Wheeling
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Wheeling 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	16% 10% 3 8% 5% 5% 5% 4 6% 7% 32%	100951
	Night	16% 11% 4 8% 5% 4 4 3 5% 6% 34%	98013
Transparency	Day	27% 46% 6% 13% 7% 1	104614
	Night	28% 46% 5% 13% 7% 1	102489
Seeing	Day	23% 14% 27% 20% 11% 4	14754
	Night	22% 11% 25% 27% 13% 2	24609

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	20% 19% 6% 11% 5% 4 4 2 3 5% 20%	2836
	11th to 20th	Day	14% 22% 9% 13% 8% 4 3 2 4 3 18%	2840
	21st to end	Day	24% 22% 7% 13% 6% 3 3 2 3 4 14%	3124
February	1st to 10th	Day	22% 16% 4 9% 6% 4 4 3 4 4 24%	1710
	11th to 20th	Day	16% 15% 6% 13% 4 4 3 3 5% 6% 24%	1690
	21st to end	Day	21% 14% 5% 9% 5% 3 2 3 4 6% 28%	1571
March	1st to 10th	Day	20% 16% 4 8% 5% 4 4 3 4 6% 28%	3435
	11th to 20th	Day	14% 8% 4 9% 6% 5% 5% 3 6% 5% 35%	3480
	21st to end	Day	21% 8% 3 8% 4 3 5% 4 6% 7% 31%	3815
April	1st to 10th	Day	15% 13% 3 8% 6% 4 4 4 6% 6% 31%	2153
	11th to 20th	Day	16% 10% 3 7% 5% 5% 5% 3 5% 5% 36%	2323
	21st to end	Day	20% 9% 3 8% 4 5% 5% 4 4 7% 32%	2470
May	1st to 10th	Day	22% 9% 4 7% 5% 5% 4 4 6% 7% 28%	4082
	11th to 20th	Day	19% 9% 3 8% 4 4 5% 4 5% 7% 31%	4081
	21st to end	Day	12% 6% 2 7% 5% 5% 6% 4 8% 9% 35%	4502
June	1st to 10th	Day	12% 6% 2 7% 5% 5% 5% 5% 6% 10% 36%	2660
	11th to 20th	Day	12% 6% 3 7% 5% 5% 5% 5% 7% 9% 35%	2660
	21st to end	Day	14% 6% 3 6% 5% 5% 5% 5% 7% 9% 36%	2620
July	1st to 10th	Day	10% 5% 2 7% 5% 5% 5% 4 7% 8% 40%	4120
	11th to 20th	Day	10% 6% 2 5% 5% 5% 6% 3 7% 9% 41%	4120
	21st to end	Day	13% 7% 3 8% 6% 5% 6% 4 6% 8% 34%	4466
August	1st to 10th	Day	12% 7% 3 8% 5% 6% 6% 5% 7% 9% 32%	4104
	11th to 20th	Day	11% 7% 2 7% 5% 6% 6% 5% 8% 8% 36%	4044
	21st to end	Day	7% 3 2 6% 5% 7% 7% 5% 7% 10% 41%	4354
September	1st to 10th	Day	15% 6% 2 5% 4 3 3 3 5% 7% 46%	2226
	11th to 20th	Day	11% 6% 2 6% 4 3 5% 4 5% 9% 46%	2090
	21st to end	Day	18% 9% 3 7% 4 4 4 4 4 6% 36%	2090
October	1st to 10th	Day	14% 6% 3 7% 4 4 4 4 6% 7% 41%	1932
	11th to 20th	Day	17% 8% 2 7% 5% 4 4 4 5% 5% 39%	1900
	21st to end	Day	21% 10% 2 7% 3 4 4 2 4 7% 35%	2090
November	1st to 10th	Day	10% 9% 3 6% 4 5% 4 4 6% 6% 45%	1794
	11th to 20th	Day	16% 16% 4 5% 4 3 5% 3 5% 6% 33%	1679
	21st to end	Day	18% 15% 4 8% 4 4 4 4 5% 5% 29%	1520
December	1st to 10th	Day	21% 17% 6% 11% 4 6% 4 3 5% 5% 19%	1520
	11th to 20th	Day	19% 17% 6% 12% 5% 4 3 3 4 5% 23%	1910
	21st to end	Day	24% 21% 6% 10% 5% 4 3 3 4 5% 15%	2940
January	1st to 10th	Night	16% 20% 8% 12% 5% 4 3 3 4 5% 20%	4109
	11th to 20th	Night	17% 18% 7% 15% 5% 5% 5% 3 4 3 17%	4120
	21st to end	Night	27% 18% 6% 13% 5% 3 3 1 3 3 18%	4532
February	1st to 10th	Night	20% 15% 4 10% 5% 4 4 3 4 4 27%	2470
	11th to 20th	Night	20% 14% 4 10% 5% 5% 4 4 5% 5% 25%	2374
