Middleville
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Middleville clear sky chart from 2005-11-06 to 2024-12-24.

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	17% 7% 2 6% 4 4 4 4 5% 7% 37%	101768
	Night	17% 8% 3 6% 4 4 4 3 5% 6% 40%	98306
Transparency	Day	44% 7% 12% 22% 14% 2	105300
	Night	42% 7% 12% 23% 14% 2	102863
Seeing	Day	24% 16% 29% 19% 9% 3	15037
	Night	21% 15% 29% 25% 9% 1	24301

By Month

Percentage Cloud Cover NE (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	15% 10% 3 6% 4 3 4 3 4 4 44%	2517
	11th to 20th	Day	15% 12% 4 9% 6% 6% 4 3 5% 6% 32%	2520
	21st to end	Day	21% 11% 4 7% 4 4 4 3 4 5% 32%	3074
February	1st to 10th	Day	17% 8% 2 9% 5% 5% 4 3 5% 6% 35%	1710
	11th to 20th	Day	15% 9% 3 7% 4 4 4 3 6% 5% 39%	1802
	21st to end	Day	19% 9% 3 8% 5% 4 4 3 5% 5% 36%	1570
March	1st to 10th	Day	27% 10% 3 6% 4 3 2 3 3 5% 34%	3116
	11th to 20th	Day	11% 8% 2 7% 5% 5% 4 4 6% 7% 41%	3434
	21st to end	Day	21% 8% 2 5% 4 3 3 2 4 5% 42%	4070
April	1st to 10th	Day	18% 9% 3 6% 4 4 4 4 5% 6% 36%	2280
	11th to 20th	Day	18% 7% 3 6% 4 4 4 3 5% 6% 40%	2254
	21st to end	Day	18% 7% 2 6% 4 5% 5% 5% 6% 6% 38%	2280
May	1st to 10th	Day	28% 7% 2 6% 4 4 4 3 5% 7% 30%	4163
	11th to 20th	Day	23% 9% 3 7% 5% 5% 4 3 5% 6% 28%	4398
	21st to end	Day	13% 5% 2 5% 4 4 5% 4 6% 9% 43%	4837
June	1st to 10th	Day	15% 5% 3 6% 5% 5% 6% 5% 6% 8% 36%	2660
	11th to 20th	Day	16% 6% 3 6% 5% 5% 5% 4 7% 10% 33%	2660
	21st to end	Day	13% 6% 2 6% 5% 5% 5% 3 6% 8% 40%	2660
July	1st to 10th	Day	9% 6% 3 8% 5% 6% 6% 5% 7% 10% 35%	4440
	11th to 20th	Day	10% 6% 2 6% 5% 5% 5% 5% 7% 11% 38%	4440
	21st to end	Day	14% 9% 3 8% 6% 5% 5% 4 6% 7% 33%	4814
August	1st to 10th	Day	21% 6% 2 7% 4 5% 5% 4 7% 7% 30%	4151
	11th to 20th	Day	13% 6% 2 6% 5% 4 5% 4 6% 9% 40%	3739
	21st to end	Day	13% 6% 2 5% 3 4 4 4 5% 9% 45%	4180
September	1st to 10th	Day	16% 6% 2 6% 4 4 4 4 5% 7% 43%	2280
	11th to 20th	Day	13% 5% 2 5% 4 4 4 3 5% 6% 50%	2234
	21st to end	Day	19% 6% 3 7% 4 3 4 4 5% 6% 39%	2090
October	1st to 10th	Day	19% 6% 2 7% 4 3 4 3 4 7% 40%	1924
	11th to 20th	Day	15% 6% 2 6% 4 4 4 3 4 7% 45%	1900
	21st to end	Day	21% 6% 2 5% 4 3 4 3 5% 6% 40%	1978
November	1st to 10th	Day	14% 7% 2 4 3 3 2 2 4 6% 52%	1761
	11th to 20th	Day	18% 8% 2 5% 3 3 4 3 5% 7% 44%	1800
