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 2025-01-22.

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% 10% 4 8% 5% 4 5% 4 6% 7% 33%	105406
	Night	15% 11% 4 8% 5% 4 4 3 5% 6% 34%	103926
Transparency	Day	48% 6% 12% 21% 12% 1	109062
	Night	48% 6% 11% 21% 13% 2	108396
Seeing	Day	18% 11% 27% 23% 14% 7%	15690
	Night	19% 10% 28% 28% 13% 2	25537

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% 18% 10% 14% 6% 5% 4 2 4 5% 18%	2607
	11th to 20th	Day	14% 21% 7% 13% 5% 5% 9% 4 3 4 15%	2751
	21st to end	Day	25% 21% 9% 13% 5% 4 4 3 3 3 10%	3133
February	1st to 10th	Day	18% 16% 6% 12% 8% 5% 4 3 4 4 20%	1738
	11th to 20th	Day	14% 13% 6% 15% 8% 5% 5% 3 4 5% 23%	1848
	21st to end	Day	16% 15% 6% 11% 5% 4 3 3 4 7% 27%	1570
March	1st to 10th	Day	21% 20% 6% 9% 4 5% 3 3 4 5% 21%	3178
	11th to 20th	Day	13% 11% 4 7% 4 5% 5% 4 6% 7% 36%	3480
	21st to end	Day	20% 12% 5% 10% 5% 4 4 3 5% 5% 28%	3815
April	1st to 10th	Day	14% 13% 4 9% 6% 4 5% 3 5% 6% 31%	2215
	11th to 20th	Day	17% 9% 3 7% 5% 4 4 4 5% 7% 36%	2355
	21st to end	Day	20% 8% 4 7% 5% 5% 4 4 5% 7% 32%	2470
May	1st to 10th	Day	20% 9% 4 8% 4 4 4 3 6% 7% 30%	4082
	11th to 20th	Day	19% 8% 2 7% 4 4 4 3 6% 7% 36%	4081
	21st to end	Day	10% 6% 2 7% 5% 5% 5% 5% 7% 9% 38%	4476
June	1st to 10th	Day	12% 7% 3 6% 5% 5% 6% 4 5% 9% 38%	2522
	11th to 20th	Day	10% 6% 2 7% 4 4 5% 4 6% 9% 42%	2660
	21st to end	Day	11% 5% 2 6% 5% 5% 6% 5% 8% 9% 38%	2660
July	1st to 10th	Day	11% 7% 3 7% 5% 5% 5% 4 7% 10% 36%	4440
	11th to 20th	Day	8% 5% 2 4 4 4 5% 5% 7% 10% 46%	4349
	21st to end	Day	8% 6% 2 8% 5% 5% 6% 5% 7% 9% 39%	4466
August	1st to 10th	Day	8% 5% 2 6% 4 4 4 4 7% 11% 43%	4104
	11th to 20th	Day	9% 5% 2 6% 5% 5% 5% 4 9% 11% 40%	4044
	21st to end	Day	7% 5% 2 6% 4 5% 4 5% 7% 10% 46%	4345
September	1st to 10th	Day	11% 6% 2 5% 4 3 5% 3 6% 7% 48%	2148
	11th to 20th	Day	9% 5% 3 5% 5% 4 6% 4 6% 9% 45%	2090
	21st to end	Day	16% 7% 2 6% 3 4 4 3 4 6% 44%	2090
October	1st to 10th	Day	13% 7% 2 6% 4 4 4 3 5% 6% 45%	2080
	11th to 20th	Day	16% 7% 3 5% 4 4 5% 4 5% 6% 41%	1900
	21st to end	Day	19% 10% 3 8% 4 5% 5% 4 5% 7% 31%	1952
November	1st to 10th	Day	11% 9% 3 5% 4 4 3 2 5% 6% 48%	1762
	11th to 20th	Day	15% 14% 4 8% 5% 4 4 3 5% 5% 33%	1800
	21st to end	Day	18% 16% 5% 10% 5% 4 3 3 4 5% 28%	1800
December	1st to 10th	Day	16% 16% 5% 10% 6% 5% 4 3 4 4 28%	2930
	11th to 20th	Day	17% 17% 7% 12% 5% 4 4 3 4 5% 20%	3373
	21st to end	Day	23% 20% 9% 12% 6% 5% 4 2 3 4 12%	4092
January	1st to 10th	Night	16% 19% 8% 14% 6% 4 4 3 4 4 19%	4568
	11th to 20th	Night	14% 19% 8% 16% 6% 5% 5% 5% 4 3 14%	4416
	21st to end	Night	26% 20% 8% 10% 5% 4 3 3 3 3 14%	4546
February	1st to 10th	Night	20% 14% 5% 10% 6% 4 4 3 4 5% 25%	2440
	11th to 20th	Night	14% 13% 4 11% 6% 4 4 3 5% 7% 27%	2218
	21st to end	Night	19% 14% 5% 12% 5% 4 3 3 5% 5% 25%	1884