	21st to end	Night	20% 16% 4 10% 5% 4 4 3 4 5% 25%	1881
March	1st to 10th	Night	21% 12% 4 7% 4 4 4 3 4 6% 32%	3418
	11th to 20th	Night	15% 10% 5% 8% 5% 4 4 3 5% 6% 35%	3480
	21st to end	Night	17% 10% 3 6% 5% 3 4 3 5% 6% 39%	3817
April	1st to 10th	Night	19% 12% 3 7% 5% 4 4 3 5% 6% 33%	2026
	11th to 20th	Night	16% 10% 2 6% 5% 5% 5% 3 6% 8% 36%	1820
	21st to end	Night	16% 9% 3 7% 4 3 5% 3 4 7% 39%	1710
May	1st to 10th	Night	27% 12% 3 7% 4 4 4 3 5% 6% 27%	2813
	11th to 20th	Night	17% 10% 2 7% 4 4 3 3 4 7% 37%	2812
	21st to end	Night	11% 7% 3 6% 5% 4 5% 5% 6% 10% 38%	3032
June	1st to 10th	Night	9% 6% 2 6% 5% 4 5% 4 7% 8% 44%	1520
	11th to 20th	Night	10% 6% 2 6% 4 5% 5% 4 8% 12% 39%	1520
	21st to end	Night	11% 5% 1 6% 5% 4 5% 5% 6% 9% 44%	1552
July	1st to 10th	Night	11% 6% 3 7% 5% 4 4 4 6% 9% 42%	2840
	11th to 20th	Night	10% 5% 2 7% 4 4 5% 3 6% 8% 45%	2840
	21st to end	Night	9% 8% 3 7% 5% 4 5% 5% 6% 8% 41%	3087
August	1st to 10th	Night	10% 9% 3 8% 5% 6% 5% 4 7% 10% 34%	2825
	11th to 20th	Night	11% 7% 3 7% 4 4 5% 4 6% 7% 41%	2785
	21st to end	Night	6% 4 2 6% 5% 5% 5% 4 7% 9% 46%	3270
September	1st to 10th	Night	14% 4 2 5% 4 4 4 3 5% 6% 50%	1950
	11th to 20th	Night	10% 5% 2 4 3 4 3 3 5% 8% 54%	2090
	21st to end	Night	16% 7% 2 6% 5% 4 5% 3 4 5% 43%	2090
October	1st to 10th	Night	14% 5% 2 6% 4 4 4 3 6% 6% 45%	2247
	11th to 20th	Night	16% 7% 3 7% 4 4 4 3 5% 7% 40%	2280
	21st to end	Night	22% 8% 3 6% 4 3 3 3 5% 6% 38%	2508
November	1st to 10th	Night	13% 8% 2 5% 4 3 4 3 4 7% 47%	2382
	11th to 20th	Night	17% 12% 3 7% 4 4 5% 3 5% 6% 34%	2498
	21st to end	Night	18% 13% 4 7% 4 5% 4 4 5% 5% 30%	2660
December	1st to 10th	Night	21% 16% 5% 9% 5% 5% 4 3 4 5% 22%	2660
	11th to 20th	Night	19% 17% 6% 10% 5% 4 3 3 4 5% 24%	3285
	21st to end	Night	22% 20% 5% 11% 5% 4 4 3 4 5% 17%	4710

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	44% 37% 7% 9% 3	2837
	11th to 20th	Day	48% 36% 4 8% 4 1	2840
	21st to end	Day	51% 39% 2 7% 2	3124
February	1st to 10th	Day	24% 65% 3 5% 3	1710
	11th to 20th	Day	21% 64% 3 8% 4	1699
	21st to end	Day	19% 64% 4 7% 5% 1	1571
March	1st to 10th	Day	41% 40% 4 12% 3	3435
	11th to 20th	Day	30% 40% 5% 20% 5%	3480
	21st to end	Day	31% 40% 5% 15% 9% 1	3815
April	1st to 10th	Day	21% 65% 3 8% 3 1	2153
	11th to 20th	Day	17% 66% 4 8% 5% 1	2323
	21st to end	Day	19% 65% 4 8% 4	2470
May	1st to 10th	Day	36% 40% 5% 15% 4	4120
	11th to 20th	Day	32% 40% 6% 17% 5%	4085
	21st to end	Day	27% 41% 8% 14% 8% 2	4516
June	1st to 10th	Day	17% 66% 4 8% 5%	2660
	11th to 20th	Day	16% 66% 4 9% 4	2660
	21st to end	Day	16% 64% 5% 9% 5%	2620
July	1st to 10th	Day	27% 38% 8% 15% 11% 2	4055
	11th to 20th	Day	24% 37% 7% 21% 11%	4051
	21st to end	Day	31% 36% 7% 12% 13% 2	4324
August	1st to 10th	Day	30% 39% 9% 15% 6%	4091
	11th to 20th	Day	26% 39% 6% 20% 9%	4083