	21st to end	Day	17% 8% 2 5% 4 4 5% 4 5% 7% 38%	1650
December	1st to 10th	Day	19% 9% 3 7% 5% 5% 4 3 4 6% 36%	1600
	11th to 20th	Day	21% 8% 2 6% 5% 3 4 3 5% 5% 37%	1986
	21st to end	Day	19% 11% 5% 10% 6% 5% 5% 3 5% 6% 25%	2796
January	1st to 10th	Night	17% 9% 2 6% 4 4 4 4 5% 6% 41%	4429
	11th to 20th	Night	15% 10% 4 8% 5% 4 4 3 5% 6% 35%	4440
	21st to end	Night	23% 11% 3 7% 4 4 3 3 4 5% 32%	4565
February	1st to 10th	Night	16% 9% 3 6% 5% 3 4 3 5% 6% 40%	2470
	11th to 20th	Night	16% 8% 3 7% 5% 4 5% 3 5% 5% 39%	2262
	21st to end	Night	19% 6% 4 6% 5% 4 3 3 5% 5% 39%	1884
March	1st to 10th	Night	22% 12% 3 6% 4 3 3 2 4 5% 36%	3724
	11th to 20th	Night	11% 9% 2 6% 4 4 4 4 5% 7% 44%	3523
	21st to end	Night	17% 10% 3 7% 3 4 4 3 4 4 42%	3548
April	1st to 10th	Night	18% 8% 2 7% 6% 5% 4 4 5% 6% 35%	1900
	11th to 20th	Night	18% 6% 3 6% 4 4 4 3 6% 8% 38%	1875
	21st to end	Night	19% 7% 2 5% 3 3 3 4 5% 7% 41%	1900
May	1st to 10th	Night	28% 8% 2 6% 4 4 3 3 4 7% 30%	2791
	11th to 20th	Night	24% 9% 3 7% 4 4 4 3 5% 6% 32%	2495
	21st to end	Night	14% 7% 2 6% 4 4 5% 4 6% 8% 40%	2738
June	1st to 10th	Night	16% 6% 1 5% 4 5% 5% 3 5% 6% 44%	1520
	11th to 20th	Night	13% 6% 2 5% 5% 4 4 4 6% 9% 41%	1520
	21st to end	Night	13% 4 2 5% 3 4 5% 4 6% 9% 44%	1520
July	1st to 10th	Night	10% 6% 2 6% 5% 5% 7% 4 6% 10% 40%	2520
	11th to 20th	Night	11% 6% 2 6% 4 5% 5% 4 8% 11% 38%	2520
	21st to end	Night	16% 7% 2 6% 4 4 6% 5% 6% 7% 38%	2739
August	1st to 10th	Night	21% 7% 3 7% 4 5% 5% 4 5% 8% 32%	2761
	11th to 20th	Night	15% 7% 3 6% 4 5% 4 3 5% 7% 42%	3058
	21st to end	Night	13% 4 2 4 3 3 4 3 6% 8% 50%	3476
September	1st to 10th	Night	15% 6% 2 6% 4 4 4 3 5% 7% 46%	1900
	11th to 20th	Night	12% 6% 2 5% 3 3 3 2 4 7% 53%	1945
	21st to end	Night	17% 6% 2 6% 5% 3 3 3 4 6% 44%	2090
October	1st to 10th	Night	22% 6% 3 5% 4 4 3 2 4 6% 42%	2252
	11th to 20th	Night	17% 6% 2 5% 4 3 3 2 4 6% 48%	2280
	21st to end	Night	21% 7% 2 5% 3 3 2 3 5% 6% 43%	2618
November	1st to 10th	Night	13% 5% 2 6% 3 4 4 3 5% 6% 51%	2537
	11th to 20th	Night	18% 7% 3 5% 3 3 4 3 4 5% 45%	2600
	21st to end	Night	14% 7% 3 6% 4 3 4 4 5% 7% 43%	2745
December	1st to 10th	Night	19% 9% 2 6% 5% 5% 4 3 5% 6% 36%	2800
	11th to 20th	Night	19% 9% 3 5% 4 4 4 4 5% 6% 36%	3428
	21st to end	Night	21% 11% 4 8% 5% 4 4 3 4 6% 32%	4933