March	1st to 10th	Night	19% 14% 4 7% 4 4 3 3 4 5% 34%	3674
	11th to 20th	Night	13% 8% 3 6% 5% 4 4 3 5% 7% 42%	3480
	21st to end	Night	19% 10% 3 7% 4 4 4 4 4 4 36%	3817
April	1st to 10th	Night	16% 9% 3 7% 5% 3 4 4 6% 7% 36%	1981
	11th to 20th	Night	17% 8% 2 7% 5% 4 5% 3 6% 7% 35%	1773
	21st to end	Night	16% 9% 3 8% 5% 4 5% 3 6% 7% 35%	1710
May	1st to 10th	Night	20% 12% 3 8% 5% 3 5% 4 6% 6% 29%	2813
	11th to 20th	Night	19% 7% 2 6% 4 3 4 3 5% 8% 39%	2812
	21st to end	Night	9% 5% 2 6% 5% 4 5% 4 7% 10% 45%	3079
June	1st to 10th	Night	9% 6% 2 5% 5% 5% 4 4 6% 8% 47%	1652
	11th to 20th	Night	8% 6% 2 6% 4 4 4 5% 6% 9% 47%	1520
	21st to end	Night	8% 5% 2 6% 4 3 6% 4 8% 8% 46%	1520
July	1st to 10th	Night	10% 5% 2 7% 4 4 4 3 7% 8% 47%	2530
	11th to 20th	Night	7% 4 2 4 4 4 4 4 7% 10% 51%	2613
	21st to end	Night	9% 7% 3 6% 5% 4 5% 4 6% 8% 44%	3087
August	1st to 10th	Night	10% 8% 2 7% 4 5% 5% 4 7% 9% 40%	2825
	11th to 20th	Night	7% 7% 3 7% 4 4 4 4 6% 8% 45%	2785
	21st to end	Night	4 4 2 7% 4 5% 5% 5% 7% 8% 49%	3306
September	1st to 10th	Night	10% 6% 2 5% 3 3 3 3 5% 7% 52%	2011
	11th to 20th	Night	9% 5% 2 5% 3 2 3 3 5% 7% 55%	2090
	21st to end	Night	12% 7% 3 6% 4 4 5% 4 5% 5% 46%	2090
October	1st to 10th	Night	10% 4 2 5% 4 4 4 4 5% 7% 52%	2099
	11th to 20th	Night	16% 9% 2 7% 4 4 4 3 5% 7% 40%	2280
	21st to end	Night	20% 8% 2 6% 5% 4 4 4 5% 6% 37%	2641
November	1st to 10th	Night	12% 9% 2 7% 3 3 4 3 5% 6% 44%	2536
	11th to 20th	Night	17% 11% 3 8% 4 3 3 3 4 6% 35%	2600
	21st to end	Night	19% 15% 5% 9% 5% 5% 4 4 5% 5% 26%	2600
December	1st to 10th	Night	14% 13% 5% 10% 5% 5% 5% 4 5% 7% 27%	4250
	11th to 20th	Night	18% 17% 8% 12% 4 4 4 3 4 5% 21%	4822
	21st to end	Night	23% 21% 7% 11% 5% 4 4 3 4 5% 14%	6858

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	69% 5% 7% 12% 7%	2608
	11th to 20th	Day	74% 3 8% 9% 6%	2751
	21st to end	Day	80% 4 7% 7% 3	3133
February	1st to 10th	Day	67% 4 10% 11% 8%	1738
	11th to 20th	Day	64% 4 9% 14% 8%	1858
	21st to end	Day	58% 4 12% 16% 7% 2	1570
March	1st to 10th	Day	65% 6% 8% 16% 5%	3178
	11th to 20th	Day	46% 7% 10% 26% 10% 1	3480
	21st to end	Day	56% 7% 12% 19% 6%	3815
April	1st to 10th	Day	53% 6% 12% 17% 11%	2215
	11th to 20th	Day	47% 6% 11% 21% 12% 2	2355
	21st to end	Day	50% 7% 12% 19% 10% 2	2470
May	1st to 10th	Day	52% 7% 11% 20% 8% 1	4120
	11th to 20th	Day	45% 7% 14% 24% 8% 1	4085
	21st to end	Day	37% 12% 14% 20% 15% 2	4489
June	1st to 10th	Day	42% 7% 11% 24% 13% 2	2522
	11th to 20th	Day	37% 9% 14% 23% 16% 2	2660
	21st to end	Day	38% 9% 15% 18% 15% 4	2660
July	1st to 10th	Day	43% 6% 11% 21% 16% 2	4371
	11th to 20th	Day	31% 7% 14% 27% 20% 1	4274
	21st to end	Day	38% 8% 15% 20% 17% 3	4324
August	1st to 10th	Day	33% 9% 16% 26% 15% 1	4091
	11th to 20th	Day	34% 8% 12% 32% 14% 1	4083
