Dodgeville
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Dodgeville clear sky chart from 2005-11-06 to 2026-03-18.

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 8% 5% 4 5% 4 6% 7% 38%	131519
	Night	12% 10% 4 8% 5% 4 4 3 5% 6% 38%	130298
Transparency	Day	45% 4 12% 26% 13% 1	135003
	Night	46% 3 11% 24% 15% 2	134888
Seeing	Day	17% 12% 30% 25% 13% 4	17696
	Night	17% 11% 31% 30% 11% 1	27718

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	8% 12% 7% 17% 7% 6% 5% 3 5% 5% 25%	4691
	11th to 20th	Day	6% 9% 7% 12% 6% 5% 5% 7% 7% 7% 30%	4710
	21st to end	Day	9% 12% 6% 9% 5% 4 4 3 4 6% 38%	5553
February	1st to 10th	Day	10% 13% 6% 10% 5% 4 5% 4 5% 7% 31%	1890
	11th to 20th	Day	12% 11% 4 7% 5% 4 5% 4 5% 6% 36%	1939
	21st to end	Day	12% 13% 4 8% 6% 5% 5% 3 4 6% 33%	1730
March	1st to 10th	Day	14% 9% 3 6% 4 3 3 3 4 6% 46%	4580
	11th to 20th	Day	11% 6% 2 7% 4 3 4 3 5% 8% 44%	5001
	21st to end	Day	21% 13% 4 10% 4 4 4 3 4 5% 29%	5823
April	1st to 10th	Day	18% 12% 4 7% 5% 5% 4 4 5% 6% 30%	2400
	11th to 20th	Day	16% 11% 3 9% 5% 4 4 4 5% 5% 34%	2374
	21st to end	Day	19% 9% 3 8% 5% 5% 4 3 6% 6% 32%	2423
May	1st to 10th	Day	14% 8% 2 7% 4 4 4 4 5% 7% 40%	6178
	11th to 20th	Day	13% 6% 2 7% 5% 4 5% 4 6% 8% 41%	6319
	21st to end	Day	15% 6% 2 6% 4 4 5% 4 6% 9% 38%	6935
June	1st to 10th	Day	11% 5% 2 5% 5% 4 4 4 6% 9% 45%	2800
	11th to 20th	Day	12% 6% 2 7% 4 5% 5% 4 6% 9% 41%	2800
	21st to end	Day	12% 6% 3 6% 5% 5% 5% 4 6% 9% 40%	2800
July	1st to 10th	Day	8% 6% 3 7% 5% 6% 5% 5% 7% 9% 39%	6360
	11th to 20th	Day	8% 6% 2 7% 4 4 5% 4 6% 8% 46%	6360
	21st to end	Day	9% 6% 3 8% 5% 5% 5% 4 7% 9% 38%	6924
August	1st to 10th	Day	10% 5% 3 7% 4 5% 6% 5% 7% 9% 40%	4402
	11th to 20th	Day	11% 5% 2 6% 4 4 5% 4 5% 8% 46%	3991
	21st to end	Day	9% 6% 2 6% 4 4 5% 4 7% 9% 45%	4312
September	1st to 10th	Day	13% 5% 2 7% 5% 4 4 3 6% 7% 45%	2400
	11th to 20th	Day	12% 5% 2 4 3 3 4 4 6% 8% 49%	2368
	21st to end	Day	12% 6% 3 7% 4 4 4 3 5% 7% 45%	2190
October	1st to 10th	Day	13% 6% 3 7% 4 3 3 3 4 6% 48%	2000
	11th to 20th	Day	17% 9% 3 7% 4 4 3 3 5% 6% 38%	2000
	21st to end	Day	17% 11% 3 6% 4 4 3 2 4 5% 41%	2054
November	1st to 10th	Day	10% 8% 5% 8% 4 4 3 3 6% 6% 43%	1852
	11th to 20th	Day	14% 13% 4 8% 5% 5% 4 3 5% 6% 33%	1832
	21st to end	Day	13% 14% 3 10% 5% 4 3 3 4 6% 35%	1680
December	1st to 10th	Day	8% 10% 3 9% 5% 4 5% 5% 7% 7% 38%	2690
	11th to 20th	Day	13% 13% 5% 13% 7% 6% 5% 4 5% 7% 23%	3088
	21st to end	Day	15% 22% 10% 14% 5% 4 4 3 4 5% 14%	4070
January	1st to 10th	Night	9% 11% 6% 14% 7% 5% 4 3 5% 5% 32%	8232
	11th to 20th	Night	8% 12% 5% 14% 7% 6% 6% 5% 7% 6% 23%	8280
	21st to end	Night	8% 13% 6% 10% 5% 5% 4 3 5% 6% 33%	8659
February	1st to 10th	Night	10% 13% 4 11% 7% 5% 4 4 4 5% 32%	2730
	11th to 20th	Night	10% 10% 4 7% 6% 5% 5% 4 5% 5% 39%	2567
