Terre Haute
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Terre Haute clear sky chart from 2005-11-06 to 2026-06-01.

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 7% 5% 4 4 4 6% 7% 37%	131787
	Night	15% 9% 3 7% 4 4 4 3 5% 7% 39%	131583
Transparency	Day	44% 5% 11% 24% 14% 2	135362
	Night	45% 4 10% 23% 15% 2	136070
Seeing	Day	17% 10% 26% 24% 17% 6%	17693
	Night	18% 9% 28% 30% 14% 1	27573

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% 12% 6% 11% 6% 4 4 3 5% 7% 29%	4691
	11th to 20th	Day	10% 12% 6% 14% 8% 6% 5% 4 4 5% 25%	4710
	21st to end	Day	19% 14% 5% 11% 6% 4 3 3 4 4 25%	5452
February	1st to 10th	Day	17% 13% 5% 9% 5% 3 3 3 5% 6% 31%	2082
	11th to 20th	Day	17% 10% 4 11% 5% 5% 4 3 4 6% 31%	2048
	21st to end	Day	16% 12% 3 8% 5% 4 4 4 3 5% 35%	1730
March	1st to 10th	Day	19% 14% 4 8% 4 3 3 2 3 3 38%	4580
	11th to 20th	Day	11% 10% 3 5% 4 3 4 3 6% 8% 43%	4761
	21st to end	Day	17% 10% 3 8% 5% 5% 5% 4 6% 7% 32%	6067
April	1st to 10th	Day	17% 11% 3 6% 4 4 4 3 5% 7% 36%	2520
	11th to 20th	Day	16% 8% 2 6% 4 5% 4 4 5% 5% 39%	2494
	21st to end	Day	19% 7% 3 7% 4 4 4 3 5% 7% 37%	2612
May	1st to 10th	Day	19% 8% 3 8% 5% 5% 5% 4 6% 8% 29%	5992
	11th to 20th	Day	18% 7% 2 6% 5% 4 4 4 5% 7% 37%	5991
	21st to end	Day	13% 7% 3 8% 5% 6% 5% 4 7% 9% 34%	6950
June	1st to 10th	Day	11% 5% 2 6% 4 3 4 4 6% 9% 44%	2801
	11th to 20th	Day	9% 5% 2 5% 4 4 5% 5% 6% 9% 46%	2800
	21st to end	Day	10% 5% 2 6% 5% 5% 5% 4 7% 9% 43%	2800
July	1st to 10th	Day	11% 5% 2 6% 4 4 4 4 7% 11% 44%	6360
	11th to 20th	Day	8% 6% 2 8% 5% 6% 6% 5% 8% 10% 36%	6360
	21st to end	Day	11% 6% 2 7% 5% 5% 6% 5% 8% 10% 34%	6924
August	1st to 10th	Day	7% 4 2 5% 4 4 4 4 6% 9% 51%	4181
	11th to 20th	Day	9% 5% 2 6% 5% 5% 5% 5% 8% 10% 41%	3849
	21st to end	Day	5% 5% 2 5% 4 4 4 4 6% 10% 53%	4312
September	1st to 10th	Day	10% 5% 2 5% 4 4 5% 4 5% 7% 48%	2400
	11th to 20th	Day	9% 4 2 5% 4 4 5% 5% 7% 8% 49%	2226
	21st to end	Day	12% 4 2 6% 4 4 4 3 5% 7% 50%	2200
October	1st to 10th	Day	12% 3 2 5% 4 4 3 3 5% 6% 52%	2200
	11th to 20th	Day	15% 5% 2 6% 4 4 4 3 5% 6% 45%	2026
	21st to end	Day	20% 7% 2 7% 4 4 4 3 4 5% 40%	1980
November	1st to 10th	Day	11% 6% 2 5% 4 4 4 3 5% 7% 51%	1852
	11th to 20th	Day	18% 9% 2 7% 4 3 2 3 4 6% 41%	1890
	21st to end	Day	18% 10% 3 8% 4 4 3 3 4 5% 37%	1890
December	1st to 10th	Day	13% 10% 3 8% 4 4 4 2 4 4 43%	2898
	11th to 20th	Day	16% 14% 5% 9% 5% 4 5% 3 5% 6% 28%	3088
	21st to end	Day	30% 16% 6% 10% 5% 4 3 3 4 4 17%	4070
January	1st to 10th	Night	16% 13% 7% 10% 4 4 4 3 4 6% 29%	8232
	11th to 20th	Night	12% 16% 5% 11% 6% 6% 5% 3 4 5% 27%	8280
	21st to end	Night	18% 11% 4 8% 6% 4 4 4 5% 6% 30%	8759
February	1st to 10th	Night	19% 12% 4 9% 5% 4 3 4 4 5% 31%	2536
	11th to 20th	Night	16% 10% 4 9% 5% 4 4 3 5% 6% 34%	2458
	21st to end	Night	19% 11% 3 8% 4 3 4 3 5% 5% 36%	2076
