Benton Harbor
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Benton Harbor clear sky chart from 2005-11-06 to 2024-04-03.

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% 5% 7% 6% 3 4 4 5% 7% 34%	78759
	Night	17% 13% 6% 8% 6% 3 4 4 4 6% 30%	81413
Transparency	Day	52% 2 11% 22% 12% 2	78460
	Night	58% 2 10% 18% 10% 1	81233
Seeing	Day	19% 11% 28% 24% 13% 4	14871
	Night	23% 9% 27% 28% 12% 1	24919

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	15% 23% 11% 12% 8% 4 3 4 4 5% 12%	2527
	11th to 20th	Day	14% 18% 10% 15% 13% 9% 7% 3 2 3 8%	2530
	21st to end	Day	24% 23% 8% 12% 7% 3 3 3 3 4 11%	2783
February	1st to 10th	Day	14% 15% 7% 12% 12% 4 6% 4 3 4 19%	1790
	11th to 20th	Day	14% 13% 8% 13% 10% 4 4 3 4 5% 22%	1848
	21st to end	Day	16% 14% 7% 11% 7% 4 5% 5% 4 6% 23%	1570
March	1st to 10th	Day	14% 12% 7% 9% 6% 4 5% 4 5% 7% 28%	1900
	11th to 20th	Day	13% 9% 5% 8% 6% 3 5% 5% 6% 7% 34%	1997
	21st to end	Day	18% 11% 4 8% 6% 3 5% 4 5% 7% 28%	2431
April	1st to 10th	Day	18% 11% 5% 7% 4 2 4 4 5% 7% 33%	2184
	11th to 20th	Day	16% 11% 3 4 5% 2 4 4 5% 8% 38%	2137
	21st to end	Day	18% 9% 3 6% 5% 3 4 4 5% 8% 35%	2340
May	1st to 10th	Day	17% 9% 3 5% 5% 3 5% 5% 6% 7% 35%	2340
	11th to 20th	Day	18% 8% 3 5% 4 3 3 4 5% 7% 40%	2314
	21st to end	Day	11% 5% 2 5% 5% 4 5% 5% 6% 9% 43%	2725
June	1st to 10th	Day	9% 5% 2 5% 5% 3 4 5% 6% 8% 48%	2520
	11th to 20th	Day	10% 4 2 4 5% 3 4 5% 5% 8% 49%	2520
	21st to end	Day	12% 4 3 5% 5% 2 4 5% 6% 8% 46%	2520
July	1st to 10th	Day	8% 4 1 5% 4 3 4 5% 5% 8% 53%	2520
	11th to 20th	Day	10% 4 2 4 4 2 4 5% 6% 10% 50%	2520
	21st to end	Day	6% 4 2 4 5% 3 5% 5% 6% 10% 50%	2743
August	1st to 10th	Day	7% 5% 2 4 5% 3 5% 5% 8% 9% 47%	2370
	11th to 20th	Day	9% 5% 2 4 5% 3 4 6% 5% 9% 47%	2259
	21st to end	Day	9% 4 2 5% 5% 2 4 4 6% 8% 51%	2376
September	1st to 10th	Day	11% 6% 2 5% 5% 2 5% 5% 6% 7% 47%	2159
	11th to 20th	Day	13% 4 2 4 4 4 4 4 7% 7% 46%	1980
	21st to end	Day	13% 5% 3 6% 5% 3 4 5% 6% 9% 42%	1980
October	1st to 10th	Day	17% 8% 3 6% 3 2 4 4 4 4 44%	1980
	11th to 20th	Day	24% 9% 4 6% 5% 3 4 5% 6% 6% 29%	1763
	21st to end	Day	26% 10% 3 7% 7% 4 6% 4 5% 6% 24%	1782
November	1st to 10th	Day	15% 13% 4 6% 5% 3 3 5% 4 6% 37%	1672
	11th to 20th	Day	17% 19% 5% 9% 5% 3 5% 4 4 6% 23%	1710
	21st to end	Day	22% 17% 7% 9% 5% 2 4 3 4 5% 22%	1710
December	1st to 10th	Day	17% 21% 13% 11% 4 3 3 3 4 4 18%	1558
