Maumee
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Maumee clear sky chart from 2005-11-06 to 2024-09-14.

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	14% 8% 3 6% 4 4 4 4 5% 7% 39%	100464
	Night	15% 9% 3 7% 4 4 4 3 5% 6% 39%	97440
Transparency	Day	44% 5% 11% 24% 15% 2	100261
	Night	45% 5% 10% 23% 14% 2	97314
Seeing	Day	20% 14% 28% 22% 12% 4	15316
	Night	20% 12% 27% 25% 13% 2	25087

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% 18% 6% 8% 4 4 4 4 4 5% 30%	2527
	11th to 20th	Day	18% 11% 4 12% 7% 5% 4 4 5% 4 28%	2530
	21st to end	Day	26% 16% 7% 7% 4 3 3 2 3 4 24%	3012
February	1st to 10th	Day	18% 12% 6% 8% 5% 4 3 3 5% 7% 31%	1900
	11th to 20th	Day	16% 10% 4 9% 5% 4 4 4 5% 6% 35%	1848
	21st to end	Day	17% 14% 4 9% 4 3 3 3 4 6% 32%	1570
March	1st to 10th	Day	24% 16% 3 6% 3 3 3 2 3 4 33%	3120
	11th to 20th	Day	15% 7% 3 6% 4 3 4 3 5% 7% 45%	3352
	21st to end	Day	15% 10% 3 8% 4 5% 5% 4 6% 7% 34%	3991
April	1st to 10th	Day	15% 9% 3 6% 5% 4 4 3 5% 8% 38%	2280
	11th to 20th	Day	18% 9% 3 6% 4 4 3 3 5% 6% 40%	2254
	21st to end	Day	20% 7% 2 7% 4 4 4 3 4 7% 38%	2418
May	1st to 10th	Day	20% 9% 3 7% 4 4 5% 4 7% 9% 29%	4082
	11th to 20th	Day	21% 7% 3 5% 4 4 3 4 5% 6% 39%	4081
	21st to end	Day	11% 7% 3 7% 5% 5% 5% 5% 6% 8% 38%	4498
June	1st to 10th	Day	12% 6% 2 6% 5% 4 4 4 6% 8% 43%	2660
	11th to 20th	Day	8% 5% 2 6% 5% 5% 5% 5% 6% 9% 45%	2660
	21st to end	Day	9% 6% 2 6% 5% 5% 5% 5% 6% 9% 42%	2660
July	1st to 10th	Day	14% 6% 2 6% 4 4 5% 4 6% 11% 38%	4440
	11th to 20th	Day	6% 4 2 5% 4 5% 5% 5% 7% 10% 48%	4440
	21st to end	Day	10% 7% 3 8% 6% 6% 7% 6% 8% 9% 31%	4608
August	1st to 10th	Day	9% 4 2 5% 4 3 5% 4 7% 10% 47%	4104
	11th to 20th	Day	9% 5% 2 6% 4 5% 6% 5% 8% 10% 41%	3802
	21st to end	Day	5% 4 2 5% 4 4 4 4 6% 9% 54%	4180
September	1st to 10th	Day	13% 6% 2 6% 4 4 4 4 5% 7% 46%	2248
	11th to 20th	Day	11% 6% 2 5% 4 4 4 3 5% 8% 47%	2014
	21st to end	Day	12% 5% 2 5% 4 3 4 3 4 7% 53%	1980
October	1st to 10th	Day	11% 5% 2 6% 4 3 4 3 5% 6% 51%	1980
	11th to 20th	Day	13% 7% 3 5% 4 4 4 4 6% 6% 45%	1864
	21st to end	Day	20% 9% 3 7% 4 4 3 3 5% 6% 37%	1782
November	1st to 10th	Day	10% 6% 2 5% 3 3 4 3 5% 7% 53%	1672
	11th to 20th	Day	16% 10% 3 6% 4 3 4 3 5% 7% 40%	1710
	21st to end	Day	19% 10% 3 6% 3 5% 3 3 4 5% 40%	1710
December	1st to 10th	Day	20% 14% 4 8% 4 4 3 3 3 5% 33%	1710
	11th to 20th	Day	16% 15% 5% 9% 4 3 4 3 4 5% 32%	1994
	21st to end	Day	23% 19% 6% 7% 5% 4 3 3 4 5% 20%	2783
January	1st to 10th	Night	18% 15% 7% 8% 4 4 4 4 5% 5% 26%	4428
	11th to 20th	Night	16% 17% 6% 14% 7% 5% 4 2 3 4 23%	4440
	21st to end	Night	25% 16% 7% 7% 4 3 3 2 3 4 25%	4628
February	1st to 10th	Night	20% 12% 5% 10% 5% 4 4 3 5% 5% 28%	2280
	11th to 20th	Night	15% 12% 5% 9% 5% 4 3 3 6% 6% 32%	2218
	21st to end	Night	20% 12% 4 8% 4 3 4 3 5% 5% 31%	1884
