Indian Lake State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Indian Lake State Park clear sky chart from 2005-11-06 to 2024-01-22.

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% 4 7% 6% 4 5% 5% 5% 7% 33%	75124
	Night	15% 10% 4 7% 6% 3 4 4 5% 6% 35%	74808
Transparency	Day	49% 7% 12% 19% 11% 2	74837
	Night	49% 6% 11% 20% 13% 2	74615
Seeing	Day	18% 10% 27% 23% 15% 7%	14323
	Night	19% 10% 28% 28% 14% 2	24206

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	17% 16% 7% 11% 9% 4 6% 3 4 5% 17%	1517
	11th to 20th	Day	16% 20% 9% 12% 8% 4 5% 4 3 5% 15%	1608
	21st to end	Day	15% 18% 9% 11% 8% 3 5% 5% 4 5% 17%	1791
February	1st to 10th	Day	19% 15% 6% 11% 9% 4 6% 4 4 4 19%	1647
	11th to 20th	Day	14% 12% 7% 14% 9% 5% 4 4 4 6% 21%	1748
	21st to end	Day	16% 14% 7% 10% 5% 3 4 3 4 6% 27%	1480
March	1st to 10th	Day	18% 12% 6% 8% 6% 4 4 4 4 6% 27%	1830
	11th to 20th	Day	17% 12% 6% 8% 6% 3 5% 4 5% 7% 27%	1980
	21st to end	Day	23% 12% 5% 9% 6% 3 3 3 4 5% 26%	2178
April	1st to 10th	Day	14% 12% 5% 8% 6% 4 5% 4 5% 6% 32%	2098
	11th to 20th	Day	18% 8% 3 6% 6% 3 4 4 6% 7% 35%	2229
	21st to end	Day	21% 8% 4 6% 5% 4 4 5% 5% 6% 32%	2340
May	1st to 10th	Day	19% 9% 4 7% 5% 4 5% 4 5% 6% 31%	2340
	11th to 20th	Day	19% 8% 3 6% 5% 3 5% 5% 6% 7% 32%	2301
	21st to end	Day	9% 6% 2 7% 6% 4 6% 7% 7% 9% 37%	2531
June	1st to 10th	Day	13% 6% 3 5% 5% 4 6% 6% 5% 8% 38%	2389
	11th to 20th	Day	11% 6% 2 6% 5% 3 5% 6% 6% 8% 41%	2520
	21st to end	Day	11% 4 3 6% 5% 4 6% 6% 8% 9% 38%	2520
July	1st to 10th	Day	11% 6% 3 5% 5% 3 6% 6% 8% 10% 39%	2520
	11th to 20th	Day	9% 5% 2 4 5% 4 5% 6% 7% 10% 45%	2471
	21st to end	Day	9% 4 2 6% 6% 4 5% 6% 6% 10% 41%	2547
August	1st to 10th	Day	8% 4 2 5% 5% 4 5% 6% 8% 11% 43%	2327
	11th to 20th	Day	10% 5% 2 6% 6% 4 6% 5% 8% 10% 39%	2303
	21st to end	Day	9% 5% 2 5% 5% 4 4 6% 7% 10% 43%	2471
September	1st to 10th	Day	12% 6% 2 5% 5% 2 5% 5% 6% 7% 46%	2035
	11th to 20th	Day	9% 5% 3 4 6% 3 5% 6% 6% 9% 44%	1980
	21st to end	Day	15% 6% 2 5% 4 3 4 4 4 7% 46%	1980
October	1st to 10th	Day	13% 7% 2 6% 5% 3 4 4 5% 7% 43%	1971
	11th to 20th	Day	17% 7% 3 5% 5% 2 5% 5% 5% 7% 39%	1800
	21st to end	Day	20% 9% 3 7% 5% 4 5% 5% 4 7% 30%	1850
November	1st to 10th	Day	11% 8% 4 4 4 3 3 3 4 6% 48%	1672
	11th to 20th	Day	16% 13% 5% 7% 5% 3 5% 3 5% 6% 34%	1710
	21st to end	Day	18% 14% 6% 9% 5% 3 4 3 4 5% 29%	1710
December	1st to 10th	Day	18% 17% 7% 10% 6% 4 5% 4 4 4 21%	1710
	11th to 20th	Day	14% 16% 7% 10% 7% 4 4 4 5% 6% 22%	2153
	21st to end	Day	21% 20% 11% 11% 8% 4 5% 3 3 4 10%	2867
January	1st to 10th	Night	17% 14% 7% 12% 8% 3 5% 4 4 5% 22%	2648
	11th to 20th	Night	18% 17% 7% 11% 7% 4 4 4 3 4 20%	2566
	21st to end	Night	16% 17% 7% 11% 7% 3 4 4 4 5% 21%	2599
February	1st to 10th	Night	21% 13% 6% 9% 7% 3 5% 4 4 5% 23%	2311
	11th to 20th	Night	15% 13% 4 10% 8% 3 5% 4 5% 7% 26%	2098