	11th to 20th	Day	14% 22% 12% 12% 6% 2 3 3 4 4 16%	1918
	21st to end	Day	22% 23% 9% 11% 8% 3 3 3 3 5% 10%	2783
January	1st to 10th	Night	17% 23% 11% 12% 7% 3 4 4 4 4 11%	4428
	11th to 20th	Night	16% 21% 11% 15% 8% 8% 5% 2 2 3 9%	4440
	21st to end	Night	25% 20% 11% 12% 7% 3 4 3 3 3 10%	4884
February	1st to 10th	Night	16% 15% 7% 12% 10% 4 3 3 3 5% 20%	2384
	11th to 20th	Night	14% 15% 7% 13% 9% 4 5% 3 4 5% 22%	2218
	21st to end	Night	19% 14% 7% 11% 6% 3 3 3 3 5% 25%	1884
March	1st to 10th	Night	17% 11% 6% 8% 6% 3 4 4 4 6% 30%	2280
	11th to 20th	Night	13% 9% 4 7% 5% 3 4 4 5% 6% 39%	2182
	21st to end	Night	21% 9% 5% 8% 5% 3 4 4 4 6% 31%	2183
April	1st to 10th	Night	16% 9% 4 6% 5% 4 5% 4 5% 6% 35%	1820
	11th to 20th	Night	20% 9% 2 6% 4 3 4 5% 4 5% 37%	1771
	21st to end	Night	20% 6% 3 7% 5% 3 4 4 6% 6% 36%	1620
May	1st to 10th	Night	17% 9% 3 5% 5% 4 4 5% 6% 8% 34%	1620
	11th to 20th	Night	18% 6% 3 6% 4 3 3 4 5% 8% 39%	1575
	21st to end	Night	11% 5% 3 6% 5% 3 4 5% 7% 10% 41%	1551
June	1st to 10th	Night	10% 5% 2 4 5% 3 4 5% 6% 10% 48%	1440
	11th to 20th	Night	10% 6% 2 4 6% 3 5% 6% 6% 8% 45%	1440
	21st to end	Night	9% 5% 2 6% 5% 3 6% 5% 7% 10% 42%	1440
July	1st to 10th	Night	7% 3 2 4 5% 3 5% 5% 6% 9% 51%	1440
	11th to 20th	Night	9% 3 2 4 5% 2 3 5% 6% 8% 52%	1440
	21st to end	Night	6% 4 2 4 5% 4 5% 5% 7% 8% 50%	1575
August	1st to 10th	Night	8% 3 2 4 5% 4 5% 5% 7% 10% 47%	1565
	11th to 20th	Night	9% 3 2 5% 5% 4 5% 5% 6% 7% 49%	1639
	21st to end	Night	9% 4 2 4 4 3 5% 4 5% 7% 52%	1980
September	1st to 10th	Night	11% 5% 3 5% 5% 3 4 4 5% 6% 49%	1800
	11th to 20th	Night	13% 4 2 4 3 3 3 4 5% 8% 51%	1962
	21st to end	Night	13% 6% 2 6% 4 3 5% 5% 6% 7% 43%	1980
October	1st to 10th	Night	17% 7% 2 5% 5% 3 3 4 4 5% 44%	1980
	11th to 20th	Night	23% 10% 3 5% 4 3 4 4 4 6% 34%	2192
	21st to end	Night	28% 11% 3 6% 5% 2 4 3 3 5% 29%	2574
November	1st to 10th	Night	16% 12% 4 6% 5% 3 4 4 4 5% 37%	2406
	11th to 20th	Night	18% 18% 6% 8% 4 3 4 3 5% 5% 25%	2470
	21st to end	Night	21% 19% 6% 7% 4 3 4 3 3 5% 25%	2470
December	1st to 10th	Night	19% 23% 11% 10% 6% 2 4 3 3 4 16%	2617
	11th to 20th	Night	16% 21% 11% 13% 7% 3 4 4 4 4 14%	3279
	21st to end	Night	25% 23% 7% 9% 6% 3 4 4 3 4 11%	4884

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	77% 1 10% 9% 2	2528
	11th to 20th	Day	86% 2 6% 6% 1	2530
