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 2025-02-21.

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% 9% 3 7% 4 4 4 4 5% 7% 39%	108477
	Night	15% 10% 3 7% 4 4 4 3 5% 6% 38%	110214
Transparency	Day	43% 5% 11% 24% 15% 2	112132
	Night	45% 5% 10% 22% 16% 2	114699
Seeing	Day	20% 14% 28% 22% 12% 4	15828
	Night	20% 13% 27% 25% 13% 2	25766

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% 16% 6% 10% 3 4 4 4 5% 5% 30%	3617
	11th to 20th	Day	14% 12% 6% 14% 7% 4 3 3 4 4 30%	3620
	21st to end	Day	20% 12% 6% 9% 5% 4 4 3 4 4 30%	4317
February	1st to 10th	Day	18% 12% 6% 8% 5% 4 3 3 5% 7% 31%	2000
	11th to 20th	Day	16% 10% 4 9% 5% 4 4 4 5% 5% 34%	1948
	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 4 6% 9% 48%	2090
	21st to end	Day	13% 5% 2 5% 4 3 4 3 5% 6% 50%	2090
October	1st to 10th	Day	11% 5% 2 5% 4 3 4 3 5% 6% 53%	2090
	11th to 20th	Day	13% 7% 3 5% 4 4 4 4 6% 6% 46%	1966
	21st to end	Day	19% 8% 3 6% 4 5% 3 3 5% 6% 38%	1881
November	1st to 10th	Day	10% 6% 2 5% 3 3 4 3 5% 7% 52%	1762
	11th to 20th	Day	16% 10% 3 6% 4 3 4 3 5% 7% 40%	1800
	21st to end	Day	19% 10% 3 6% 3 5% 3 3 4 5% 39%	1800
December	1st to 10th	Day	15% 12% 3 6% 3 3 3 3 4 5% 43%	2930
	11th to 20th	Day	16% 13% 5% 9% 5% 5% 5% 4 4 5% 29%	3136
	21st to end	Day	25% 18% 6% 8% 4 4 4 3 4 5% 19%	3982
January	1st to 10th	Night	17% 15% 7% 10% 5% 5% 4 4 5% 5% 23%	6348
	11th to 20th	Night	14% 16% 7% 13% 6% 5% 5% 2 3 4 23%	6360
	21st to end	Night	20% 12% 5% 7% 5% 4 4 3 4 4 32%	6628
February	1st to 10th	Night	20% 12% 5% 9% 5% 4 4 3 5% 5% 27%	2400
	11th to 20th	Night	16% 12% 5% 9% 5% 4 3 3 5% 6% 31%	2338
	21st to end	Night	20% 12% 4 8% 4 3 4 3 5% 5% 32%	1885
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	7% 4 1 5% 3 3 4 3 6% 8% 55%	2090
	21st to end	Night	14% 6% 2 4 4 3 4 3 4 7% 50%	2090
October	1st to 10th	Night	9% 4 1 4 3 3 3 3 5% 6% 59%	2090
	11th to 20th	Night	15% 6% 2 6% 3 3 4 3 4 6% 48%	2211
	21st to end	Night	18% 8% 2 6% 4 3 4 3 5% 5% 43%	2717
November	1st to 10th	Night	13% 7% 2 5% 4 3 3 3 4 6% 49%	2536
	11th to 20th	Night	16% 9% 3 6% 4 3 4 3 4 6% 42%	2600
	21st to end	Night	19% 11% 4 7% 5% 3 4 3 4 6% 35%	2600
December	1st to 10th	Night	18% 11% 3 8% 4 3 3 3 3 4 40%	4250
	11th to 20th	Night	19% 12% 5% 10% 5% 4 4 3 5% 5% 29%	5062
	21st to end	Night	27% 18% 6% 9% 5% 4 4 2 4 4 18%	6996