	21st to end	Day	32% 7% 15% 31% 13% 3	4344
September	1st to 10th	Day	34% 7% 13% 22% 20% 3	2148
	11th to 20th	Day	34% 7% 11% 24% 21% 3	2090
	21st to end	Day	41% 5% 10% 24% 19% 1	2090
October	1st to 10th	Day	26% 5% 11% 32% 24% 1	3457
	11th to 20th	Day	35% 5% 10% 26% 23% 1	3140
	21st to end	Day	42% 4 11% 22% 20% 1	3189
November	1st to 10th	Day	38% 5% 12% 25% 18% 2	1762
	11th to 20th	Day	53% 4 10% 20% 11% 2	1800
	21st to end	Day	59% 4 10% 18% 8% 1	1800
December	1st to 10th	Day	60% 4 13% 18% 4	2930
	11th to 20th	Day	66% 4 12% 13% 5%	3370
	21st to end	Day	76% 4 7% 9% 4	4092
January	1st to 10th	Night	68% 5% 8% 13% 6%	4568
	11th to 20th	Night	74% 5% 8% 10% 3	4416
	21st to end	Night	75% 4 7% 9% 4	4546
February	1st to 10th	Night	62% 5% 10% 14% 8% 1	2440
	11th to 20th	Night	57% 5% 11% 16% 10% 1	2219
	21st to end	Night	61% 4 8% 15% 10% 2	1884
March	1st to 10th	Night	53% 5% 8% 23% 9% 1	3674
	11th to 20th	Night	39% 7% 12% 27% 13% 2	3480
	21st to end	Night	47% 7% 10% 25% 9% 1	3817
April	1st to 10th	Night	45% 7% 13% 20% 13% 1	1981
	11th to 20th	Night	45% 7% 11% 17% 16% 3	1773
	21st to end	Night	48% 6% 12% 19% 13% 2	1710
May	1st to 10th	Night	53% 8% 11% 18% 8% 2	2840
	11th to 20th	Night	42% 8% 15% 24% 10% 1	2813
	21st to end	Night	31% 10% 15% 26% 16% 2	3087
June	1st to 10th	Night	34% 7% 13% 22% 21% 2	1652
	11th to 20th	Night	31% 9% 15% 26% 16% 3	1520
	21st to end	Night	32% 9% 16% 24% 16% 3	1520
July	1st to 10th	Night	36% 7% 11% 26% 15% 5%	2490
	11th to 20th	Night	27% 6% 16% 29% 21% 1	2565
	21st to end	Night	37% 7% 15% 20% 17% 5%	2988
August	1st to 10th	Night	39% 7% 15% 24% 14% 1	2814
	11th to 20th	Night	36% 7% 10% 29% 18%	2812
	21st to end	Night	30% 8% 15% 28% 18% 3	3306
September	1st to 10th	Night	32% 6% 12% 26% 18% 5%	2011
	11th to 20th	Night	29% 6% 10% 26% 26% 4	2090
	21st to end	Night	39% 6% 10% 22% 21% 2	2090
October	1st to 10th	Night	23% 4 8% 31% 33% 2	3502
	11th to 20th	Night	33% 4 10% 26% 24% 2	3779
	21st to end	Night	36% 4 8% 28% 21% 4	4341
November	1st to 10th	Night	40% 5% 10% 23% 19% 2	2536
	11th to 20th	Night	50% 4 9% 21% 14% 3	2600
	21st to end	Night	58% 6% 10% 18% 8% 1	2600
December	1st to 10th	Night	58% 4 12% 21% 5%	4250
	11th to 20th	Night	66% 5% 12% 12% 6%	4824
	21st to end	Night	73% 4 9% 11% 3	6858

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% 2 1	300
	11th to 20th	Day	22% 24% 38% 11% 4	300
	21st to end	Day	29% 21% 32% 14% 4	300
February	1st to 10th	Day	30% 18% 33% 15% 3	270
	11th to 20th	Day	23% 22% 37% 16% 3	270
	21st to end	Day	23% 24% 44% 8% 2	225
March	1st to 10th	Day	26% 19% 35% 17% 2	302
	11th to 20th	Day	25% 15% 35% 18% 5% 1	460
	21st to end	Day	28% 16% 32% 18% 5% 1	506
April	1st to 10th	Day	21% 16% 32% 22% 7% 2	460
	11th to 20th	Day	19% 21% 26% 20% 10% 4	452
	21st to end	Day	24% 12% 34% 19% 9% 2	460
May	1st to 10th	Day	25% 12% 30% 22% 8% 3	463