	21st to end	Day	80% 1 7% 9% 2	2783
February	1st to 10th	Day	71% 2 9% 13% 5% 1	1790
	11th to 20th	Day	67% 2 9% 15% 7%	1858
	21st to end	Day	65% 2 10% 15% 7% 1	1570
March	1st to 10th	Day	59% 2 11% 19% 8%	1900
	11th to 20th	Day	50% 2 13% 23% 11% 2	1997
	21st to end	Day	58% 2 10% 23% 6% 1	2431
April	1st to 10th	Day	52% 3 10% 22% 13%	2184
	11th to 20th	Day	47% 3 9% 24% 15% 3	2137
	21st to end	Day	50% 1 12% 20% 14% 2	2340
May	1st to 10th	Day	49% 4 12% 24% 11% 1	2340
	11th to 20th	Day	46% 3 11% 24% 15% 2	2318
	21st to end	Day	40% 3 13% 27% 14% 2	2725
June	1st to 10th	Day	36% 3 12% 28% 20% 2	2520
	11th to 20th	Day	34% 3 12% 28% 21% 3	2520
	21st to end	Day	37% 3 16% 24% 17% 3	2520
July	1st to 10th	Day	31% 4 11% 30% 21% 4	2451
	11th to 20th	Day	32% 3 13% 30% 19% 3	2445
	21st to end	Day	31% 4 14% 30% 18% 3	2591
August	1st to 10th	Day	33% 3 14% 32% 16% 2	2355
	11th to 20th	Day	35% 4 15% 29% 16% 1	2259
	21st to end	Day	32% 3 12% 28% 20% 4	2376
September	1st to 10th	Day	37% 3 14% 25% 16% 4	2159
	11th to 20th	Day	36% 2 12% 33% 15% 2	1980
	21st to end	Day	41% 3 10% 28% 17% 1	1980
October	1st to 10th	Day	46% 3 9% 26% 16% 2	1980
	11th to 20th	Day	55% 2 11% 22% 9%	1763
	21st to end	Day	63% 2 10% 16% 7% 1	1782
November	1st to 10th	Day	49% 3 12% 21% 14% 1	1672
	11th to 20th	Day	64% 1 10% 18% 6% 1	1710
	21st to end	Day	66% 2 11% 17% 4	1710
December	1st to 10th	Day	73% 1 9% 13% 4	1558
	11th to 20th	Day	74% 1 11% 11% 2	1915
	21st to end	Day	80% 2 8% 9% 2	2783
January	1st to 10th	Night	79% 1 8% 9% 2	4428
	11th to 20th	Night	85% 1 6% 5% 2	4440
	21st to end	Night	83% 1 8% 7% 1	4884
February	1st to 10th	Night	69% 2 9% 13% 6% 1	2384
	11th to 20th	Night	67% 2 7% 17% 6%	2219
	21st to end	Night	65% 2 8% 17% 7% 2	1884
March	1st to 10th	Night	57% 2 11% 20% 9%	2280
	11th to 20th	Night	48% 2 12% 23% 13% 2	2182
	21st to end	Night	56% 2 10% 21% 10% 1	2183
April	1st to 10th	Night	51% 3 11% 22% 12% 1	1820
	11th to 20th	Night	50% 2 6% 21% 18% 3	1771
	21st to end	Night	50% 2 11% 19% 15% 3	1620
May	1st to 10th	Night	49% 2 12% 23% 12% 1	1620
	11th to 20th	Night	45% 3 10% 23% 17% 2	1576
	21st to end	Night	39% 4 13% 27% 14% 2	1552
June	1st to 10th	Night	33% 3 12% 30% 18% 3	1440
	11th to 20th	Night	37% 3 12% 25% 20% 2	1440
	21st to end	Night	38% 4 16% 25% 15% 2	1440
July	1st to 10th	Night	32% 2 12% 30% 19% 5%	1400
	11th to 20th	Night	29% 4 13% 27% 22% 4	1392