March	1st to 10th	Night	20% 15% 3 6% 3 3 3 2 4 5% 36%	5493
	11th to 20th	Night	14% 6% 2 5% 4 3 4 3 4 7% 47%	5405
	21st to end	Night	18% 8% 3 8% 5% 5% 4 4 5% 6% 33%	5148
April	1st to 10th	Night	15% 8% 3 6% 4 4 4 3 5% 7% 40%	2100
	11th to 20th	Night	17% 7% 3 6% 4 3 4 3 4 6% 43%	2075
	21st to end	Night	16% 7% 2 7% 6% 5% 5% 5% 6% 5% 36%	2006
May	1st to 10th	Night	18% 10% 3 7% 4 5% 4 3 5% 7% 32%	4123
	11th to 20th	Night	15% 6% 3 7% 4 4 4 3 6% 9% 39%	4122
	21st to end	Night	14% 7% 2 7% 5% 5% 5% 4 6% 8% 37%	4147
June	1st to 10th	Night	11% 6% 3 5% 4 4 4 3 5% 7% 50%	1600
	11th to 20th	Night	9% 5% 2 6% 4 4 5% 3 6% 8% 51%	1600
	21st to end	Night	7% 5% 2 5% 4 5% 4 4 8% 11% 46%	1600
July	1st to 10th	Night	9% 5% 2 6% 3 4 4 3 6% 9% 49%	3618
	11th to 20th	Night	7% 5% 2 7% 4 5% 6% 4 7% 10% 44%	3617
	21st to end	Night	7% 7% 3 8% 5% 5% 6% 5% 7% 10% 38%	3947
August	1st to 10th	Night	7% 4 2 4 4 3 4 4 5% 9% 54%	2961
	11th to 20th	Night	6% 4 2 6% 4 4 4 4 6% 8% 51%	3200
	21st to end	Night	5% 3 1 4 3 4 4 3 6% 8% 57%	3586
September	1st to 10th	Night	11% 5% 2 5% 4 3 4 3 5% 6% 52%	2000
	11th to 20th	Night	6% 4 2 4 4 3 3 3 5% 8% 59%	2152
	21st to end	Night	13% 6% 2 5% 4 3 3 3 5% 7% 48%	2200
October	1st to 10th	Night	8% 4 2 6% 3 3 4 4 5% 6% 57%	2200
	11th to 20th	Night	16% 6% 2 4 2 3 3 3 4 6% 51%	2367
	21st to end	Night	18% 8% 2 5% 4 4 4 3 5% 6% 40%	2860
November	1st to 10th	Night	11% 7% 2 5% 4 4 4 3 4 5% 51%	2666
	11th to 20th	Night	13% 9% 3 6% 4 3 4 4 4 7% 44%	2730
	21st to end	Night	21% 10% 4 6% 4 4 3 2 4 5% 36%	2730
December	1st to 10th	Night	16% 10% 3 8% 4 3 3 3 4 4 42%	4500
	11th to 20th	Night	18% 11% 4 9% 5% 5% 4 3 4 5% 32%	5339
	21st to end	Night	30% 16% 5% 9% 4 4 3 3 3 5% 19%	7150

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 11% 22% 7% 1	4692
	11th to 20th	Day	62% 3 10% 13% 11% 2	4710
	21st to end	Day	64% 2 7% 18% 6% 2	5452
February	1st to 10th	Day	54% 4 11% 20% 9% 2	2082
	11th to 20th	Day	54% 5% 10% 21% 9% 1	2058
	21st to end	Day	52% 4 9% 23% 10% 2	1730
March	1st to 10th	Day	52% 3 6% 20% 17% 3	4580
	11th to 20th	Day	40% 4 10% 32% 13% 1	4761
	21st to end	Day	51% 5% 12% 23% 8% 1	6069
April	1st to 10th	Day	47% 6% 12% 22% 13% 1	2520
	11th to 20th	Day	45% 5% 10% 25% 11% 3	2494
	21st to end	Day	47% 5% 11% 24% 10% 3	2612
May	1st to 10th	Day	50% 7% 13% 20% 10%	6027
	11th to 20th	Day	47% 5% 10% 26% 11%	5995
	21st to end	Day	45% 6% 12% 21% 14% 2	6964
June	1st to 10th	Day	35% 7% 13% 25% 16% 4	2801
	11th to 20th	Day	33% 8% 13% 23% 21% 4	2800
	21st to end	Day	36% 8% 16% 20% 18% 3	2800
July	1st to 10th	Day	35% 4 11% 31% 17% 2	6291
	11th to 20th	Day	41% 6% 14% 25% 13% 1	6285
	21st to end	Day	44% 4 17% 23% 11% 1	6728
August	1st to 10th	Day	30% 5% 15% 33% 16% 1	4167
	11th to 20th	Day	36% 6% 15% 28% 15% 1	3885
	21st to end	Day	27% 4 16% 32% 16% 4	4311