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	42% 6% 12% 29% 9% 2	2518
	11th to 20th	Day	52% 7% 12% 19% 9% 2	2520
	21st to end	Day	53% 7% 11% 19% 9% 1	3074
February	1st to 10th	Day	49% 6% 13% 20% 12% 1	1710
	11th to 20th	Day	46% 7% 9% 22% 15% 2	1811
	21st to end	Day	50% 5% 10% 21% 11% 3	1570
March	1st to 10th	Day	53% 5% 9% 23% 8% 2	3119
	11th to 20th	Day	36% 9% 16% 27% 11% 2	3434
	21st to end	Day	45% 5% 9% 14% 23% 5%	4070
April	1st to 10th	Day	47% 6% 10% 20% 14% 4	2280
	11th to 20th	Day	44% 6% 11% 20% 16% 3	2254
	21st to end	Day	43% 8% 10% 20% 14% 4	2280
May	1st to 10th	Day	53% 7% 12% 16% 11% 2	4177
	11th to 20th	Day	54% 9% 10% 17% 8% 1	4402
	21st to end	Day	34% 9% 14% 25% 16% 2	4837
June	1st to 10th	Day	43% 10% 13% 20% 13% 1	2660
	11th to 20th	Day	44% 9% 14% 22% 10% 2	2660
	21st to end	Day	41% 8% 13% 24% 14%	2660
July	1st to 10th	Day	43% 10% 12% 21% 14% 1	4370
	11th to 20th	Day	39% 7% 18% 22% 13% 1	4365
	21st to end	Day	49% 7% 11% 17% 15% 1	4661
August	1st to 10th	Day	50% 8% 13% 19% 9%	4137
	11th to 20th	Day	39% 7% 15% 28% 11%	3775
	21st to end	Day	35% 7% 11% 31% 15% 2	4180
September	1st to 10th	Day	41% 6% 12% 21% 18% 2	2280
	11th to 20th	Day	34% 5% 11% 22% 24% 3	2234
	21st to end	Day	44% 7% 11% 17% 18% 2	2090
October	1st to 10th	Day	42% 6% 7% 19% 22% 4	3197
	11th to 20th	Day	31% 5% 9% 28% 24% 3	3140
	21st to end	Day	29% 4 16% 25% 22% 3	3242
November	1st to 10th	Day	35% 4 13% 25% 19% 3	1761
	11th to 20th	Day	40% 5% 11% 24% 17% 3	1800
	21st to end	Day	43% 6% 14% 25% 10% 2	1650
December	1st to 10th	Day	50% 6% 15% 17% 12% 1	1600
	11th to 20th	Day	46% 7% 16% 22% 9% 1	1986
	21st to end	Day	56% 9% 11% 16% 8%	2796
January	1st to 10th	Night	41% 7% 13% 27% 10% 3	4429
	11th to 20th	Night	47% 7% 13% 21% 9% 2	4440
	21st to end	Night	52% 6% 10% 21% 10% 1	4565
February	1st to 10th	Night	44% 6% 14% 22% 12% 2	2470
	11th to 20th	Night	46% 5% 11% 20% 15% 4	2264
	21st to end	Night	45% 6% 9% 23% 14% 3	1884
March	1st to 10th	Night	50% 5% 11% 21% 11% 2	3734
	11th to 20th	Night	36% 8% 15% 26% 14% 2	3524
	21st to end	Night	44% 5% 8% 18% 21% 5%	3548
April	1st to 10th	Night	48% 6% 11% 19% 13% 3	1900
	11th to 20th	Night	44% 8% 9% 21% 18% 1	1875
	21st to end	Night	41% 8% 10% 21% 16% 4	1900
May	1st to 10th	Night	53% 8% 10% 20% 9% 1	2797
	11th to 20th	Night	51% 9% 14% 14% 10% 1	2496
	21st to end	Night	37% 11% 15% 24% 11% 2	2739
June	1st to 10th	Night	39% 7% 12% 23% 18% 1	1520
	11th to 20th	Night	38% 9% 16% 25% 11% 1	1520
	21st to end	Night	33% 9% 16% 27% 13% 1	1520
July	1st to 10th	Night	39% 10% 15% 19% 15% 2	2480
	11th to 20th	Night	37% 9% 16% 25% 12% 1	2472
	21st to end	Night	42% 8% 15% 16% 18% 2	2651
August	1st to 10th	Night	50% 8% 16% 17% 9% 1	2751
	11th to 20th	Night	42% 7% 14% 27% 10%	3088
	21st to end	Night	33% 6% 11% 33% 17% 1	3476
September	1st to 10th	Night	38% 6% 11% 25% 19% 1	1900
	11th to 20th	Night	34% 4 10% 23% 25% 3	1945
	21st to end	Night	40% 6% 10% 22% 21% 1	2090
October	1st to 10th	Night	43% 5% 10% 22% 18% 1	3759
	11th to 20th	Night	29% 5% 10% 27% 27% 2	3779
	21st to end	Night	30% 5% 14% 31% 19% 1	4304
November	1st to 10th	Night	34% 6% 13% 24% 21% 3	2537
	11th to 20th	Night	41% 5% 11% 22% 18% 3	2600
	21st to end	Night	40% 5% 15% 26% 12% 1	2745
December	1st to 10th	Night	47% 7% 13% 23% 10% 1	2800
	11th to 20th	Night	45% 7% 13% 20% 13% 2	3428
	21st to end	Night	50% 8% 13% 20% 8%	4933

