43%	1520
December	1st to 10th	Day	10% 9% 4 9% 6% 4 5% 3 4 6% 40%	1520
	11th to 20th	Day	13% 10% 4 8% 4 4 4 3 5% 6% 39%	1918
	21st to end	Day	19% 14% 8% 12% 4 4 4 3 4 5% 23%	2783
January	1st to 10th	Night	10% 9% 5% 14% 6% 5% 4 4 4 5% 34%	4240
	11th to 20th	Night	12% 11% 5% 8% 5% 6% 6% 4 6% 5% 32%	4120
	21st to end	Night	16% 13% 6% 11% 5% 4 4 2 4 5% 29%	4532
February	1st to 10th	Night	13% 11% 4 7% 6% 4 4 3 5% 5% 38%	2470
	11th to 20th	Night	12% 8% 4 7% 4 4 4 3 6% 6% 42%	2403
	21st to end	Night	14% 8% 3 6% 3 3 3 3 4 6% 46%	1893
March	1st to 10th	Night	15% 9% 2 5% 4 3 3 2 4 5% 46%	3419
	11th to 20th	Night	12% 7% 2 5% 3 3 3 2 4 6% 53%	3480
	21st to end	Night	18% 9% 5% 9% 6% 5% 4 3 6% 6% 29%	3817
April	1st to 10th	Night	11% 7% 2 6% 4 3 5% 3 4 7% 48%	1924
	11th to 20th	Night	14% 9% 3 6% 4 4 4 3 4 6% 44%	1875
	21st to end	Night	15% 9% 3 6% 4 4 4 3 5% 6% 41%	1824
May	1st to 10th	Night	15% 7% 2 6% 4 4 5% 4 6% 8% 39%	2823
	11th to 20th	Night	14% 7% 3 6% 5% 4 3 4 5% 8% 42%	2738
	21st to end	Night	11% 5% 2 5% 4 3 4 3 4 6% 52%	2743
June	1st to 10th	Night	5% 3 2 4 3 4 5% 4 7% 10% 53%	1520
	11th to 20th	Night	5% 4 1 5% 4 4 4 5% 6% 11% 49%	1520
	21st to end	Night	6% 4 1 3 4 3 4 4 6% 9% 55%	1520
July	1st to 10th	Night	11% 6% 2 6% 4 4 4 4 5% 8% 46%	2530
	11th to 20th	Night	3 2 1 4 3 4 4 4 5% 9% 62%	2804
	21st to end	Night	5% 5% 2 5% 4 4 5% 4 7% 11% 48%	3098
August	1st to 10th	Night	2 2 1 4 3 4 4 4 7% 10% 58%	2836
	11th to 20th	Night	12% 5% 2 5% 3 3 3 2 4 7% 53%	2798
	21st to end	Night	4 3 2 6% 3 4 4 3 6% 8% 57%	3464
September	1st to 10th	Night	10% 4 2 4 3 3 3 3 4 6% 58%	1900
	11th to 20th	Night	10% 4 1 4 4 3 4 4 6% 6% 55%	1966
	21st to end	Night	7% 5% 2 5% 4 4 4 3 5% 5% 58%	2138
October	1st to 10th	Night	10% 6% 2 4 3 3 3 2 5% 6% 57%	2280
	11th to 20th	Night	14% 4 2 5% 4 4 2 2 4 5% 55%	2280
	21st to end	Night	17% 7% 2 5% 3 3 3 2 4 5% 50%	2508
November	1st to 10th	Night	10% 5% 1 4 3 2 3 3 4 6% 59%	2304
	11th to 20th	Night	12% 7% 2 5% 4 3 4 2 3 6% 51%	2611
	21st to end	Night	17% 8% 3 4 4 3 3 3 4 5% 46%	2660
December	1st to 10th	Night	13% 8% 3 7% 4 5% 4 4 5% 6% 43%	2660
	11th to 20th	Night	13% 9% 3 6% 4 4 4 3 5% 6% 44%	3279
	21st to end	Night	21% 16% 6% 10% 5% 4 3 2 3 4 26%	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	52% 3 14% 22% 8% 1	2700
	11th to 20th	Day	55% 3 14% 19% 9%	2850
	21st to end	Day	63% 3 11% 15% 7% 1	3135
February	1st to 10th	Day	50% 4 14% 19% 10% 2	1710
	11th to 20th	Day	45% 4 12% 23% 15% 2	1673
	21st to end	Day	43% 4 12% 22% 16% 2	1576
March	1st to 10th	Day	43% 4 10% 24% 19% 1	3436
	11th to 20th	Day	36% 4 12% 27% 18% 3	3480
	21st to end	Day	57% 5% 15% 18% 4 1	3814
April	1st to 10th	Day	43% 4 12% 25% 13% 2	2256
	11th to 20th	Day	44% 5% 11% 25% 14% 1	2254
	21st to end	Day	50% 5% 11% 22% 12% 1	2351
May	1st to 10th	Day	45% 6% 12% 23% 14% 1	4120
	11th to 20th	Day	47% 5% 12% 26% 10%	4167
	21st to end	Day	38% 5% 11% 28% 17% 1	4837
June	1st to 10th	Day	31% 8% 16% 30% 13% 2	2660