March	1st to 10th	Night	23% 15% 3 6% 3 3 3 3 4 5% 32%	3733
	11th to 20th	Night	13% 6% 3 6% 4 3 4 3 5% 5% 48%	3608
	21st to end	Night	16% 8% 3 7% 5% 4 4 4 5% 5% 38%	3668
April	1st to 10th	Night	14% 9% 2 6% 5% 4 4 3 7% 6% 40%	1900
	11th to 20th	Night	16% 9% 2 6% 4 3 4 4 5% 6% 41%	1875
	21st to end	Night	17% 7% 3 6% 4 3 5% 4 6% 7% 37%	1759
May	1st to 10th	Night	19% 12% 3 8% 5% 4 4 4 5% 7% 28%	2813
	11th to 20th	Night	18% 6% 2 5% 3 4 4 3 6% 7% 41%	2812
	21st to end	Night	10% 5% 2 6% 4 5% 5% 4 6% 9% 42%	3054
June	1st to 10th	Night	11% 4 2 5% 4 4 4 4 6% 8% 48%	1520
	11th to 20th	Night	8% 5% 2 6% 4 4 4 4 6% 10% 48%	1520
	21st to end	Night	6% 3 1 4 3 3 4 6% 8% 10% 51%	1520
July	1st to 10th	Night	10% 5% 2 5% 4 4 4 4 6% 8% 46%	2530
	11th to 20th	Night	5% 3 2 4 3 4 3 4 7% 10% 54%	2530
	21st to end	Night	9% 6% 2 8% 5% 6% 6% 5% 7% 10% 36%	2934
August	1st to 10th	Night	9% 5% 2 5% 4 4 4 3 5% 9% 51%	2825
	11th to 20th	Night	8% 5% 2 6% 5% 5% 4 4 6% 9% 47%	3024
	21st to end	Night	4 2 1 4 3 3 5% 4 6% 9% 59%	3476
September	1st to 10th	Night	11% 4 2 5% 4 4 4 3 4 7% 51%	1912
	11th to 20th	Night	8% 4 1 5% 3 3 4 3 5% 8% 55%	2024
	21st to end	Night	12% 6% 2 4 4 3 4 3 4 7% 52%	1980
October	1st to 10th	Night	9% 4 1 4 4 3 3 3 5% 6% 57%	1980
	11th to 20th	Night	16% 6% 2 6% 3 3 4 3 4 7% 46%	2093
	21st to end	Night	18% 9% 3 6% 4 3 4 3 5% 5% 42%	2574
November	1st to 10th	Night	13% 7% 2 5% 3 3 3 3 4 7% 49%	2406
	11th to 20th	Night	16% 9% 3 7% 4 3 4 3 4 6% 42%	2470
	21st to end	Night	19% 11% 4 7% 5% 3 4 2 4 6% 36%	2470
December	1st to 10th	Night	18% 12% 4 8% 5% 4 4 3 4 5% 32%	2470
	11th to 20th	Night	18% 13% 4 9% 4 4 3 3 5% 5% 32%	3198
	21st to end	Night	23% 19% 5% 9% 5% 4 4 2 4 4 19%	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	56% 3 10% 21% 9% 1	2528
	11th to 20th	Day	59% 4 9% 18% 9%	2530
	21st to end	Day	66% 3 9% 18% 3 1	3012
February	1st to 10th	Day	54% 3 8% 22% 11% 2	1900
	11th to 20th	Day	50% 4 9% 24% 11% 2	1858
	21st to end	Day	54% 4 9% 21% 10% 3	1570
March	1st to 10th	Day	57% 3 6% 19% 11% 4	3120
	11th to 20th	Day	41% 4 9% 30% 15% 2	3352
	21st to end	Day	48% 5% 13% 22% 11% 1	3991
April	1st to 10th	Day	44% 5% 12% 23% 15% 1	2280
	11th to 20th	Day	45% 4 9% 24% 14% 3	2254
	21st to end	Day	47% 5% 9% 23% 13% 3	2418
May	1st to 10th	Day	50% 6% 14% 22% 8%	4120
	11th to 20th	Day	47% 5% 11% 24% 13%	4085
	21st to end	Day	41% 7% 11% 19% 19% 2	4511
June	1st to 10th	Day	38% 6% 11% 25% 16% 4	2660
	11th to 20th	Day	35% 6% 13% 23% 20% 3	2660
	21st to end	Day	37% 8% 14% 20% 17% 4	2660
July	1st to 10th	Day	41% 5% 12% 22% 18% 2	4371
	11th to 20th	Day	28% 7% 12% 31% 20% 1	4365
	21st to end	Day	45% 8% 15% 17% 13% 2	4462
August	1st to 10th	Day	30% 6% 15% 33% 15% 1	4091
	11th to 20th	Day	35% 5% 12% 31% 17% 1	3840
	21st to end	Day	26% 5% 14% 34% 17% 4	4179
