Livonia
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Livonia clear sky chart from 2005-11-06 to 2024-04-10.

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	15% 10% 4 7% 6% 4 5% 5% 5% 7% 32%	82824
	Night	16% 10% 4 7% 6% 3 5% 5% 5% 6% 34%	85947
Transparency	Day	51% 6% 12% 19% 11% 1	82535
	Night	50% 6% 11% 20% 11% 1	85757
Seeing	Day	18% 13% 30% 22% 12% 5%	14554
	Night	20% 10% 29% 28% 11% 1	24590

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	16% 17% 6% 10% 7% 4 4 5% 4 6% 21%	2527
	11th to 20th	Day	16% 17% 7% 11% 9% 6% 8% 5% 5% 5% 12%	2530
	21st to end	Day	27% 19% 8% 10% 8% 3 4 3 3 3 12%	3097
February	1st to 10th	Day	15% 13% 5% 11% 9% 4 6% 5% 5% 5% 21%	1710
	11th to 20th	Day	14% 13% 5% 11% 9% 5% 5% 4 4 6% 24%	1794
	21st to end	Day	16% 14% 5% 10% 6% 3 5% 4 5% 7% 26%	1570
March	1st to 10th	Day	18% 15% 5% 9% 7% 3 4 3 4 5% 27%	3204
	11th to 20th	Day	13% 11% 5% 8% 7% 4 5% 4 5% 7% 32%	3480
	21st to end	Day	19% 12% 4 8% 7% 4 4 4 5% 5% 27%	3815
April	1st to 10th	Day	16% 12% 4 6% 5% 4 5% 5% 5% 7% 30%	2193
	11th to 20th	Day	17% 9% 3 6% 6% 3 5% 4 4 7% 34%	2280
	21st to end	Day	20% 9% 2 7% 5% 3 5% 4 4 7% 34%	2340
May	1st to 10th	Day	18% 9% 3 6% 5% 4 6% 4 5% 8% 32%	2340
	11th to 20th	Day	18% 9% 3 6% 6% 3 5% 5% 5% 7% 34%	2301
	21st to end	Day	12% 5% 2 6% 5% 3 5% 5% 6% 9% 41%	2531
June	1st to 10th	Day	11% 5% 3 6% 6% 4 6% 5% 5% 9% 41%	2497
	11th to 20th	Day	11% 5% 2 6% 5% 4 6% 5% 6% 9% 40%	2668
	21st to end	Day	9% 6% 3 5% 6% 3 6% 6% 7% 9% 38%	2520
July	1st to 10th	Day	7% 4 3 5% 6% 3 6% 6% 6% 9% 46%	2520
	11th to 20th	Day	9% 4 3 5% 6% 4 6% 6% 7% 10% 42%	2520
	21st to end	Day	8% 5% 2 5% 6% 3 6% 6% 7% 10% 41%	2578
August	1st to 10th	Day	7% 5% 2 6% 5% 4 5% 7% 8% 9% 41%	2327
	11th to 20th	Day	10% 4 3 6% 7% 4 7% 6% 7% 9% 37%	2303
	21st to end	Day	11% 5% 2 5% 5% 3 6% 6% 6% 10% 41%	2552
September	1st to 10th	Day	11% 6% 2 5% 6% 4 6% 7% 6% 9% 37%	2031
	11th to 20th	Day	9% 5% 2 5% 5% 3 5% 6% 7% 9% 44%	1980
	21st to end	Day	14% 6% 2 7% 5% 3 5% 5% 6% 9% 38%	1980
October	1st to 10th	Day	13% 7% 3 6% 6% 3 4 5% 6% 8% 40%	1931
	11th to 20th	Day	18% 9% 3 6% 6% 4 6% 5% 6% 7% 32%	1800
	21st to end	Day	20% 10% 3 7% 6% 4 4 4 5% 6% 31%	1841
November	1st to 10th	Day	11% 8% 3 7% 6% 3 5% 5% 6% 7% 38%	1672
	11th to 20th	Day	14% 11% 4 7% 6% 3 5% 4 6% 6% 31%	1710
	21st to end	Day	19% 12% 5% 7% 5% 4 5% 4 4 7% 28%	1624
December	1st to 10th	Day	15% 12% 8% 12% 8% 4 5% 4 5% 5% 22%	1520
	11th to 20th	Day	16% 15% 6% 9% 7% 3 5% 4 6% 6% 22%	1778
	21st to end	Day	27% 19% 8% 10% 6% 3 3 4 4 5% 10%	2760
January	1st to 10th	Night	17% 15% 6% 10% 7% 3 4 4 4 5% 25%	4428
	11th to 20th	Night	15% 18% 8% 12% 8% 4 6% 7% 5% 5% 15%	4440
	21st to end	Night	25% 17% 8% 9% 6% 3 3 3 3 4 17%	4556
February	1st to 10th	Night	17% 14% 5% 9% 9% 3 6% 5% 4 6% 24%	2470
	11th to 20th	Night	15% 11% 6% 9% 8% 4 5% 4 5% 6% 27%	2270
