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 2024-01-12.

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% 9% 4 7% 6% 3 5% 5% 5% 7% 32%	74586
	Night	16% 10% 4 7% 5% 3 4 4 5% 7% 34%	75128
Transparency	Day	35% 36% 7% 14% 7% 1	74307
	Night	34% 36% 7% 14% 8% 1	74926
Seeing	Day	23% 14% 27% 20% 12% 4	13612
	Night	22% 11% 25% 27% 13% 2	23578

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	19% 14% 7% 10% 8% 4 4 4 3 5% 21%	1706
	11th to 20th	Day	19% 20% 6% 11% 7% 4 3 3 4 5% 19%	1635
	21st to end	Day	17% 20% 6% 12% 7% 3 4 3 4 5% 19%	1782
February	1st to 10th	Day	23% 15% 5% 9% 7% 3 5% 4 4 4 22%	1620
	11th to 20th	Day	17% 14% 8% 13% 5% 4 3 3 5% 7% 23%	1599
	21st to end	Day	21% 13% 6% 8% 6% 3 3 4 3 6% 28%	1480
March	1st to 10th	Day	17% 11% 4 6% 6% 3 4 4 5% 6% 33%	1980
	11th to 20th	Day	19% 11% 5% 7% 8% 3 4 4 6% 5% 29%	1980
	21st to end	Day	23% 9% 4 8% 6% 3 4 4 5% 6% 28%	2178
April	1st to 10th	Day	15% 11% 4 7% 6% 3 4 5% 6% 7% 32%	2039
	11th to 20th	Day	16% 9% 3 6% 7% 4 5% 4 5% 6% 35%	2199
	21st to end	Day	21% 8% 4 7% 5% 4 5% 4 4 7% 32%	2340
May	1st to 10th	Day	19% 8% 3 6% 6% 4 6% 5% 6% 8% 29%	2340
	11th to 20th	Day	21% 8% 3 7% 6% 3 5% 6% 5% 8% 29%	2301
	21st to end	Day	12% 5% 2 6% 6% 4 6% 6% 8% 10% 36%	2544
June	1st to 10th	Day	12% 6% 3 6% 6% 4 5% 6% 6% 10% 37%	2520
	11th to 20th	Day	13% 6% 3 6% 6% 4 6% 5% 7% 9% 35%	2520
	21st to end	Day	14% 5% 3 5% 5% 4 6% 6% 6% 10% 36%	2483
July	1st to 10th	Day	13% 5% 2 6% 6% 3 6% 5% 7% 9% 38%	2340
	11th to 20th	Day	12% 6% 3 5% 6% 4 7% 5% 7% 9% 37%	2340
	21st to end	Day	13% 6% 3 6% 7% 4 6% 6% 6% 9% 33%	2547
August	1st to 10th	Day	12% 6% 2 5% 6% 5% 7% 7% 7% 10% 34%	2327
	11th to 20th	Day	12% 7% 3 6% 6% 4 6% 6% 8% 9% 34%	2303
	21st to end	Day	11% 4 2 5% 6% 4 6% 6% 7% 9% 39%	2480
September	1st to 10th	Day	16% 6% 2 5% 4 3 4 4 5% 7% 45%	2109
	11th to 20th	Day	11% 5% 2 5% 4 3 5% 5% 5% 8% 46%	1980
	21st to end	Day	17% 8% 4 6% 5% 3 4 6% 4 6% 38%	1980
October	1st to 10th	Day	15% 6% 3 7% 5% 3 4 5% 6% 8% 39%	1831
	11th to 20th	Day	18% 7% 2 7% 6% 3 4 4 5% 5% 38%	1800
	21st to end	Day	23% 9% 3 6% 5% 3 4 3 4 7% 34%	1980
November	1st to 10th	Day	11% 8% 3 5% 4 4 5% 4 5% 6% 45%	1754
	11th to 20th	Day	17% 14% 4 5% 4 3 5% 4 5% 6% 33%	1679
	21st to end	Day	19% 14% 5% 7% 5% 4 4 5% 5% 5% 29%	1520
December	1st to 10th	Day	21% 15% 7% 10% 5% 4 5% 3 4 5% 19%	1520
	11th to 20th	Day	20% 16% 7% 10% 6% 3 3 4 4 6% 23%	1910
	21st to end	Day	24% 20% 7% 9% 6% 3 4 4 4 5% 15%	2940
January	1st to 10th	Night	18% 16% 7% 8% 6% 5% 4 5% 5% 4 22%	2459
	11th to 20th	Night	21% 15% 7% 11% 6% 3 4 5% 5% 3 20%	2365
	21st to end	Night	19% 15% 7% 10% 8% 3 4 3 4 5% 24%	2574
February	1st to 10th	Night	21% 13% 5% 9% 5% 3 5% 4 4 4 26%	2340