	11th to 20th	Day	32% 7% 14% 27% 18% 2	2660
	21st to end	Day	32% 7% 17% 28% 14% 3	2660
July	1st to 10th	Day	42% 6% 12% 25% 12% 3	4371
	11th to 20th	Day	29% 6% 11% 33% 19% 2	4091
	21st to end	Day	29% 8% 17% 31% 14% 1	4325
August	1st to 10th	Day	27% 5% 17% 32% 18% 1	4090
	11th to 20th	Day	37% 5% 13% 27% 16% 1	4080
	21st to end	Day	28% 6% 17% 30% 13% 6%	4189
September	1st to 10th	Day	32% 4 12% 26% 21% 6%	2280
	11th to 20th	Day	31% 6% 10% 30% 20% 3	2209
	21st to end	Day	31% 4 9% 31% 21% 3	2021
October	1st to 10th	Day	20% 2 7% 21% 44% 6%	3160
	11th to 20th	Day	24% 2 5% 22% 39% 9%	3140
	21st to end	Day	35% 4 9% 25% 25% 2	3428
November	1st to 10th	Day	33% 3 14% 27% 19% 4	1871
	11th to 20th	Day	38% 3 11% 27% 19% 2	1567
	21st to end	Day	45% 2 10% 27% 15%	1520
December	1st to 10th	Day	45% 4 14% 24% 13% 1	1520
	11th to 20th	Day	46% 4 15% 28% 6% 1	1915
	21st to end	Day	64% 4 10% 15% 7% 1	2783
January	1st to 10th	Night	52% 4 11% 22% 10% 1	4240
	11th to 20th	Night	52% 3 12% 20% 12% 1	4120
	21st to end	Night	58% 3 13% 17% 8% 1	4532
February	1st to 10th	Night	49% 4 12% 19% 13% 3	2470
	11th to 20th	Night	42% 5% 11% 24% 15% 2	2404
	21st to end	Night	41% 3 10% 23% 19% 4	1893
March	1st to 10th	Night	41% 3 10% 24% 19% 3	3419
	11th to 20th	Night	34% 3 9% 29% 20% 5%	3480
	21st to end	Night	55% 4 15% 20% 5% 1	3817
April	1st to 10th	Night	37% 4 10% 28% 18% 4	1924
	11th to 20th	Night	41% 4 9% 27% 16% 3	1875
	21st to end	Night	45% 3 10% 24% 16% 1	1824
May	1st to 10th	Night	42% 7% 13% 23% 15% 1	2850
	11th to 20th	Night	40% 6% 12% 29% 12% 1	2739
	21st to end	Night	34% 5% 11% 25% 23% 2	2751
June	1st to 10th	Night	25% 6% 19% 31% 16% 3	1520
	11th to 20th	Night	28% 6% 12% 30% 19% 5%	1520
	21st to end	Night	24% 6% 15% 30% 20% 4	1520
July	1st to 10th	Night	36% 4 12% 25% 19% 4	2490
	11th to 20th	Night	20% 5% 16% 36% 21% 3	2752
	21st to end	Night	28% 6% 20% 31% 14% 1	2999
August	1st to 10th	Night	19% 6% 18% 32% 23% 1	2826
	11th to 20th	Night	33% 4 12% 28% 23% 1	2825
	21st to end	Night	25% 5% 16% 33% 17% 5%	3464
September	1st to 10th	Night	28% 5% 10% 26% 24% 8%	1900
	11th to 20th	Night	28% 4 12% 29% 24% 4	1966
	21st to end	Night	29% 4 8% 30% 26% 4	2138
October	1st to 10th	Night	18% 2 7% 18% 50% 5%	3800
	11th to 20th	Night	23% 2 6% 22% 35% 11%	3779
	21st to end	Night	36% 2 8% 27% 25% 3	4120
November	1st to 10th	Night	28% 4 14% 26% 22% 6%	2304
	11th to 20th	Night	36% 2 8% 30% 19% 4	2611
	21st to end	Night	41% 3 10% 27% 17% 2	2660
December	1st to 10th	Night	42% 4 13% 27% 13% 1	2660
	11th to 20th	Night	41% 4 13% 30% 11% 1	3281
	21st to end	Night	64% 3 8% 16% 7% 1	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% 15% 31% 24% 5%	270
	11th to 20th	Day	26% 17% 38% 18% 1	270
	21st to end	Day	15% 17% 45% 19% 3	297
February	1st to 10th	Day	24% 19% 39% 15% 3	270
	11th to 20th	Day	20% 20% 38% 14% 7%	270
	21st to end	Day	20% 20% 40% 15% 4	225
March	1st to 10th	Day	17% 17% 44% 19% 2	270
	11th to 20th	Day	26% 14% 33% 22% 4	270