September	1st to 10th	Day	35% 6% 10% 26% 19% 4	2400
	11th to 20th	Day	29% 8% 11% 25% 24% 3	2226
	21st to end	Day	34% 6% 10% 23% 25% 3	2200
October	1st to 10th	Day	23% 3 7% 28% 36% 3	3590
	11th to 20th	Day	30% 3 8% 26% 32% 1	3267
	21st to end	Day	39% 2 8% 25% 25% 1	3180
November	1st to 10th	Day	34% 4 13% 28% 17% 5%	1852
	11th to 20th	Day	46% 3 9% 22% 15% 4	1890
	21st to end	Day	51% 4 8% 22% 14% 1	1890
December	1st to 10th	Day	45% 3 11% 28% 12%	2898
	11th to 20th	Day	59% 3 10% 22% 6% 1	3085
	21st to end	Day	72% 3 10% 10% 4	4070
January	1st to 10th	Night	57% 3 11% 22% 6%	8233
	11th to 20th	Night	61% 3 8% 13% 12% 3	8280
	21st to end	Night	56% 2 10% 22% 9% 1	8759
February	1st to 10th	Night	56% 5% 12% 18% 8% 1	2536
	11th to 20th	Night	51% 4 11% 20% 12% 2	2459
	21st to end	Night	50% 4 10% 23% 11% 2	2076
March	1st to 10th	Night	53% 3 6% 23% 12% 4	5493
	11th to 20th	Night	38% 4 9% 28% 20% 2	5405
	21st to end	Night	51% 5% 9% 27% 8% 1	5148
April	1st to 10th	Night	43% 6% 10% 25% 14% 2	2100
	11th to 20th	Night	41% 5% 10% 21% 17% 5%	2075
	21st to end	Night	46% 6% 10% 23% 12% 3	2006
May	1st to 10th	Night	51% 6% 12% 20% 10% 1	4150
	11th to 20th	Night	43% 5% 12% 25% 15%	4123
	21st to end	Night	44% 7% 13% 20% 14% 3	4155
June	1st to 10th	Night	34% 6% 9% 25% 22% 4	1600
	11th to 20th	Night	33% 6% 10% 23% 22% 6%	1600
	21st to end	Night	29% 7% 16% 22% 20% 6%	1600
July	1st to 10th	Night	34% 5% 9% 27% 22% 3	3580
	11th to 20th	Night	36% 4 15% 27% 17% 1	3572
	21st to end	Night	41% 4 18% 24% 12% 2	3832
August	1st to 10th	Night	28% 5% 15% 37% 14% 2	2951
	11th to 20th	Night	30% 5% 15% 28% 20% 2	3230
	21st to end	Night	26% 4 13% 30% 22% 4	3586
September	1st to 10th	Night	32% 5% 10% 27% 20% 6%	2000
	11th to 20th	Night	25% 4 10% 27% 29% 5%	2152
	21st to end	Night	35% 5% 10% 21% 24% 5%	2200
October	1st to 10th	Night	20% 4 6% 23% 44% 3	3590
	11th to 20th	Night	26% 2 8% 26% 36% 3	3852
	21st to end	Night	35% 3 8% 24% 25% 5%	4610
November	1st to 10th	Night	35% 5% 8% 26% 22% 5%	2666
	11th to 20th	Night	41% 4 10% 25% 18% 3	2730
	21st to end	Night	51% 3 10% 22% 13% 1	2730
December	1st to 10th	Night	48% 3 11% 25% 13%	4500
	11th to 20th	Night	55% 3 12% 19% 11%	5341
	21st to end	Night	70% 3 10% 12% 5% 1	7150

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% 18% 33% 17% 7% 1	330
	11th to 20th	Day	26% 19% 35% 16% 3	330
	21st to end	Day	23% 23% 33% 18% 3	363
February	1st to 10th	Day	25% 16% 36% 19% 4	330
	11th to 20th	Day	27% 20% 34% 14% 4 1	330
	21st to end	Day	27% 15% 41% 14% 3	273
March	1st to 10th	Day	22% 20% 39% 16% 3	330
	11th to 20th	Day	29% 19% 34% 14% 5%	393
	21st to end	Day	28% 17% 32% 17% 6%	594
April	1st to 10th	Day	21% 17% 32% 22% 6% 1	540
	11th to 20th	Day	20% 19% 27% 22% 11% 1	532
	21st to end	Day	20% 15% 34% 20% 8% 2	540