September	1st to 10th	Day	36% 6% 10% 25% 18% 5%	2248
	11th to 20th	Day	34% 4 12% 27% 19% 4	2014
	21st to end	Day	32% 4 10% 26% 26% 2	1980
October	1st to 10th	Day	34% 5% 10% 26% 23% 2	1980
	11th to 20th	Day	37% 4 9% 25% 21% 3	1864
	21st to end	Day	48% 3 9% 24% 14% 2	1782
November	1st to 10th	Day	32% 4 10% 32% 18% 4	1672
	11th to 20th	Day	44% 5% 9% 22% 17% 4	1710
	21st to end	Day	47% 3 9% 23% 16% 1	1710
December	1st to 10th	Day	56% 4 9% 19% 11% 1	1710
	11th to 20th	Day	55% 4 7% 22% 11% 1	1991
	21st to end	Day	65% 4 9% 13% 7% 1	2783
January	1st to 10th	Night	58% 5% 11% 17% 8%	4428
	11th to 20th	Night	65% 4 9% 14% 8%	4440
	21st to end	Night	64% 3 7% 16% 9% 1	4628
February	1st to 10th	Night	58% 4 11% 19% 7% 1	2280
	11th to 20th	Night	52% 4 10% 21% 13% 1	2219
	21st to end	Night	54% 4 10% 17% 11% 2	1884
March	1st to 10th	Night	54% 4 6% 23% 12% 1	3733
	11th to 20th	Night	36% 6% 12% 24% 21% 1	3608
	21st to end	Night	47% 4 9% 28% 10% 1	3668
April	1st to 10th	Night	42% 5% 10% 26% 14% 3	1900
	11th to 20th	Night	43% 5% 9% 19% 19% 5%	1875
	21st to end	Night	44% 6% 10% 24% 13% 3	1759
May	1st to 10th	Night	55% 6% 11% 20% 6% 2	2840
	11th to 20th	Night	42% 6% 13% 28% 10% 1	2813
	21st to end	Night	36% 8% 15% 23% 14% 4	3062
June	1st to 10th	Night	33% 6% 11% 25% 21% 4	1520
	11th to 20th	Night	31% 6% 13% 24% 21% 6%	1520
	21st to end	Night	24% 8% 17% 25% 20% 5%	1520
July	1st to 10th	Night	35% 7% 10% 26% 18% 4	2490
	11th to 20th	Night	24% 6% 13% 34% 20% 2	2482
	21st to end	Night	40% 7% 14% 24% 12% 3	2840
August	1st to 10th	Night	31% 6% 14% 36% 12% 1	2814
	11th to 20th	Night	31% 7% 14% 29% 18% 1	3052
	21st to end	Night	22% 6% 14% 31% 23% 3	3476
September	1st to 10th	Night	33% 5% 10% 26% 19% 7%	1912
	11th to 20th	Night	28% 6% 10% 27% 25% 4	2024
	21st to end	Night	32% 4 10% 24% 25% 4	1980
October	1st to 10th	Night	28% 4 11% 26% 26% 5%	1980
	11th to 20th	Night	39% 4 8% 25% 20% 4	2093
	21st to end	Night	45% 4 8% 23% 17% 3	2574
November	1st to 10th	Night	36% 4 9% 25% 22% 4	2406
	11th to 20th	Night	42% 5% 9% 21% 19% 4	2470
	21st to end	Night	51% 3 10% 22% 14% 1	2470
December	1st to 10th	Night	54% 4 10% 20% 11% 1	2470
	11th to 20th	Night	54% 4 9% 20% 13% 1	3200
	21st to end	Night	69% 4 8% 12% 6% 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	32% 21% 28% 17% 1 1	270
	11th to 20th	Day	36% 26% 29% 8% 1	270
	21st to end	Day	32% 27% 30% 9% 2	297
February	1st to 10th	Day	31% 29% 26% 11% 1	270
	11th to 20th	Day	30% 28% 31% 9% 1	270
	21st to end	Day	32% 25% 36% 8%	225
March	1st to 10th	Day	33% 25% 33% 9% 1	270
	11th to 20th	Day	33% 21% 30% 12% 4 1	384
	21st to end	Day	32% 21% 30% 13% 3 1	506
April	1st to 10th	Day	27% 18% 31% 18% 5% 1	460
	11th to 20th	Day	25% 23% 24% 20% 7% 2	452
	21st to end	Day	28% 21% 33% 10% 7% 2	460
May	1st to 10th	Day	26% 17% 31% 17% 6% 3	463