	11th to 20th	Day	21% 8% 27% 23% 13% 7%	487
	21st to end	Day	11% 7% 27% 26% 21% 10%	529
June	1st to 10th	Day	13% 8% 27% 27% 19% 7%	542
	11th to 20th	Day	13% 6% 25% 29% 21% 7%	680
	21st to end	Day	12% 7% 28% 29% 19% 5%	680
July	1st to 10th	Day	13% 3 18% 30% 19% 18%	671
	11th to 20th	Day	8% 3 23% 29% 22% 15%	616
	21st to end	Day	11% 2 19% 27% 27% 15%	532
August	1st to 10th	Day	10% 4 14% 27% 27% 19%	486
	11th to 20th	Day	13% 4 16% 29% 25% 12%	479
	21st to end	Day	8% 3 16% 26% 30% 16%	539
September	1st to 10th	Day	14% 4 15% 28% 28% 11%	490
	11th to 20th	Day	9% 4 13% 27% 29% 19%	490
	21st to end	Day	20% 9% 20% 24% 17% 9%	490
October	1st to 10th	Day	12% 6% 23% 29% 21% 8%	490
	11th to 20th	Day	18% 14% 31% 22% 12% 3	490
	21st to end	Day	23% 13% 37% 21% 5% 1	401
November	1st to 10th	Day	15% 14% 34% 24% 9% 4	300
	11th to 20th	Day	25% 17% 30% 18% 9%	300
	21st to end	Day	30% 15% 38% 16% 2	300
December	1st to 10th	Day	23% 19% 36% 15% 6%	300
	11th to 20th	Day	23% 18% 41% 15% 3	300
	21st to end	Day	29% 20% 34% 15% 2	330
January	1st to 10th	Night	22% 18% 36% 20% 4	1000
	11th to 20th	Night	26% 18% 36% 16% 4	901
	21st to end	Night	24% 15% 37% 20% 3	841
February	1st to 10th	Night	26% 12% 37% 23% 2	760
	11th to 20th	Night	22% 16% 36% 23% 2	743
	21st to end	Night	24% 16% 38% 18% 3	628
March	1st to 10th	Night	22% 13% 33% 24% 6% 1	760
	11th to 20th	Night	19% 16% 35% 25% 6% 1	760
	21st to end	Night	26% 12% 30% 26% 7%	836
April	1st to 10th	Night	19% 12% 37% 26% 5% 1	651
	11th to 20th	Night	20% 10% 34% 24% 10% 1	563
	21st to end	Night	18% 9% 37% 26% 9% 1	570
May	1st to 10th	Night	22% 8% 29% 30% 10% 1	570
	11th to 20th	Night	22% 5% 27% 31% 15% 1	561
	21st to end	Night	10% 2 25% 37% 23% 3	617
June	1st to 10th	Night	11% 3 25% 41% 20% 1	570
	11th to 20th	Night	11% 3 21% 41% 23% 1	570
	21st to end	Night	10% 4 21% 40% 24% 1	570
July	1st to 10th	Night	11% 3 13% 41% 27% 6%	555
	11th to 20th	Night	8% 3 15% 40% 30% 4	552
	21st to end	Night	8% 3 13% 41% 33% 2	624
August	1st to 10th	Night	9% 2 12% 40% 33% 4	567
	11th to 20th	Night	9% 3 11% 41% 31% 5%	564
	21st to end	Night	7% 2 13% 37% 35% 6%	627
September	1st to 10th	Night	13% 3 14% 35% 30% 5%	681
	11th to 20th	Night	11% 4 13% 35% 33% 6%	760
	21st to end	Night	15% 6% 22% 33% 21% 3	760
October	1st to 10th	Night	13% 4 25% 35% 19% 4	760
	11th to 20th	Night	21% 11% 27% 29% 11% 2	760
	21st to end	Night	24% 11% 34% 23% 8%	836
November	1st to 10th	Night	17% 10% 34% 26% 13% 1	780
	11th to 20th	Night	22% 17% 29% 23% 7% 1	800
	21st to end	Night	25% 13% 31% 24% 6% 1	800
December	1st to 10th	Night	24% 15% 35% 21% 4	800
	11th to 20th	Night	25% 13% 36% 20% 5% 1	800
	21st to end	Night	30% 16% 32% 19% 3	1040

Page generated at 2025-01-19 03:06:45. Version ac07

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