	21st to end	Night	19% 13% 5% 11% 6% 3 4 3 5% 5% 25%	1776
March	1st to 10th	Night	16% 9% 4 8% 6% 4 4 4 5% 5% 33%	2129
	11th to 20th	Night	14% 9% 4 6% 6% 3 4 5% 5% 7% 37%	1980
	21st to end	Night	21% 10% 4 7% 4 3 4 5% 5% 5% 32%	2178
April	1st to 10th	Night	15% 8% 3 6% 6% 2 5% 5% 6% 8% 37%	1877
	11th to 20th	Night	16% 8% 3 6% 5% 3 5% 5% 6% 8% 35%	1679
	21st to end	Night	16% 8% 3 8% 6% 3 4 4 5% 7% 35%	1620
May	1st to 10th	Night	19% 10% 3 7% 5% 2 5% 5% 6% 7% 31%	1620
	11th to 20th	Night	20% 7% 2 5% 5% 2 4 4 5% 8% 39%	1592
	21st to end	Night	7% 5% 2 6% 5% 4 4 6% 7% 12% 42%	1744
June	1st to 10th	Night	9% 6% 2 4 5% 3 5% 5% 6% 8% 48%	1566
	11th to 20th	Night	8% 6% 2 5% 4 3 4 6% 6% 8% 47%	1440
	21st to end	Night	9% 4 2 5% 5% 2 5% 6% 8% 8% 46%	1440
July	1st to 10th	Night	9% 4 2 6% 6% 3 4 3 7% 8% 47%	1440
	11th to 20th	Night	7% 4 3 5% 4 3 4 5% 7% 11% 49%	1484
	21st to end	Night	7% 5% 3 4 5% 2 4 5% 6% 8% 50%	1771
August	1st to 10th	Night	6% 4 1 5% 5% 4 5% 6% 7% 9% 47%	1611
	11th to 20th	Night	7% 6% 2 5% 5% 3 3 5% 7% 9% 48%	1598
	21st to end	Night	6% 4 1 5% 5% 3 5% 6% 6% 8% 51%	1880
September	1st to 10th	Night	11% 6% 2 5% 4 3 3 4 5% 7% 50%	1905
	11th to 20th	Night	10% 5% 2 5% 3 2 3 4 5% 7% 54%	1980
	21st to end	Night	11% 5% 3 5% 5% 3 5% 5% 5% 6% 48%	1980
October	1st to 10th	Night	11% 4 2 5% 5% 3 3 5% 5% 7% 51%	1988
	11th to 20th	Night	17% 9% 3 5% 5% 3 4 4 5% 6% 38%	2160
	21st to end	Night	21% 8% 3 5% 6% 3 4 5% 5% 5% 36%	2502
November	1st to 10th	Night	13% 9% 2 6% 4 3 3 5% 5% 6% 44%	2406
	11th to 20th	Night	18% 10% 4 7% 5% 2 4 3 4 7% 36%	2470
	21st to end	Night	19% 13% 5% 8% 5% 4 4 5% 5% 5% 27%	2470
December	1st to 10th	Night	18% 16% 6% 9% 6% 3 4 4 4 6% 23%	2470
	11th to 20th	Night	17% 14% 8% 8% 6% 4 4 4 4 5% 25%	3042
	21st to end	Night	22% 20% 8% 10% 6% 3 4 3 4 5% 15%	4788

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	70% 4 7% 14% 6%	1518
	11th to 20th	Day	72% 5% 10% 9% 4	1608
	21st to end	Day	69% 5% 9% 11% 5% 1	1791
February	1st to 10th	Day	69% 4 9% 11% 6%	1647
	11th to 20th	Day	65% 5% 9% 13% 7%	1758
	21st to end	Day	59% 4 11% 16% 7% 2	1480
March	1st to 10th	Day	58% 6% 10% 19% 7% 1	1830
	11th to 20th	Day	56% 5% 11% 16% 10% 2	1980
	21st to end	Day	61% 5% 10% 19% 5% 1	2178
April	1st to 10th	Day	52% 6% 12% 18% 11% 1	2098
	11th to 20th	Day	48% 6% 11% 19% 12% 2	2229
	21st to end	Day	51% 7% 12% 19% 10% 2	2340
May	1st to 10th	Day	53% 7% 12% 18% 9% 1	2340
	11th to 20th	Day	50% 8% 12% 19% 10% 1	2305
	21st to end	Day	39% 10% 16% 23% 10% 1	2531
June	1st to 10th	Day	42% 7% 11% 24% 13% 2	2389
	11th to 20th	Day	38% 9% 14% 23% 15% 2	2520
	21st to end	Day	38% 9% 16% 19% 14% 4	2520
July	1st to 10th	Day	39% 8% 14% 20% 15% 3	2451
	11th to 20th	Day	33% 8% 15% 26% 17% 1	2396
	21st to end	Day	35% 8% 17% 25% 13% 3	2405
August	1st to 10th	Day	32% 10% 14% 27% 15% 2	2314