	21st to end	Night	14% 12% 4 7% 4 4 4 3 5% 5% 37%	2076
March	1st to 10th	Night	15% 10% 3 7% 4 4 4 3 4 4 42%	5493
	11th to 20th	Night	9% 8% 2 6% 4 4 4 3 6% 7% 47%	5156
	21st to end	Night	22% 13% 5% 9% 5% 4 4 3 4 5% 26%	5105
April	1st to 10th	Night	16% 10% 2 8% 5% 3 4 4 4 6% 38%	2000
	11th to 20th	Night	18% 9% 2 7% 5% 4 4 2 5% 5% 38%	1975
	21st to end	Night	17% 8% 3 6% 5% 4 5% 4 6% 7% 36%	1975
May	1st to 10th	Night	17% 7% 3 6% 4 4 5% 4 5% 6% 41%	3728
	11th to 20th	Night	9% 7% 2 5% 4 4 5% 4 6% 7% 47%	3596
	21st to end	Night	14% 7% 2 7% 4 4 4 3 6% 8% 40%	3942
June	1st to 10th	Night	9% 4 2 5% 5% 4 5% 5% 6% 9% 46%	1600
	11th to 20th	Night	12% 6% 2 5% 3 4 4 4 5% 9% 46%	1600
	21st to end	Night	9% 7% 3 4 4 3 5% 3 6% 8% 49%	1600
July	1st to 10th	Night	12% 7% 3 5% 4 4 4 4 7% 8% 43%	3618
	11th to 20th	Night	6% 5% 2 5% 4 4 4 3 5% 8% 53%	3617
	21st to end	Night	7% 5% 2 6% 4 4 5% 3 5% 8% 50%	3947
August	1st to 10th	Night	10% 4 2 5% 3 5% 5% 4 6% 7% 50%	2754
	11th to 20th	Night	10% 5% 2 6% 4 4 4 4 5% 8% 49%	3060
	21st to end	Night	9% 5% 2 6% 4 4 4 4 5% 7% 50%	3586
September	1st to 10th	Night	9% 4 2 4 3 4 4 3 5% 7% 55%	2000
	11th to 20th	Night	10% 4 2 5% 4 4 4 3 5% 7% 52%	2011
	21st to end	Night	9% 5% 2 4 4 4 4 4 5% 6% 52%	2206
October	1st to 10th	Night	12% 6% 2 5% 3 4 4 3 5% 5% 52%	2400
	11th to 20th	Night	16% 8% 2 6% 4 3 3 4 5% 6% 43%	2400
	21st to end	Night	16% 10% 3 7% 4 4 4 4 4 7% 37%	2785
November	1st to 10th	Night	12% 8% 2 7% 4 3 3 3 5% 5% 47%	2666
	11th to 20th	Night	14% 11% 4 8% 6% 5% 5% 3 5% 6% 35%	2785
	21st to end	Night	15% 12% 4 9% 5% 3 4 3 4 6% 37%	2940
December	1st to 10th	Night	8% 8% 3 8% 5% 5% 5% 4 6% 7% 41%	4720
	11th to 20th	Night	13% 16% 6% 11% 6% 5% 5% 3 5% 5% 27%	5339
	21st to end	Night	17% 19% 7% 14% 6% 5% 4 3 4 4 16%	7150

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	63% 2 12% 15% 7%	4692
	11th to 20th	Day	50% 2 10% 17% 19% 1	4710
	21st to end	Day	49% 2 12% 26% 11%	5553
February	1st to 10th	Day	54% 2 12% 19% 11% 1	1890
	11th to 20th	Day	48% 4 10% 26% 9% 3	1948
	21st to end	Day	53% 3 9% 21% 11% 2	1730
March	1st to 10th	Day	41% 2 11% 30% 11% 4	4580
	11th to 20th	Day	39% 3 12% 32% 13% 2	5001
	21st to end	Day	59% 3 11% 16% 9% 2	5825
April	1st to 10th	Day	54% 4 10% 21% 11%	2400
	11th to 20th	Day	52% 3 9% 21% 12% 2	2374
	21st to end	Day	52% 4 11% 20% 12% 1	2423
May	1st to 10th	Day	44% 4 8% 26% 18% 1	6214
	11th to 20th	Day	40% 5% 10% 30% 14% 1	6323
	21st to end	Day	43% 4 10% 28% 12% 2	6949
June	1st to 10th	Day	36% 5% 14% 28% 16% 1	2800
	11th to 20th	Day	40% 4 14% 24% 17% 1	2800
	21st to end	Day	41% 5% 13% 26% 13% 2	2800
July	1st to 10th	Day	39% 6% 15% 31% 8% 1	6291
	11th to 20th	Day	35% 5% 13% 32% 14% 1	6285
	21st to end	Day	41% 6% 14% 22% 16% 1	6728
August	1st to 10th	Day	39% 5% 15% 27% 13% 1	4387
	11th to 20th	Day	36% 5% 13% 31% 14% 1	4030