	11th to 20th	Day	24% 14% 29% 20% 9% 5%	487
	21st to end	Day	14% 12% 29% 22% 16% 7%	538
June	1st to 10th	Day	14% 9% 30% 27% 15% 5%	680
	11th to 20th	Day	10% 8% 28% 33% 16% 5%	680
	21st to end	Day	13% 9% 32% 25% 16% 6%	680
July	1st to 10th	Day	14% 5% 20% 27% 21% 13%	671
	11th to 20th	Day	7% 6% 27% 32% 20% 8%	668
	21st to end	Day	9% 5% 23% 35% 20% 7%	622
August	1st to 10th	Day	10% 4 19% 34% 23% 10%	486
	11th to 20th	Day	16% 5% 26% 28% 20% 5%	479
	21st to end	Day	9% 4 17% 33% 27% 10%	539
September	1st to 10th	Day	12% 6% 20% 32% 22% 8%	490
	11th to 20th	Day	14% 1 17% 32% 25% 11%	463
	21st to end	Day	17% 9% 21% 26% 22% 6%	450
October	1st to 10th	Day	12% 8% 33% 28% 15% 4	450
	11th to 20th	Day	17% 20% 34% 19% 9% 1	392
	21st to end	Day	33% 14% 38% 15%	297
November	1st to 10th	Day	15% 20% 31% 25% 6% 3	270
	11th to 20th	Day	26% 20% 30% 18% 6% 1	270
	21st to end	Day	29% 15% 36% 16% 4 1	270
December	1st to 10th	Day	28% 25% 29% 13% 4 1	270
	11th to 20th	Day	29% 19% 35% 13% 3 1	270
	21st to end	Day	36% 22% 29% 10% 3	297
January	1st to 10th	Night	27% 21% 30% 18% 3	950
	11th to 20th	Night	30% 21% 32% 15% 2	950
	21st to end	Night	26% 21% 33% 19% 2	931
February	1st to 10th	Night	30% 16% 35% 18% 2	760
	11th to 20th	Night	25% 24% 32% 17% 2	743
	21st to end	Night	30% 18% 36% 15% 1	628
March	1st to 10th	Night	26% 20% 30% 21% 2	760
	11th to 20th	Night	25% 19% 32% 18% 5%	760
	21st to end	Night	26% 16% 29% 24% 5%	751
April	1st to 10th	Night	19% 16% 34% 24% 6% 1	570
	11th to 20th	Night	22% 15% 29% 24% 9% 1	563
	21st to end	Night	21% 12% 36% 24% 6% 1	570
May	1st to 10th	Night	21% 11% 32% 26% 10%	570
	11th to 20th	Night	15% 10% 27% 28% 17% 3	561
	21st to end	Night	11% 5% 26% 31% 22% 4	617
June	1st to 10th	Night	12% 5% 24% 35% 22% 1	570
	11th to 20th	Night	9% 5% 23% 41% 21% 1	570
	21st to end	Night	7% 3 26% 37% 25% 2	570
July	1st to 10th	Night	12% 2 14% 34% 29% 10%	555
	11th to 20th	Night	9% 3 16% 35% 32% 5%	552
	21st to end	Night	8% 2 16% 40% 30% 4	624
August	1st to 10th	Night	8% 2 14% 37% 34% 5%	567
	11th to 20th	Night	8% 2 16% 37% 33% 5%	564
	21st to end	Night	6% 2 17% 32% 36% 7%	627
September	1st to 10th	Night	13% 4 14% 33% 32% 4	582
	11th to 20th	Night	9% 3 18% 31% 33% 5%	736
	21st to end	Night	15% 7% 22% 29% 24% 3	720
October	1st to 10th	Night	11% 7% 26% 29% 21% 5%	720
	11th to 20th	Night	19% 12% 29% 25% 13% 2	720
	21st to end	Night	23% 14% 32% 22% 8% 1	792
November	1st to 10th	Night	17% 12% 30% 27% 13% 1	740
	11th to 20th	Night	24% 17% 27% 24% 8%	760
	21st to end	Night	26% 17% 24% 26% 6%	760
December	1st to 10th	Night	27% 17% 32% 19% 5%	760
	11th to 20th	Night	27% 16% 30% 22% 5% 1	869
	21st to end	Night	34% 17% 29% 16% 3	1045

Page generated at 2024-09-11 10:00:04. Version ac07

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