	11th to 20th	Day	37% 9% 13% 27% 12% 1	2303
	21st to end	Day	34% 9% 15% 22% 16% 5%	2471
September	1st to 10th	Day	36% 8% 13% 22% 18% 3	2035
	11th to 20th	Day	35% 7% 12% 24% 20% 2	1980
	21st to end	Day	39% 5% 10% 25% 20% 1	1980
October	1st to 10th	Day	40% 6% 10% 24% 17% 2	1971
	11th to 20th	Day	43% 5% 12% 22% 16% 2	1800
	21st to end	Day	55% 5% 12% 18% 10% 1	1850
November	1st to 10th	Day	38% 5% 12% 24% 18% 2	1672
	11th to 20th	Day	53% 4 10% 20% 11% 2	1710
	21st to end	Day	58% 4 10% 18% 8% 1	1710
December	1st to 10th	Day	66% 5% 10% 14% 4	1710
	11th to 20th	Day	61% 5% 11% 15% 7%	2150
	21st to end	Day	79% 4 6% 6% 4	2867
January	1st to 10th	Night	66% 4 7% 15% 7%	2648
	11th to 20th	Night	69% 4 9% 13% 5%	2566
	21st to end	Night	65% 5% 9% 13% 7% 1	2599
February	1st to 10th	Night	64% 5% 10% 14% 7% 1	2311
	11th to 20th	Night	58% 5% 12% 15% 9% 1	2099
	21st to end	Night	62% 4 8% 15% 9% 2	1776
March	1st to 10th	Night	52% 5% 10% 20% 11% 1	2129
	11th to 20th	Night	47% 5% 10% 22% 12% 3	1980
	21st to end	Night	52% 6% 8% 22% 10% 1	2178
April	1st to 10th	Night	44% 7% 13% 21% 13% 2	1877
	11th to 20th	Night	45% 7% 11% 17% 17% 3	1679
	21st to end	Night	48% 5% 12% 20% 13% 2	1620
May	1st to 10th	Night	51% 7% 12% 17% 9% 3	1620
	11th to 20th	Night	44% 6% 13% 19% 15% 2	1593
	21st to end	Night	33% 10% 16% 25% 13% 3	1745
June	1st to 10th	Night	34% 7% 14% 22% 21% 2	1566
	11th to 20th	Night	32% 9% 15% 26% 15% 3	1440
	21st to end	Night	32% 9% 16% 23% 16% 3	1440
July	1st to 10th	Night	35% 8% 14% 22% 18% 4	1400
	11th to 20th	Night	29% 7% 15% 29% 18% 1	1436
	21st to end	Night	30% 7% 16% 28% 15% 4	1672
August	1st to 10th	Night	31% 8% 16% 27% 17% 1	1600
	11th to 20th	Night	32% 8% 13% 27% 20% 1	1598
	21st to end	Night	29% 8% 16% 22% 21% 5%	1880
September	1st to 10th	Night	33% 6% 13% 25% 17% 5%	1905
	11th to 20th	Night	30% 6% 11% 27% 25% 3	1980
	21st to end	Night	36% 6% 10% 23% 22% 3	1980
October	1st to 10th	Night	33% 6% 12% 25% 23% 1	1988
	11th to 20th	Night	45% 6% 8% 24% 15% 1	2160
	21st to end	Night	49% 6% 9% 21% 13% 2	2502
November	1st to 10th	Night	40% 5% 10% 23% 19% 2	2406
	11th to 20th	Night	50% 4 9% 21% 14% 3	2470
	21st to end	Night	57% 6% 10% 18% 9% 1	2470
December	1st to 10th	Night	63% 5% 9% 16% 7%	2470
	11th to 20th	Night	60% 6% 11% 17% 6%	3044
	21st to end	Night	73% 5% 9% 10% 3	4788

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	24% 21% 34% 18% 3 1	270
	11th to 20th	Day	23% 23% 38% 11% 5%	270
	21st to end	Day	25% 22% 32% 16% 4	267
February	1st to 10th	Day	34% 18% 33% 13% 2	240
	11th to 20th	Day	23% 23% 38% 13% 3	240
	21st to end	Day	23% 24% 45% 7% 2	198
March	1st to 10th	Day	25% 20% 36% 17% 2	270
	11th to 20th	Day	25% 13% 36% 18% 6% 1	420
	21st to end	Day	29% 16% 32% 18% 5% 1	462
April	1st to 10th	Day	22% 13% 32% 23% 7% 3	420
	11th to 20th	Day	20% 19% 26% 20% 11% 5%	412