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	32% 26% 27% 13% 2 1	180
	11th to 20th	Day	38% 27% 26% 8% 2	180
	21st to end	Day	26% 31% 30% 7% 4 1	285
February	1st to 10th	Day	33% 29% 29% 7% 2	270
	11th to 20th	Day	35% 26% 29% 9% 1	410
	21st to end	Day	34% 23% 30% 10% 3	382
March	1st to 10th	Day	31% 21% 31% 13% 3	460
	11th to 20th	Day	31% 24% 29% 12% 3 1	460
	21st to end	Day	33% 23% 28% 11% 4 1	506
April	1st to 10th	Day	32% 22% 28% 13% 5%	460
	11th to 20th	Day	29% 22% 28% 13% 7% 2	452
	21st to end	Day	30% 17% 33% 14% 4 2	460
May	1st to 10th	Day	34% 19% 27% 12% 7% 1	463
	11th to 20th	Day	22% 19% 32% 18% 7% 1	487
	21st to end	Day	19% 11% 30% 25% 12% 2	529
June	1st to 10th	Day	19% 13% 32% 23% 11% 2	490
	11th to 20th	Day	19% 14% 28% 27% 11% 2	490
	21st to end	Day	16% 13% 33% 26% 11% 1	490
July	1st to 10th	Day	13% 9% 29% 26% 18% 5%	485
	11th to 20th	Day	12% 6% 27% 33% 19% 3	484
	21st to end	Day	14% 11% 35% 26% 12% 3	532
August	1st to 10th	Day	14% 8% 29% 29% 14% 6%	486
	11th to 20th	Day	12% 8% 27% 32% 15% 6%	479
	21st to end	Day	13% 10% 32% 23% 14% 8%	539
September	1st to 10th	Day	20% 11% 26% 24% 14% 6%	490
	11th to 20th	Day	13% 10% 28% 23% 15% 10%	490
	21st to end	Day	24% 11% 29% 21% 11% 3	490
October	1st to 10th	Day	26% 11% 25% 20% 13% 4	490
	11th to 20th	Day	21% 16% 31% 21% 8% 2	490
	21st to end	Day	27% 16% 29% 18% 8% 2	479
November	1st to 10th	Day	19% 21% 28% 21% 9% 2	395
	11th to 20th	Day	26% 20% 29% 19% 6% 1	400
	21st to end	Day	27% 24% 31% 14% 4	250
December	1st to 10th	Day	31% 28% 28% 8% 6%	200
	11th to 20th	Day	40% 21% 26% 10% 4	200
	21st to end	Day	32% 17% 34% 11% 4 1	204
January	1st to 10th	Night	23% 22% 36% 16% 3	760
	11th to 20th	Night	28% 20% 30% 20% 3	760
	21st to end	Night	20% 23% 36% 19% 2	836
February	1st to 10th	Night	25% 19% 35% 19% 2	760
	11th to 20th	Night	27% 23% 36% 13% 1	743
	21st to end	Night	30% 19% 33% 16% 2	628
March	1st to 10th	Night	26% 21% 33% 18% 3	760
	11th to 20th	Night	27% 22% 30% 18% 4	760
	21st to end	Night	23% 22% 34% 15% 5% 1	836
April	1st to 10th	Night	25% 21% 32% 18% 4	760
	11th to 20th	Night	23% 18% 32% 22% 5%	751
	21st to end	Night	24% 16% 31% 24% 5%	760
May	1st to 10th	Night	27% 13% 30% 24% 6%	553
	11th to 20th	Night	18% 13% 35% 27% 7% 1	374
	21st to end	Night	16% 7% 26% 38% 12%	411
June	1st to 10th	Night	17% 7% 27% 35% 14% 1	380
	11th to 20th	Night	13% 6% 32% 37% 13%	380
	21st to end	Night	14% 5% 24% 46% 11%	380
July	1st to 10th	Night	13% 5% 24% 37% 20% 1	370
	11th to 20th	Night	12% 4 20% 45% 18% 1	368
	21st to end	Night	11% 5% 23% 43% 17% 1	416
August	1st to 10th	Night	13% 2 21% 39% 22% 2	529
	11th to 20th	Night	13% 5% 19% 37% 24% 2	723
	21st to end	Night	14% 5% 21% 36% 20% 2	836
September	1st to 10th	Night	18% 6% 25% 34% 16% 2	760
	11th to 20th	Night	14% 7% 24% 31% 20% 5%	760
	21st to end	Night	20% 6% 26% 29% 17% 2	760
October	1st to 10th	Night	24% 10% 22% 28% 14% 2	760
	11th to 20th	Night	20% 12% 29% 31% 8% 1	760
	21st to end	Night	25% 14% 31% 22% 8%	836
November	1st to 10th	Night	17% 16% 31% 25% 10% 1	780
	11th to 20th	Night	24% 16% 29% 24% 6% 1	800
	21st to end	Night	20% 21% 32% 22% 6%	800
December	1st to 10th	Night	26% 17% 32% 19% 5%	800
	11th to 20th	Night	25% 19% 32% 21% 3	800
	21st to end	Night	25% 18% 34% 20% 2	851

Page generated at 2024-12-21 04:13:50. Version ac07

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