	21st to end	Day	34% 4 13% 32% 15% 1	4311
September	1st to 10th	Day	38% 5% 11% 27% 17% 2	2400
	11th to 20th	Day	33% 4 12% 32% 16% 2	2368
	21st to end	Day	39% 4 10% 29% 18% 1	2190
October	1st to 10th	Day	25% 2 6% 40% 26% 1	3260
	11th to 20th	Day	36% 3 9% 27% 23% 3	3240
	21st to end	Day	43% 2 10% 27% 15% 2	3292
November	1st to 10th	Day	42% 3 13% 27% 13% 2	1852
	11th to 20th	Day	52% 3 11% 22% 10% 1	1832
	21st to end	Day	51% 4 14% 23% 7% 1	1680
December	1st to 10th	Day	44% 3 18% 27% 7% 1	2690
	11th to 20th	Day	61% 3 12% 16% 7% 2	3085
	21st to end	Day	75% 2 8% 10% 5%	4070
January	1st to 10th	Night	56% 2 13% 20% 8% 1	8233
	11th to 20th	Night	59% 2 10% 13% 15% 1	8280
	21st to end	Night	52% 2 11% 22% 12% 1	8659
February	1st to 10th	Night	54% 2 11% 19% 12% 2	2730
	11th to 20th	Night	47% 3 11% 24% 13% 1	2568
	21st to end	Night	50% 2 11% 23% 11% 3	2076
March	1st to 10th	Night	47% 2 11% 23% 11% 6%	5493
	11th to 20th	Night	36% 3 10% 34% 14% 3	5156
	21st to end	Night	62% 3 8% 16% 10% 1	5105
April	1st to 10th	Night	47% 3 10% 24% 15% 2	2000
	11th to 20th	Night	48% 3 8% 20% 18% 3	1975
	21st to end	Night	47% 4 12% 22% 13% 3	1975
May	1st to 10th	Night	45% 4 9% 19% 21% 2	3754
	11th to 20th	Night	36% 5% 15% 24% 19% 2	3597
	21st to end	Night	41% 6% 10% 26% 16% 2	3950
June	1st to 10th	Night	34% 5% 13% 29% 18% 1	1600
	11th to 20th	Night	36% 4 11% 26% 21% 2	1600
	21st to end	Night	35% 4 16% 23% 18% 4	1600
July	1st to 10th	Night	38% 5% 15% 27% 14% 2	3580
	11th to 20th	Night	30% 5% 14% 32% 18% 2	3572
	21st to end	Night	32% 5% 18% 23% 19% 3	3832
August	1st to 10th	Night	32% 5% 13% 30% 19% 1	2745
	11th to 20th	Night	34% 4 13% 32% 16% 1	3087
	21st to end	Night	33% 5% 13% 28% 18% 4	3586
September	1st to 10th	Night	28% 4 11% 30% 24% 2	2000
	11th to 20th	Night	33% 4 11% 33% 17% 2	2011
	21st to end	Night	33% 4 9% 30% 23% 1	2206
October	1st to 10th	Night	25% 3 5% 37% 28% 2	3920
	11th to 20th	Night	32% 3 11% 26% 26% 3	3899
	21st to end	Night	45% 3 9% 27% 15% 2	4497
November	1st to 10th	Night	39% 3 12% 27% 17% 2	2666
	11th to 20th	Night	50% 3 12% 21% 12% 2	2785
	21st to end	Night	50% 3 12% 24% 10% 1	2940
December	1st to 10th	Night	42% 2 17% 28% 9% 1	4720
	11th to 20th	Night	60% 3 11% 16% 9% 1	5341
	21st to end	Night	72% 2 7% 13% 5%	7150

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	15% 17% 34% 24% 8% 2	330
	11th to 20th	Day	18% 18% 39% 18% 5% 1	330
	21st to end	Day	20% 19% 35% 23% 3	363
February	1st to 10th	Day	17% 20% 41% 17% 5% 1	330
	11th to 20th	Day	21% 23% 35% 16% 5%	330
	21st to end	Day	22% 20% 45% 11% 2	273
March	1st to 10th	Day	19% 19% 42% 15% 4	330
	11th to 20th	Day	21% 21% 37% 15% 4 2	321
	21st to end	Day	30% 12% 32% 18% 6% 1	484
April	1st to 10th	Day	27% 16% 33% 20% 5%	500
	11th to 20th	Day	25% 19% 26% 18% 11% 1	492
	21st to end	Day	24% 16% 28% 21% 10% 1	500