	21st to end	Day	25% 12% 33% 19% 9% 2	420
May	1st to 10th	Day	26% 11% 29% 22% 8% 3	423
	11th to 20th	Day	22% 8% 28% 23% 13% 6%	447
	21st to end	Day	11% 6% 25% 26% 21% 11%	485
June	1st to 10th	Day	14% 6% 26% 27% 20% 6%	499
	11th to 20th	Day	13% 6% 25% 27% 22% 7%	630
	21st to end	Day	13% 7% 26% 28% 20% 5%	630
July	1st to 10th	Day	12% 2 17% 30% 20% 19%	621
	11th to 20th	Day	8% 3 21% 30% 22% 16%	569
	21st to end	Day	11% 1 19% 25% 28% 16%	488
August	1st to 10th	Day	11% 4 12% 26% 27% 20%	446
	11th to 20th	Day	13% 4 16% 28% 26% 13%	439
	21st to end	Day	9% 3 17% 26% 28% 17%	495
September	1st to 10th	Day	15% 4 15% 27% 28% 12%	450
	11th to 20th	Day	9% 4 14% 27% 27% 19%	450
	21st to end	Day	17% 9% 20% 25% 18% 10%	450
October	1st to 10th	Day	13% 5% 24% 28% 21% 8%	450
	11th to 20th	Day	18% 14% 32% 22% 12% 1	450
	21st to end	Day	25% 13% 37% 21% 4 1	365
November	1st to 10th	Day	15% 14% 34% 24% 9% 4	270
	11th to 20th	Day	25% 17% 29% 19% 10%	270
	21st to end	Day	29% 14% 39% 17% 2	270
December	1st to 10th	Day	23% 20% 36% 15% 6%	270
	11th to 20th	Day	21% 17% 41% 17% 3	270
	21st to end	Day	29% 20% 34% 14% 2	297
January	1st to 10th	Night	22% 18% 35% 21% 4	950
	11th to 20th	Night	27% 17% 35% 16% 4	856
	21st to end	Night	23% 15% 38% 21% 4	800
February	1st to 10th	Night	28% 11% 37% 22% 2	720
	11th to 20th	Night	23% 16% 36% 23% 2	703
	21st to end	Night	24% 16% 38% 18% 3	592
March	1st to 10th	Night	22% 13% 34% 24% 6% 1	720
	11th to 20th	Night	19% 15% 34% 25% 6% 1	720
	21st to end	Night	26% 11% 30% 25% 7% 1	792
April	1st to 10th	Night	19% 11% 37% 27% 5% 1	617
	11th to 20th	Night	20% 10% 34% 24% 11% 1	533
	21st to end	Night	18% 9% 36% 26% 10% 1	540
May	1st to 10th	Night	22% 8% 29% 29% 10% 1	540
	11th to 20th	Night	23% 5% 26% 30% 15% 1	531
	21st to end	Night	10% 2 25% 37% 24% 3	584
June	1st to 10th	Night	10% 3 25% 41% 20% 1	540
	11th to 20th	Night	12% 3 21% 40% 24% 1	540
	21st to end	Night	10% 4 20% 40% 25% 1	540
July	1st to 10th	Night	10% 3 12% 41% 28% 6%	525
	11th to 20th	Night	8% 4 14% 39% 31% 4	522
	21st to end	Night	8% 3 14% 40% 34% 2	591
August	1st to 10th	Night	9% 1 12% 40% 33% 5%	537
	11th to 20th	Night	9% 2 10% 40% 33% 5%	534
	21st to end	Night	8% 2 13% 36% 35% 6%	594
September	1st to 10th	Night	14% 3 14% 34% 30% 5%	645
	11th to 20th	Night	11% 4 13% 33% 33% 6%	720
	21st to end	Night	13% 5% 22% 34% 22% 3	720
October	1st to 10th	Night	13% 5% 25% 34% 19% 4	720
	11th to 20th	Night	22% 11% 27% 29% 9% 1	720
	21st to end	Night	25% 11% 33% 23% 7%	792
November	1st to 10th	Night	17% 10% 34% 25% 13% 1	740
	11th to 20th	Night	22% 18% 29% 23% 8% 1	760
	21st to end	Night	25% 13% 31% 25% 6% 1	760
December	1st to 10th	Night	25% 15% 34% 22% 4	760
	11th to 20th	Night	25% 13% 36% 21% 5% 1	760
	21st to end	Night	29% 16% 33% 20% 3	988

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