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% 2 8% 23% 9% 1	3618
	11th to 20th	Day	57% 3 7% 16% 13% 3	3620
	21st to end	Day	59% 3 8% 20% 6% 5%	4317
February	1st to 10th	Day	54% 3 8% 22% 10% 2	2000
	11th to 20th	Day	51% 4 9% 23% 12% 2	1958
	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	33% 4 12% 28% 19% 4	2090
	21st to end	Day	35% 4 9% 25% 24% 2	2090
October	1st to 10th	Day	22% 3 6% 31% 36% 1	3480
	11th to 20th	Day	28% 4 9% 28% 29% 2	3234
	21st to end	Day	37% 3 9% 24% 25% 2	3081
November	1st to 10th	Day	32% 4 10% 31% 18% 4	1762
	11th to 20th	Day	44% 5% 8% 22% 17% 4	1800
	21st to end	Day	48% 4 9% 22% 16% 1	1800
December	1st to 10th	Day	45% 3 10% 28% 15%	2930
	11th to 20th	Day	57% 4 8% 20% 9% 1	3133
	21st to end	Day	67% 4 10% 12% 6%	3982
January	1st to 10th	Night	60% 5% 9% 17% 8%	6348
	11th to 20th	Night	65% 4 8% 12% 9% 3	6360
	21st to end	Night	55% 3 7% 22% 12% 1	6628
February	1st to 10th	Night	58% 5% 11% 18% 7% 1	2400
	11th to 20th	Night	54% 4 9% 20% 12% 1	2339
	21st to end	Night	54% 4 10% 17% 11% 2	1885
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	27% 6% 10% 27% 27% 4	2090
	21st to end	Night	34% 4 10% 23% 24% 4	2090
October	1st to 10th	Night	19% 3 7% 21% 47% 4	3480
	11th to 20th	Night	26% 2 7% 25% 36% 3	3682
	21st to end	Night	33% 3 8% 24% 27% 5%	4467
November	1st to 10th	Night	36% 4 9% 25% 22% 4	2536
	11th to 20th	Night	43% 4 9% 22% 19% 4	2600
	21st to end	Night	52% 3 10% 21% 13% 1	2600
December	1st to 10th	Night	49% 3 10% 24% 13%	4250
	11th to 20th	Night	56% 4 10% 18% 11% 1	5064
	21st to end	Night	70% 4 8% 13% 5%	6996

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	33% 21% 28% 16% 1 1	300
	11th to 20th	Day	36% 25% 30% 7% 1	300
	21st to end	Day	31% 28% 30% 9% 2	330
February	1st to 10th	Day	31% 30% 27% 11% 1	300
	11th to 20th	Day	31% 30% 29% 8% 1	300
	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	13% 1 17% 33% 25% 11%	490
	21st to end	Day	19% 10% 21% 24% 20% 6%	490
October	1st to 10th	Day	11% 8% 31% 29% 17% 4	490
	11th to 20th	Day	16% 19% 33% 20% 9% 2	428
	21st to end	Day	30% 14% 38% 17% 1	330
November	1st to 10th	Day	15% 19% 33% 24% 5% 3	300
	11th to 20th	Day	26% 21% 30% 16% 5% 1	300
	21st to end	Day	31% 16% 34% 15% 3 1	300
December	1st to 10th	Day	27% 27% 29% 12% 4 1	300
	11th to 20th	Day	31% 18% 36% 12% 3 1	300
	21st to end	Day	36% 21% 29% 11% 3	330
January	1st to 10th	Night	28% 21% 31% 18% 3	1000
	11th to 20th	Night	29% 22% 32% 15% 2	1000
	21st to end	Night	25% 21% 34% 18% 2	980
February	1st to 10th	Night	29% 17% 35% 17% 2	800
	11th to 20th	Night	27% 25% 31% 16% 2	783
	21st to end	Night	30% 18% 36% 15% 1	629
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	8% 3 18% 32% 34% 5%	760
	21st to end	Night	17% 7% 22% 28% 23% 3	760
October	1st to 10th	Night	11% 7% 26% 30% 21% 5%	760
	11th to 20th	Night	18% 12% 29% 25% 14% 2	760
	21st to end	Night	22% 14% 32% 23% 8% 1	836
November	1st to 10th	Night	18% 13% 30% 26% 13% 1	780
	11th to 20th	Night	24% 17% 27% 23% 8%	800
	21st to end	Night	27% 17% 24% 25% 6%	800
December	1st to 10th	Night	27% 17% 33% 19% 5%	800
	11th to 20th	Night	28% 16% 30% 21% 5% 1	915
	21st to end	Night	35% 17% 29% 16% 3	1100

Page generated at 2025-02-18 03:26:30. Version ac07

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