	11th to 20th	Night	21% 13% 5% 9% 6% 4 5% 4 4 6% 24%	2245
	21st to end	Night	20% 15% 5% 9% 6% 3 4 4 4 5% 25%	1774
March	1st to 10th	Night	16% 11% 5% 6% 6% 3 4 4 4 6% 35%	1980
	11th to 20th	Night	19% 9% 4 6% 5% 3 4 4 4 6% 35%	1980
	21st to end	Night	19% 11% 4 5% 6% 2 4 4 5% 6% 34%	2178
April	1st to 10th	Night	19% 10% 4 6% 6% 2 5% 4 5% 6% 34%	1920
	11th to 20th	Night	16% 9% 2 6% 5% 4 5% 4 6% 8% 36%	1723
	21st to end	Night	17% 8% 3 7% 5% 3 4 4 4 7% 38%	1620
May	1st to 10th	Night	18% 10% 3 6% 5% 4 5% 5% 6% 7% 33%	1620
	11th to 20th	Night	18% 7% 3 6% 5% 4 5% 3 4 9% 36%	1592
	21st to end	Night	9% 5% 3 5% 5% 3 6% 7% 6% 12% 41%	1724
June	1st to 10th	Night	9% 5% 3 5% 5% 4 4 5% 6% 8% 45%	1440
	11th to 20th	Night	11% 6% 2 4 5% 4 6% 5% 7% 12% 39%	1440
	21st to end	Night	11% 4 2 5% 5% 3 5% 5% 6% 8% 45%	1470
July	1st to 10th	Night	10% 5% 3 5% 6% 3 5% 5% 6% 9% 44%	1620
	11th to 20th	Night	9% 4 2 5% 5% 2 5% 5% 5% 9% 49%	1620
	21st to end	Night	11% 6% 2 5% 5% 3 6% 6% 7% 9% 40%	1771
August	1st to 10th	Night	7% 5% 2 6% 5% 4 6% 5% 7% 11% 42%	1611
	11th to 20th	Night	8% 6% 3 6% 6% 3 5% 6% 6% 9% 43%	1598
	21st to end	Night	9% 5% 3 5% 5% 3 4 5% 6% 9% 48%	1858
September	1st to 10th	Night	14% 4 2 4 5% 3 4 4 5% 7% 48%	1847
	11th to 20th	Night	10% 4 2 4 4 3 3 4 4 9% 53%	1980
	21st to end	Night	15% 6% 3 6% 5% 3 5% 5% 4 5% 44%	1980
October	1st to 10th	Night	15% 5% 2 5% 5% 3 4 4 6% 7% 44%	2128
	11th to 20th	Night	17% 7% 3 6% 5% 3 4 4 5% 7% 39%	2160
	21st to end	Night	23% 8% 3 5% 5% 3 3 3 5% 6% 36%	2376
November	1st to 10th	Night	13% 7% 3 5% 4 2 4 3 4 6% 48%	2322
	11th to 20th	Night	17% 10% 4 6% 5% 3 5% 4 5% 6% 34%	2498
	21st to end	Night	19% 12% 4 7% 5% 4 5% 5% 4 5% 31%	2660
December	1st to 10th	Night	22% 15% 5% 9% 6% 3 5% 4 4 5% 22%	2660
	11th to 20th	Night	19% 16% 6% 9% 6% 3 4 4 4 5% 24%	3285
	21st to end	Night	22% 19% 6% 9% 7% 3 4 4 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% 38% 6% 9% 3	1707
	11th to 20th	Day	44% 40% 6% 8% 2	1635
	21st to end	Day	47% 36% 6% 8% 3 1	1782
February	1st to 10th	Day	44% 35% 6% 9% 6% 1	1620
	11th to 20th	Day	43% 36% 7% 9% 4 1	1608
	21st to end	Day	42% 35% 6% 12% 3 2	1480
March	1st to 10th	Day	33% 36% 7% 18% 6%	1980
	11th to 20th	Day	37% 35% 7% 12% 7% 1	1980
	21st to end	Day	39% 35% 6% 11% 7% 1	2178
April	1st to 10th	Day	34% 36% 7% 13% 8% 2	2039
	11th to 20th	Day	35% 35% 7% 10% 12% 2	2199
	21st to end	Day	34% 36% 5% 14% 8% 2	2340
May	1st to 10th	Day	36% 37% 6% 12% 8% 1	2340
	11th to 20th	Day	36% 37% 6% 11% 9% 2	2305
	21st to end	Day	27% 37% 12% 16% 6% 2	2544
June	1st to 10th	Day	26% 36% 11% 17% 8% 1	2520
	11th to 20th	Day	28% 37% 10% 16% 8% 1	2520
	21st to end	Day	29% 37% 9% 15% 10% 1	2483