	21st to end	Day	22% 39% 9% 19% 10%	4354
September	1st to 10th	Day	14% 60% 5% 9% 9% 1	2226
	11th to 20th	Day	13% 61% 6% 11% 8% 1	2090
	21st to end	Day	20% 60% 4 10% 6%	2090
October	1st to 10th	Day	16% 37% 5% 25% 16% 2	3205
	11th to 20th	Day	26% 37% 7% 13% 12% 4	3140
	21st to end	Day	19% 37% 9% 19% 15% 1	3428
November	1st to 10th	Day	20% 58% 5% 11% 5% 1	1794
	11th to 20th	Day	19% 61% 3 11% 6% 1	1679
	21st to end	Day	24% 60% 5% 8% 2	1520
December	1st to 10th	Day	29% 60% 4 5% 2	1520
	11th to 20th	Day	34% 48% 4 12% 2	1906
	21st to end	Day	49% 37% 6% 6% 2	2940
January	1st to 10th	Night	46% 36% 6% 9% 3	4109
	11th to 20th	Night	49% 37% 6% 7% 2	4120
	21st to end	Night	49% 38% 2 8% 2	4532
February	1st to 10th	Night	22% 65% 3 7% 3	2470
	11th to 20th	Night	21% 64% 2 9% 3	2376
	21st to end	Night	22% 65% 3 5% 4	1881
March	1st to 10th	Night	36% 40% 5% 14% 5%	3418
	11th to 20th	Night	31% 40% 6% 20% 4	3480
	21st to end	Night	27% 41% 5% 19% 8% 1	3817
April	1st to 10th	Night	21% 66% 2 8% 3	2026
	11th to 20th	Night	16% 66% 4 7% 5% 1	1820
	21st to end	Night	16% 65% 4 8% 7%	1710
May	1st to 10th	Night	40% 40% 4 11% 4 1	2840
	11th to 20th	Night	31% 41% 5% 19% 4	2813
	21st to end	Night	26% 41% 8% 14% 7% 3	3039
June	1st to 10th	Night	14% 66% 4 10% 6%	1520
	11th to 20th	Night	14% 66% 5% 7% 7% 1	1520
	21st to end	Night	15% 64% 5% 10% 6%	1552
July	1st to 10th	Night	28% 37% 5% 15% 11% 3	2795
	11th to 20th	Night	25% 37% 8% 20% 9%	2786
	21st to end	Night	27% 37% 6% 13% 15% 2	2988
August	1st to 10th	Night	32% 39% 9% 15% 4	2814
	11th to 20th	Night	29% 38% 5% 16% 12%	2812
	21st to end	Night	21% 38% 9% 23% 9%	3270
September	1st to 10th	Night	14% 60% 6% 10% 9% 2	1950
	11th to 20th	Night	12% 60% 6% 10% 12% 1	2090
	21st to end	Night	18% 59% 4 9% 8% 1	2090
October	1st to 10th	Night	20% 36% 4 20% 18% 2	3754
	11th to 20th	Night	21% 38% 6% 15% 12% 8%	3779
	21st to end	Night	17% 36% 5% 20% 19% 2	4120
November	1st to 10th	Night	20% 57% 6% 9% 6% 1	2382
	11th to 20th	Night	20% 59% 3 10% 8% 1	2498
	21st to end	Night	24% 59% 6% 8% 2	2660
December	1st to 10th	Night	27% 59% 4 6% 3	2660
	11th to 20th	Night	33% 49% 6% 11% 2	3288
	21st to end	Night	48% 37% 4 8% 2	4710

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	34% 24% 27% 9% 4 1	270
	11th to 20th	Day	39% 24% 28% 9% 1	270
	21st to end	Day	34% 29% 29% 6% 3	297
February	1st to 10th	Day	40% 19% 31% 10%	270
	11th to 20th	Day	39% 29% 25% 7% 1	270
	21st to end	Day	39% 26% 30% 5%	226
March	1st to 10th	Day	33% 19% 28% 17% 3	460
	11th to 20th	Day	32% 18% 31% 14% 4 1	460
	21st to end	Day	31% 20% 30% 15% 4	506
April	1st to 10th	Day	30% 16% 30% 17% 6% 1	460
	11th to 20th	Day	23% 23% 28% 15% 8% 3	452
	21st to end	Day	28% 18% 33% 13% 7% 2	460
May	1st to 10th	Day	28% 19% 27% 14% 10% 2	463