May	1st to 10th	Day	21% 13% 30% 24% 10% 2	543
	11th to 20th	Day	19% 9% 29% 24% 13% 5%	567
	21st to end	Day	13% 6% 29% 26% 18% 8%	783
June	1st to 10th	Day	12% 5% 23% 32% 22% 6%	731
	11th to 20th	Day	12% 5% 22% 32% 22% 7%	730
	21st to end	Day	12% 5% 27% 27% 22% 8%	730
July	1st to 10th	Day	11% 4 14% 27% 25% 20%	721
	11th to 20th	Day	7% 3 19% 32% 27% 13%	718
	21st to end	Day	11% 3 13% 30% 33% 10%	794
August	1st to 10th	Day	9% 2 13% 29% 32% 15%	528
	11th to 20th	Day	14% 2 15% 31% 29% 11%	519
	21st to end	Day	4 3 13% 32% 33% 15%	583
September	1st to 10th	Day	9% 4 17% 28% 30% 11%	530
	11th to 20th	Day	8% 2 11% 30% 30% 18%	530
	21st to end	Day	14% 7% 22% 23% 22% 13%	530
October	1st to 10th	Day	11% 4 24% 32% 22% 8%	530
	11th to 20th	Day	14% 15% 29% 23% 15% 4	365
	21st to end	Day	24% 18% 32% 20% 6%	363
November	1st to 10th	Day	13% 15% 35% 22% 12% 2	330
	11th to 20th	Day	23% 16% 32% 18% 10% 2	330
	21st to end	Day	24% 13% 35% 21% 7%	330
December	1st to 10th	Day	16% 21% 39% 16% 6% 2	330
	11th to 20th	Day	24% 15% 36% 19% 5% 1	330
	21st to end	Day	36% 13% 32% 15% 4	363
January	1st to 10th	Night	22% 13% 34% 26% 4	1050
	11th to 20th	Night	25% 15% 36% 20% 4	1050
	21st to end	Night	22% 14% 37% 24% 3	1155
February	1st to 10th	Night	25% 11% 36% 25% 2	856
	11th to 20th	Night	23% 14% 37% 24% 2	823
	21st to end	Night	25% 11% 38% 23% 3	692
March	1st to 10th	Night	23% 14% 34% 25% 4	840
	11th to 20th	Night	23% 12% 35% 25% 5%	840
	21st to end	Night	24% 8% 33% 29% 6%	730
April	1st to 10th	Night	18% 13% 34% 30% 5%	630
	11th to 20th	Night	20% 12% 29% 28% 11%	623
	21st to end	Night	18% 9% 36% 30% 7% 1	630
May	1st to 10th	Night	19% 7% 31% 33% 10%	630
	11th to 20th	Night	14% 5% 28% 35% 16% 1	621
	21st to end	Night	11% 3 23% 38% 23% 2	683
June	1st to 10th	Night	11% 5% 20% 42% 22% 1	600
	11th to 20th	Night	11% 2 21% 43% 22% 1	600
	21st to end	Night	8% 1 21% 41% 27% 1	600
July	1st to 10th	Night	9% 2 11% 34% 37% 7%	585
	11th to 20th	Night	6% 3 13% 38% 35% 4	582
	21st to end	Night	6% 2 12% 44% 33% 4	657
August	1st to 10th	Night	9% 2 10% 39% 38% 3	597
	11th to 20th	Night	7% 2 12% 40% 35% 5%	594
	21st to end	Night	8% 1 11% 36% 39% 5%	660
September	1st to 10th	Night	11% 3 15% 37% 30% 5%	600
	11th to 20th	Night	7% 2 15% 36% 36% 4	752
	21st to end	Night	15% 5% 19% 32% 25% 4	800
October	1st to 10th	Night	9% 6% 21% 38% 22% 4	800
	11th to 20th	Night	18% 10% 27% 29% 16% 1	800
	21st to end	Night	22% 10% 32% 28% 7%	880
November	1st to 10th	Night	15% 7% 33% 32% 12%	820
	11th to 20th	Night	18% 13% 32% 29% 8%	840
	21st to end	Night	25% 11% 30% 26% 7%	840
December	1st to 10th	Night	24% 10% 37% 25% 5%	908
	11th to 20th	Night	25% 10% 34% 24% 7% 1	1050
	21st to end	Night	31% 14% 31% 21% 3	1155

Page generated at 2026-05-29 01:53:27. Version ac07

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