July	1st to 10th	Day	27% 37% 8% 16% 10% 2	2275
	11th to 20th	Day	29% 37% 9% 14% 10% 1	2271
	21st to end	Day	29% 38% 8% 15% 8% 1	2405
August	1st to 10th	Day	30% 36% 9% 18% 7%	2314
	11th to 20th	Day	29% 36% 8% 18% 9% 1	2303
	21st to end	Day	28% 37% 8% 17% 8% 3	2480
September	1st to 10th	Day	27% 35% 6% 16% 14% 3	2109
	11th to 20th	Day	25% 36% 7% 21% 9% 2	1980
	21st to end	Day	35% 36% 5% 13% 10%	1980
October	1st to 10th	Day	29% 36% 7% 17% 10% 1	1831
	11th to 20th	Day	34% 35% 8% 15% 6%	1800
	21st to end	Day	35% 36% 5% 15% 9% 1	1980
November	1st to 10th	Day	21% 40% 7% 18% 12% 2	1754
	11th to 20th	Day	36% 38% 5% 13% 7% 2	1679
	21st to end	Day	36% 38% 7% 12% 7% 1	1520
December	1st to 10th	Day	43% 38% 7% 10% 2	1520
	11th to 20th	Day	46% 31% 6% 13% 4	1906
	21st to end	Day	58% 24% 8% 8% 1	2940
January	1st to 10th	Night	42% 39% 5% 10% 3	2459
	11th to 20th	Night	43% 40% 7% 7% 3	2365
	21st to end	Night	44% 36% 6% 11% 3	2574
February	1st to 10th	Night	41% 35% 6% 12% 5%	2340
	11th to 20th	Night	43% 36% 6% 10% 5%	2247
	21st to end	Night	43% 35% 5% 11% 4 1	1774
March	1st to 10th	Night	33% 35% 6% 18% 8%	1980
	11th to 20th	Night	34% 35% 7% 15% 7% 1	1980
	21st to end	Night	35% 36% 4 16% 7% 2	2178
April	1st to 10th	Night	33% 35% 7% 12% 11% 2	1920
	11th to 20th	Night	32% 35% 8% 12% 11% 3	1723
	21st to end	Night	31% 36% 6% 15% 9% 2	1620
May	1st to 10th	Night	35% 36% 6% 12% 9% 2	1620
	11th to 20th	Night	32% 37% 6% 11% 13% 3	1593
	21st to end	Night	23% 37% 11% 19% 9% 2	1725
June	1st to 10th	Night	25% 37% 7% 17% 13% 2	1440
	11th to 20th	Night	24% 37% 10% 17% 9% 2	1440
	21st to end	Night	23% 38% 10% 16% 11% 2	1470
July	1st to 10th	Night	24% 38% 9% 16% 12% 2	1575
	11th to 20th	Night	22% 38% 8% 18% 12% 2	1566
	21st to end	Night	26% 39% 8% 17% 8% 2	1672
August	1st to 10th	Night	24% 37% 10% 18% 11%	1600
	11th to 20th	Night	25% 36% 8% 17% 12% 2	1598
	21st to end	Night	24% 37% 7% 17% 11% 4	1858
September	1st to 10th	Night	24% 36% 5% 15% 14% 6%	1847
	11th to 20th	Night	20% 36% 8% 20% 14% 1	1980
	21st to end	Night	30% 36% 6% 15% 11% 1	1980
October	1st to 10th	Night	27% 36% 8% 17% 11% 1	2128
	11th to 20th	Night	31% 36% 7% 17% 8% 1	2160
	21st to end	Night	34% 36% 4 15% 9% 2	2376
November	1st to 10th	Night	22% 39% 5% 18% 14% 2	2322
	11th to 20th	Night	33% 39% 6% 13% 8% 2	2498
	21st to end	Night	35% 39% 5% 14% 6% 1	2660
December	1st to 10th	Night	42% 38% 6% 11% 2	2660
	11th to 20th	Night	44% 31% 8% 13% 3	3288
	21st to end	Night	58% 24% 7% 9% 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	35% 24% 31% 9% 1	245
	21st to end	Day	34% 30% 28% 5% 3	264
February	1st to 10th	Day	45% 18% 30% 7%	240
	11th to 20th	Day	40% 30% 23% 7%	240