	11th to 20th	Day	22% 13% 32% 18% 9% 5%	487
	21st to end	Day	16% 10% 27% 26% 16% 5%	529
June	1st to 10th	Day	16% 10% 25% 31% 15% 3	490
	11th to 20th	Day	16% 11% 24% 30% 14% 6%	490
	21st to end	Day	14% 10% 32% 26% 15% 3	490
July	1st to 10th	Day	16% 7% 19% 27% 20% 11%	485
	11th to 20th	Day	12% 7% 25% 29% 17% 10%	484
	21st to end	Day	15% 7% 23% 28% 18% 9%	532
August	1st to 10th	Day	16% 5% 21% 28% 22% 8%	486
	11th to 20th	Day	16% 6% 22% 27% 18% 11%	479
	21st to end	Day	10% 6% 23% 26% 22% 13%	539
September	1st to 10th	Day	18% 5% 23% 27% 20% 8%	490
	11th to 20th	Day	12% 3 19% 30% 25% 11%	490
	21st to end	Day	25% 10% 26% 21% 14% 4	490
October	1st to 10th	Day	16% 8% 28% 26% 17% 5%	490
	11th to 20th	Day	23% 13% 28% 23% 10% 2	490
	21st to end	Day	28% 15% 30% 19% 6% 1	539
November	1st to 10th	Day	19% 17% 34% 16% 11% 2	368
	11th to 20th	Day	32% 16% 29% 16% 7%	255
	21st to end	Day	26% 24% 37% 12% 1 1	180
December	1st to 10th	Day	35% 22% 29% 9% 3 1	180
	11th to 20th	Day	29% 27% 29% 12% 3	180
	21st to end	Day	36% 26% 24% 11% 3	247
January	1st to 10th	Night	30% 18% 32% 17% 3 1	760
	11th to 20th	Night	32% 18% 29% 18% 3	760
	21st to end	Night	30% 17% 30% 19% 4	836
February	1st to 10th	Night	30% 17% 25% 25% 3	760
	11th to 20th	Night	31% 18% 35% 15% 1	743
	21st to end	Night	30% 17% 33% 18% 2	628
March	1st to 10th	Night	25% 18% 29% 24% 4	760
	11th to 20th	Night	27% 17% 28% 21% 6% 1	760
	21st to end	Night	27% 15% 29% 24% 5%	836
April	1st to 10th	Night	27% 14% 31% 21% 6%	760
	11th to 20th	Night	22% 12% 31% 23% 10% 1	696
	21st to end	Night	21% 9% 35% 27% 8%	570
May	1st to 10th	Night	24% 9% 24% 31% 11% 1	570
	11th to 20th	Night	23% 6% 23% 33% 14% 1	561
	21st to end	Night	12% 4 21% 36% 25% 3	595
June	1st to 10th	Night	10% 3 26% 40% 20% 1	380
	11th to 20th	Night	13% 4 19% 41% 22% 1	380
	21st to end	Night	10% 3 26% 37% 23%	412
July	1st to 10th	Night	11% 3 16% 39% 26% 6%	555
	11th to 20th	Night	9% 3 16% 37% 31% 3	552
	21st to end	Night	13% 3 13% 38% 30% 3	624
August	1st to 10th	Night	10% 3 14% 39% 31% 3	567
	11th to 20th	Night	11% 4 12% 38% 29% 6%	564
	21st to end	Night	11% 3 16% 32% 31% 6%	708
September	1st to 10th	Night	15% 4 16% 34% 25% 6%	760
	11th to 20th	Night	11% 3 18% 32% 30% 6%	760
	21st to end	Night	19% 7% 22% 28% 19% 4	760
October	1st to 10th	Night	16% 7% 22% 32% 20% 4	760
	11th to 20th	Night	20% 8% 29% 29% 12% 1	760
	21st to end	Night	26% 11% 26% 27% 9% 1	836
November	1st to 10th	Night	18% 9% 28% 30% 14% 1	760
	11th to 20th	Night	26% 16% 26% 23% 8% 1	760
	21st to end	Night	27% 12% 29% 25% 6%	760
December	1st to 10th	Night	32% 16% 27% 20% 5%	760
	11th to 20th	Night	30% 17% 29% 20% 4	760
	21st to end	Night	31% 15% 29% 22% 2	836

Page generated at 2024-11-03 02:11:21. Version ac07

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