	21st to end	Night	19% 11% 4 7% 7% 4 4 4 5% 6% 29%	1884
March	1st to 10th	Night	16% 13% 4 7% 6% 2 3 3 5% 6% 34%	3648
	11th to 20th	Night	10% 8% 3 6% 5% 3 5% 5% 6% 8% 41%	3480
	21st to end	Night	17% 7% 3 7% 6% 4 5% 4 5% 6% 35%	3817
April	1st to 10th	Night	16% 9% 4 5% 5% 3 4 5% 5% 7% 36%	1991
	11th to 20th	Night	18% 7% 3 6% 5% 3 4 5% 6% 6% 37%	1629
	21st to end	Night	17% 8% 3 5% 5% 2 5% 6% 4 6% 39%	1620
May	1st to 10th	Night	17% 8% 4 7% 6% 4 5% 5% 5% 6% 34%	1620
	11th to 20th	Night	19% 5% 3 4 4 4 5% 5% 4 6% 40%	1592
	21st to end	Night	10% 5% 3 5% 5% 3 5% 4 6% 10% 45%	1744
June	1st to 10th	Night	12% 5% 2 4 4 3 5% 4 5% 10% 46%	1442
	11th to 20th	Night	10% 4 2 6% 5% 3 6% 4 6% 8% 46%	1274
	21st to end	Night	10% 4 2 5% 5% 3 5% 4 6% 8% 48%	1440
July	1st to 10th	Night	7% 4 2 4 4 3 5% 5% 5% 9% 53%	1440
	11th to 20th	Night	8% 3 2 4 4 3 4 5% 6% 8% 52%	1440
	21st to end	Night	5% 3 2 5% 4 3 5% 6% 6% 9% 51%	1739
August	1st to 10th	Night	7% 5% 2 5% 4 3 4 5% 6% 9% 49%	1611
	11th to 20th	Night	7% 5% 2 5% 5% 4 5% 4 5% 8% 50%	1598
	21st to end	Night	9% 4 2 3 4 3 4 4 6% 9% 51%	1801
September	1st to 10th	Night	11% 5% 2 5% 4 4 4 5% 5% 7% 47%	1910
	11th to 20th	Night	9% 5% 2 4 3 3 4 6% 5% 6% 53%	1980
	21st to end	Night	14% 6% 2 5% 5% 3 4 5% 5% 7% 45%	1980
October	1st to 10th	Night	14% 7% 3 6% 4 3 3 4 5% 7% 44%	2029
	11th to 20th	Night	18% 8% 3 6% 6% 4 5% 4 5% 5% 35%	2160
	21st to end	Night	21% 8% 3 7% 5% 3 4 5% 5% 6% 33%	2512
November	1st to 10th	Night	13% 7% 3 5% 5% 3 5% 5% 5% 6% 43%	2406
	11th to 20th	Night	17% 10% 4 6% 6% 3 5% 5% 6% 7% 31%	2470
	21st to end	Night	20% 13% 5% 7% 5% 3 4 4 5% 6% 30%	2550
December	1st to 10th	Night	18% 14% 7% 9% 7% 3 5% 5% 5% 6% 21%	2660
	11th to 20th	Night	15% 14% 6% 10% 6% 4 5% 5% 5% 6% 24%	3414
	21st to end	Night	29% 21% 7% 9% 5% 2 4 3 4 4 12%	4902

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% 7% 11% 12% 6%	2528
	11th to 20th	Day	73% 6% 9% 7% 4	2530
	21st to end	Day	78% 4 8% 6% 3 1	3097
February	1st to 10th	Day	63% 6% 9% 14% 7%	1710
	11th to 20th	Day	62% 5% 8% 16% 7% 1	1804
	21st to end	Day	59% 5% 11% 16% 7% 1	1570
March	1st to 10th	Day	60% 5% 11% 19% 5% 1	3204
	11th to 20th	Day	51% 5% 14% 20% 8% 2	3480
	21st to end	Day	57% 6% 12% 15% 9% 1	3815
April	1st to 10th	Day	52% 6% 11% 18% 12% 1	2193
	11th to 20th	Day	50% 5% 11% 19% 13% 2	2280
	21st to end	Day	51% 5% 13% 17% 13% 1	2340
May	1st to 10th	Day	51% 6% 10% 20% 11% 2	2340
	11th to 20th	Day	50% 6% 10% 18% 14% 2	2305
	21st to end	Day	39% 6% 14% 24% 15% 2	2531
June	1st to 10th	Day	40% 7% 11% 26% 14% 3	2497
	11th to 20th	Day	39% 7% 12% 22% 16% 3	2668
	21st to end	Day	39% 9% 12% 21% 17% 2	2520
July	1st to 10th	Day	35% 7% 10% 24% 20% 4	2451
	11th to 20th	Day	34% 7% 14% 24% 18% 2	2445
	21st to end	Day	36% 8% 13% 22% 18% 3	2435
August	1st to 10th	Day	35% 9% 14% 29% 13% 1	2314