May	1st to 10th	Day	20% 13% 32% 26% 8% 2	638
	11th to 20th	Day	18% 13% 28% 24% 13% 3	725
	21st to end	Day	17% 10% 27% 25% 14% 6%	789
June	1st to 10th	Day	11% 7% 27% 32% 18% 4	730
	11th to 20th	Day	13% 7% 32% 29% 15% 3	730
	21st to end	Day	14% 8% 32% 28% 14% 5%	730
July	1st to 10th	Day	8% 4 19% 32% 25% 11%	721
	11th to 20th	Day	9% 6% 26% 32% 20% 7%	718
	21st to end	Day	8% 4 28% 34% 20% 7%	794
August	1st to 10th	Day	8% 4 22% 34% 23% 9%	726
	11th to 20th	Day	14% 6% 20% 28% 22% 11%	613
	21st to end	Day	10% 8% 21% 33% 20% 8%	583
September	1st to 10th	Day	16% 7% 21% 32% 18% 7%	530
	11th to 20th	Day	12% 5% 19% 34% 23% 8%	530
	21st to end	Day	15% 8% 28% 27% 18% 4	520
October	1st to 10th	Day	15% 10% 29% 29% 15% 2	330
	11th to 20th	Day	24% 18% 32% 19% 5% 1	330
	21st to end	Day	26% 15% 32% 19% 6% 2	363
November	1st to 10th	Day	15% 20% 39% 18% 6% 2	330
	11th to 20th	Day	20% 23% 31% 19% 7% 1	330
	21st to end	Day	23% 13% 41% 20% 3	330
December	1st to 10th	Day	15% 20% 41% 17% 7% 1	330
	11th to 20th	Day	21% 13% 42% 19% 6%	330
	21st to end	Day	28% 17% 37% 15% 2 1	363
January	1st to 10th	Night	15% 17% 36% 24% 7%	1050
	11th to 20th	Night	18% 16% 38% 23% 4	1050
	21st to end	Night	19% 13% 37% 25% 5%	1155
February	1st to 10th	Night	18% 14% 37% 26% 5%	1050
	11th to 20th	Night	15% 16% 40% 25% 4	933
	21st to end	Night	21% 17% 39% 19% 4	692
March	1st to 10th	Night	20% 12% 39% 23% 5%	840
	11th to 20th	Night	18% 12% 36% 26% 7%	668
	21st to end	Night	25% 12% 31% 25% 6%	660
April	1st to 10th	Night	20% 15% 37% 23% 5%	600
	11th to 20th	Night	21% 14% 31% 28% 6%	593
	21st to end	Night	19% 9% 34% 29% 9% 1	600
May	1st to 10th	Night	19% 8% 32% 33% 7% 1	600
	11th to 20th	Night	16% 9% 30% 34% 12%	591
	21st to end	Night	14% 6% 27% 36% 15% 1	650
June	1st to 10th	Night	10% 5% 27% 43% 14% 1	600
	11th to 20th	Night	15% 5% 31% 36% 13%	600
	21st to end	Night	13% 5% 25% 41% 16% 1	600
July	1st to 10th	Night	8% 3 13% 43% 30% 2	585
	11th to 20th	Night	8% 4 20% 43% 23% 2	582
	21st to end	Night	7% 2 18% 45% 25% 2	657
August	1st to 10th	Night	7% 2 16% 47% 26% 3	597
	11th to 20th	Night	12% 2 15% 42% 23% 6%	594
	21st to end	Night	11% 3 17% 46% 20% 3	660
September	1st to 10th	Night	10% 4 22% 38% 20% 6%	600
	11th to 20th	Night	12% 3 22% 35% 24% 5%	611
	21st to end	Night	12% 7% 26% 34% 20% 1	800
October	1st to 10th	Night	15% 6% 28% 32% 18% 1	800
	11th to 20th	Night	20% 12% 32% 28% 9%	800
	21st to end	Night	20% 13% 34% 26% 8%	880
November	1st to 10th	Night	16% 12% 39% 25% 8%	820
	11th to 20th	Night	19% 17% 37% 21% 6%	895
	21st to end	Night	21% 15% 35% 23% 6%	1050
December	1st to 10th	Night	19% 15% 39% 22% 5%	1050
	11th to 20th	Night	22% 14% 36% 24% 5%	1050
	21st to end	Night	27% 15% 35% 20% 4	1155

Page generated at 2026-03-15 01:23:51. Version ac07

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