	21st to end	Day	39% 26% 31% 4	198
March	1st to 10th	Day	31% 20% 29% 17% 2	420
	11th to 20th	Day	31% 17% 32% 14% 5% 1	420
	21st to end	Day	31% 19% 30% 15% 4	462
April	1st to 10th	Day	28% 17% 30% 17% 7% 1	420
	11th to 20th	Day	24% 22% 27% 16% 8% 3	412
	21st to end	Day	29% 18% 32% 11% 7% 2	420
May	1st to 10th	Day	28% 19% 27% 13% 9% 3	423
	11th to 20th	Day	23% 12% 34% 18% 9% 5%	447
	21st to end	Day	16% 9% 27% 25% 17% 6%	485
June	1st to 10th	Day	16% 9% 25% 32% 15% 3	450
	11th to 20th	Day	17% 11% 23% 29% 13% 6%	450
	21st to end	Day	14% 9% 32% 27% 16% 3	450
July	1st to 10th	Day	16% 7% 18% 27% 21% 12%	445
	11th to 20th	Day	12% 7% 24% 30% 17% 10%	444
	21st to end	Day	16% 6% 23% 28% 18% 10%	488
August	1st to 10th	Day	16% 4 20% 28% 23% 9%	446
	11th to 20th	Day	16% 6% 20% 27% 20% 12%	439
	21st to end	Day	11% 6% 24% 25% 21% 13%	495
September	1st to 10th	Day	18% 5% 21% 26% 21% 8%	450
	11th to 20th	Day	12% 4 18% 30% 25% 11%	450
	21st to end	Day	22% 10% 27% 22% 15% 5%	450
October	1st to 10th	Day	17% 8% 27% 27% 16% 5%	450
	11th to 20th	Day	23% 13% 30% 24% 10% 1	450
	21st to end	Day	30% 15% 29% 19% 6% 1	495
November	1st to 10th	Day	20% 17% 34% 15% 11% 3	352
	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% 16% 29% 19% 3	728
	21st to end	Night	29% 18% 31% 19% 4	792
February	1st to 10th	Night	31% 17% 25% 24% 2	720
	11th to 20th	Night	31% 18% 35% 15% 1	703
	21st to end	Night	30% 17% 34% 17% 2	592
March	1st to 10th	Night	24% 19% 29% 23% 4	720
	11th to 20th	Night	28% 15% 29% 21% 7% 1	720
	21st to end	Night	27% 15% 28% 24% 6% 1	792
April	1st to 10th	Night	27% 14% 30% 22% 7%	720
	11th to 20th	Night	22% 12% 32% 23% 10% 1	659
	21st to end	Night	21% 9% 35% 26% 8%	540
May	1st to 10th	Night	23% 9% 24% 31% 11% 1	540
	11th to 20th	Night	23% 6% 23% 33% 13% 1	531
	21st to end	Night	12% 4 21% 35% 25% 3	564
June	1st to 10th	Night	9% 3 25% 41% 20% 1	360
	11th to 20th	Night	13% 4 21% 39% 21% 1	360
	21st to end	Night	10% 3 25% 38% 23% 1	390
July	1st to 10th	Night	11% 2 16% 38% 27% 6%	525
	11th to 20th	Night	9% 3 16% 36% 32% 3	522
	21st to end	Night	13% 3 13% 36% 31% 3	591
August	1st to 10th	Night	10% 2 12% 40% 32% 4	537
	11th to 20th	Night	11% 4 12% 37% 31% 6%	534
	21st to end	Night	12% 3 16% 32% 30% 7%	670
September	1st to 10th	Night	15% 4 15% 33% 27% 6%	720
	11th to 20th	Night	11% 3 18% 32% 30% 6%	720
	21st to end	Night	17% 7% 23% 28% 20% 4	720
October	1st to 10th	Night	16% 7% 22% 31% 20% 4	720
	11th to 20th	Night	21% 9% 30% 29% 11% 1	720
	21st to end	Night	28% 11% 25% 27% 8% 1	792
November	1st to 10th	Night	18% 10% 27% 30% 14% 1	740
	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 2024-01-09 16:24:25. Version ac07

Copyright 2024 Attilla Danko