	11th to 20th	Day	41% 9% 12% 24% 13% 2	2303
	21st to end	Day	37% 8% 11% 24% 18% 2	2552
September	1st to 10th	Day	41% 9% 14% 21% 14% 2	2031
	11th to 20th	Day	33% 8% 12% 33% 13% 1	1980
	21st to end	Day	41% 7% 13% 25% 13%	1980
October	1st to 10th	Day	41% 7% 11% 26% 14% 2	1931
	11th to 20th	Day	51% 5% 13% 20% 10%	1800
	21st to end	Day	54% 5% 12% 19% 10% 1	1841
November	1st to 10th	Day	44% 7% 12% 23% 13% 1	1672
	11th to 20th	Day	52% 5% 13% 19% 9% 1	1710
	21st to end	Day	56% 6% 12% 19% 7% 1	1624
December	1st to 10th	Day	64% 6% 12% 13% 5%	1520
	11th to 20th	Day	61% 6% 13% 15% 5%	1774
	21st to end	Day	78% 4 9% 6% 3	2760
January	1st to 10th	Night	61% 6% 12% 15% 6% 1	4428
	11th to 20th	Night	70% 6% 10% 9% 4	4440
	21st to end	Night	72% 5% 9% 11% 3	4556
February	1st to 10th	Night	62% 6% 11% 14% 6% 1	2470
	11th to 20th	Night	58% 5% 10% 18% 9% 1	2271
	21st to end	Night	56% 5% 12% 18% 8% 1	1884
March	1st to 10th	Night	51% 5% 12% 24% 7%	3648
	11th to 20th	Night	38% 7% 15% 20% 19% 1	3480
	21st to end	Night	48% 6% 11% 23% 11% 1	3817
April	1st to 10th	Night	48% 6% 10% 21% 14% 2	1991
	11th to 20th	Night	45% 6% 10% 19% 18% 2	1629
	21st to end	Night	46% 5% 11% 19% 15% 3	1620
May	1st to 10th	Night	50% 7% 10% 19% 13% 2	1620
	11th to 20th	Night	45% 6% 9% 20% 18% 3	1593
	21st to end	Night	35% 7% 13% 25% 17% 3	1745
June	1st to 10th	Night	35% 6% 11% 27% 17% 3	1442
	11th to 20th	Night	36% 7% 12% 26% 17% 2	1274
	21st to end	Night	33% 8% 10% 26% 21% 1	1440
July	1st to 10th	Night	29% 8% 9% 30% 20% 4	1400
	11th to 20th	Night	28% 7% 13% 30% 19% 2	1392
	21st to end	Night	28% 8% 16% 24% 20% 4	1642
August	1st to 10th	Night	30% 8% 13% 31% 16% 2	1600
	11th to 20th	Night	31% 8% 13% 32% 13% 3	1598
	21st to end	Night	31% 6% 13% 28% 20% 2	1801
September	1st to 10th	Night	34% 8% 12% 27% 17% 2	1910
	11th to 20th	Night	30% 6% 10% 32% 20% 2	1980
	21st to end	Night	39% 6% 11% 29% 14% 1	1980
October	1st to 10th	Night	40% 5% 10% 25% 19% 1	2029
	11th to 20th	Night	50% 5% 11% 20% 14% 1	2160
	21st to end	Night	52% 5% 11% 22% 9% 1	2512
November	1st to 10th	Night	41% 5% 12% 25% 15% 1	2406
	11th to 20th	Night	50% 5% 13% 21% 9% 1	2470
	21st to end	Night	56% 5% 13% 20% 7%	2550
December	1st to 10th	Night	64% 6% 10% 14% 6%	2660
	11th to 20th	Night	60% 6% 14% 13% 6% 1	3417
	21st to end	Night	76% 5% 10% 7% 2	4902

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	26% 21% 32% 15% 6%	270
	11th to 20th	Day	25% 18% 39% 15% 2 1	270
	21st to end	Day	28% 15% 35% 16% 4 1	297
February	1st to 10th	Day	24% 21% 37% 15% 3 1	270
	11th to 20th	Day	26% 18% 38% 16% 2	270
	21st to end	Day	25% 31% 33% 8% 2	225
March	1st to 10th	Day	29% 21% 30% 16% 4	315
	11th to 20th	Day	24% 14% 35% 20% 6% 1	460
	21st to end	Day	27% 17% 33% 17% 5% 1	506
April	1st to 10th	Day	21% 19% 33% 19% 7% 1	457
	11th to 20th	Day	26% 19% 28% 14% 8% 4	412
	21st to end	Day	27% 17% 28% 17% 8% 3	420