	21st to end	Day	38% 17% 27% 14% 4	297
April	1st to 10th	Day	21% 16% 36% 20% 6%	436
	11th to 20th	Day	20% 15% 34% 23% 6% 2	452
	21st to end	Day	23% 18% 31% 21% 7%	531
May	1st to 10th	Day	20% 12% 35% 23% 9% 1	653
	11th to 20th	Day	19% 10% 28% 28% 11% 3	675
	21st to end	Day	16% 8% 28% 27% 18% 3	734
June	1st to 10th	Day	6% 4 20% 36% 24% 9%	680
	11th to 20th	Day	8% 5% 25% 37% 21% 5%	680
	21st to end	Day	9% 5% 34% 33% 16% 3	680
July	1st to 10th	Day	10% 3 14% 30% 30% 13%	671
	11th to 20th	Day	7% 3 19% 36% 25% 10%	668
	21st to end	Day	7% 2 15% 36% 32% 8%	739
August	1st to 10th	Day	8% 2 16% 40% 27% 7%	676
	11th to 20th	Day	11% 4 15% 35% 29% 6%	665
	21st to end	Day	9% 2 14% 32% 32% 11%	549
September	1st to 10th	Day	13% 4 15% 32% 28% 8%	490
	11th to 20th	Day	9% 4 18% 34% 27% 8%	419
	21st to end	Day	12% 8% 24% 32% 17% 7%	300
October	1st to 10th	Day	16% 6% 30% 27% 14% 7%	300
	11th to 20th	Day	14% 22% 35% 19% 10% 1	300
	21st to end	Day	21% 18% 31% 23% 7% 1	330
November	1st to 10th	Day	16% 8% 39% 26% 7% 4	282
	11th to 20th	Day	18% 18% 32% 24% 5% 3	270
	21st to end	Day	23% 15% 29% 27% 5% 1	270
December	1st to 10th	Day	10% 17% 37% 24% 9% 3	270
	11th to 20th	Day	19% 16% 36% 23% 6% 1	270
	21st to end	Day	22% 23% 36% 19% 1	297
January	1st to 10th	Night	13% 13% 40% 26% 7%	950
	11th to 20th	Night	17% 14% 39% 23% 6% 1	950
	21st to end	Night	16% 12% 38% 29% 4	1045
February	1st to 10th	Night	18% 13% 40% 25% 5%	950
	11th to 20th	Night	17% 13% 38% 27% 4	929
	21st to end	Night	20% 15% 42% 19% 4 1	637
March	1st to 10th	Night	17% 13% 40% 25% 5%	570
	11th to 20th	Night	22% 11% 35% 27% 5% 1	570
	21st to end	Night	28% 9% 36% 23% 4	627
April	1st to 10th	Night	15% 11% 43% 27% 4	570
	11th to 20th	Night	20% 12% 33% 27% 7%	563
	21st to end	Night	20% 11% 34% 28% 6% 1	570
May	1st to 10th	Night	15% 9% 34% 32% 8% 1	570
	11th to 20th	Night	18% 7% 26% 35% 13% 1	561
	21st to end	Night	13% 6% 25% 36% 18% 2	617
June	1st to 10th	Night	7% 3 21% 43% 22% 3	570
	11th to 20th	Night	7% 3 26% 46% 16% 2	570
	21st to end	Night	6% 2 28% 47% 17%	570
July	1st to 10th	Night	8% 3 12% 38% 35% 4	555
	11th to 20th	Night	5% 2 14% 47% 29% 2	552
	21st to end	Night	8% 2 14% 42% 33% 2	624
August	1st to 10th	Night	4 2 16% 49% 28% 1	567
	11th to 20th	Night	8% 2 13% 43% 31% 3	564
	21st to end	Night	6% 1 12% 42% 34% 4	627
September	1st to 10th	Night	11% 2 17% 39% 27% 4	570
	11th to 20th	Night	11% 3 18% 39% 25% 4	570
	21st to end	Night	8% 5% 26% 39% 20% 3	618
October	1st to 10th	Night	11% 5% 31% 32% 19% 2	760
	11th to 20th	Night	15% 9% 36% 30% 10% 1	760
	21st to end	Night	20% 11% 32% 27% 8%	836
November	1st to 10th	Night	11% 10% 34% 36% 10%	760
	11th to 20th	Night	15% 12% 39% 26% 8%	901
	21st to end	Night	21% 10% 35% 27% 6%	950
December	1st to 10th	Night	17% 11% 38% 27% 6% 1	950
	11th to 20th	Night	20% 8% 36% 29% 6%	950
	21st to end	Night	23% 15% 34% 24% 3	1045

Page generated at 2024-11-03 01:11:26. Version ac07

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