May	1st to 10th	Day	24% 16% 30% 20% 7% 4	423
	11th to 20th	Day	20% 11% 32% 19% 12% 5%	447
	21st to end	Day	14% 9% 23% 28% 18% 7%	485
June	1st to 10th	Day	12% 9% 33% 30% 12% 3	602
	11th to 20th	Day	15% 8% 31% 30% 13% 3	630
	21st to end	Day	12% 10% 32% 28% 14% 4	630
July	1st to 10th	Day	8% 5% 27% 28% 23% 9%	621
	11th to 20th	Day	10% 9% 29% 28% 17% 7%	618
	21st to end	Day	10% 5% 29% 26% 22% 8%	519
August	1st to 10th	Day	7% 3 27% 27% 22% 13%	446
	11th to 20th	Day	13% 5% 25% 28% 18% 12%	439
	21st to end	Day	10% 7% 22% 29% 23% 10%	495
September	1st to 10th	Day	13% 7% 24% 25% 21% 10%	450
	11th to 20th	Day	9% 5% 21% 26% 26% 12%	450
	21st to end	Day	16% 12% 24% 22% 18% 8%	450
October	1st to 10th	Day	15% 12% 27% 21% 17% 7%	450
	11th to 20th	Day	21% 19% 28% 23% 7% 2	450
	21st to end	Day	29% 15% 37% 14% 4 1	356
November	1st to 10th	Day	15% 22% 35% 18% 9% 1	270
	11th to 20th	Day	23% 24% 29% 17% 6% 1	270
	21st to end	Day	28% 19% 35% 13% 6%	229
December	1st to 10th	Day	24% 22% 34% 14% 6% 1	180
	11th to 20th	Day	27% 24% 36% 9% 3 1	180
	21st to end	Day	30% 24% 31% 12% 2	292
January	1st to 10th	Night	23% 17% 34% 20% 5% 1	950
	11th to 20th	Night	28% 14% 32% 22% 5% 1	950
	21st to end	Night	22% 14% 33% 26% 5%	847
February	1st to 10th	Night	26% 13% 35% 23% 3	760
	11th to 20th	Night	24% 15% 32% 26% 4	743
	21st to end	Night	26% 16% 36% 20% 2	628
March	1st to 10th	Night	21% 13% 33% 27% 6%	760
	11th to 20th	Night	19% 17% 35% 24% 4 1	760
	21st to end	Night	24% 12% 29% 27% 7% 1	836
April	1st to 10th	Night	21% 15% 32% 27% 4	661
	11th to 20th	Night	21% 11% 34% 25% 7% 1	533
	21st to end	Night	21% 10% 31% 30% 8%	540
May	1st to 10th	Night	21% 9% 29% 31% 9% 1	540
	11th to 20th	Night	21% 6% 27% 34% 12% 1	531
	21st to end	Night	11% 4 26% 38% 20% 2	584
June	1st to 10th	Night	13% 3 28% 42% 14%	518
	11th to 20th	Night	10% 5% 27% 46% 12%	374
	21st to end	Night	11% 4 26% 38% 20% 1	540
July	1st to 10th	Night	9% 2 20% 38% 26% 4	525
	11th to 20th	Night	10% 3 22% 41% 20% 4	522
	21st to end	Night	5% 3 21% 47% 22% 2	591
August	1st to 10th	Night	9% 3 18% 40% 26% 3	537
	11th to 20th	Night	11% 1 19% 35% 31% 3	534
	21st to end	Night	11% 3 18% 36% 30% 3	594
September	1st to 10th	Night	14% 6% 16% 34% 24% 4	650
	11th to 20th	Night	11% 4 19% 34% 29% 3	720
	21st to end	Night	16% 7% 23% 29% 22% 4	720
October	1st to 10th	Night	17% 9% 25% 29% 17% 3	720
	11th to 20th	Night	23% 14% 28% 24% 9% 1	720
	21st to end	Night	26% 13% 30% 26% 5%	792
November	1st to 10th	Night	18% 13% 30% 27% 12% 1	740
	11th to 20th	Night	23% 16% 32% 21% 7% 1	760
	21st to end	Night	28% 13% 33% 20% 6%	760
December	1st to 10th	Night	26% 15% 34% 18% 7%	760
	11th to 20th	Night	25% 15% 36% 20% 4	845
	21st to end	Night	33% 12% 32% 20% 3	1045

Page generated at 2024-04-07 09:28:12. Version ac07

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