	21st to end	Night	32% 4 14% 25% 21% 4	1487
August	1st to 10th	Night	32% 3 14% 30% 19% 2	1556
	11th to 20th	Night	34% 4 14% 29% 17% 3	1639
	21st to end	Night	33% 3 9% 28% 22% 5%	1980
September	1st to 10th	Night	38% 3 11% 26% 18% 4	1800
	11th to 20th	Night	33% 3 7% 33% 22% 2	1962
	21st to end	Night	41% 3 9% 27% 18% 2	1980
October	1st to 10th	Night	43% 2 8% 26% 19% 2	1980
	11th to 20th	Night	54% 2 9% 21% 13% 1	2192
	21st to end	Night	60% 2 10% 19% 8% 1	2574
November	1st to 10th	Night	51% 3 8% 22% 14% 2	2406
	11th to 20th	Night	63% 2 10% 17% 7% 1	2470
	21st to end	Night	65% 2 11% 17% 5%	2470
December	1st to 10th	Night	75% 1 8% 12% 4	2617
	11th to 20th	Night	76% 2 9% 11% 2	3281
	21st to end	Night	80% 1 10% 8% 2	4884

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	22% 18% 35% 18% 6% 1	270
	11th to 20th	Day	24% 14% 39% 18% 4 1	270
	21st to end	Day	28% 14% 31% 23% 3	297
February	1st to 10th	Day	24% 22% 30% 17% 5% 1	270
	11th to 20th	Day	23% 28% 30% 16% 3	270
	21st to end	Day	26% 27% 36% 10% 2	225
March	1st to 10th	Day	21% 24% 36% 13% 4	270
	11th to 20th	Day	25% 18% 31% 19% 6% 1	367
	21st to end	Day	30% 16% 29% 19% 6% 1	506
April	1st to 10th	Day	27% 14% 34% 20% 5% 1	428
	11th to 20th	Day	24% 20% 27% 19% 8% 2	412
	21st to end	Day	27% 10% 33% 17% 9% 2	420
May	1st to 10th	Day	27% 14% 29% 20% 8% 2	423
	11th to 20th	Day	20% 10% 32% 23% 11% 4	460
	21st to end	Day	16% 7% 30% 25% 15% 6%	679
June	1st to 10th	Day	11% 7% 33% 30% 14% 5%	630
	11th to 20th	Day	13% 8% 28% 31% 17% 4	630
	21st to end	Day	13% 6% 32% 30% 15% 5%	630
July	1st to 10th	Day	9% 4 22% 31% 24% 10%	621
	11th to 20th	Day	12% 4 29% 32% 17% 6%	618
	21st to end	Day	8% 3 26% 36% 21% 6%	684
August	1st to 10th	Day	10% 2 18% 33% 25% 11%	489
	11th to 20th	Day	12% 4 23% 25% 28% 9%	439
	21st to end	Day	11% 5% 21% 32% 24% 9%	495
September	1st to 10th	Day	17% 4 20% 33% 18% 8%	450
	11th to 20th	Day	12% 3 19% 29% 25% 13%	450
	21st to end	Day	17% 12% 20% 24% 18% 10%	450
October	1st to 10th	Day	21% 7% 23% 28% 17% 4	450
	11th to 20th	Day	28% 13% 32% 22% 5%	324
	21st to end	Day	39% 9% 31% 17% 4	297
November	1st to 10th	Day	21% 17% 28% 25% 8% 1	270
	11th to 20th	Day	27% 20% 29% 19% 6%	270
	21st to end	Day	35% 12% 36% 14% 3	270
December	1st to 10th	Day	26% 22% 31% 14% 6%	270
	11th to 20th	Day	24% 25% 33% 14% 4 1	270
	21st to end	Day	26% 26% 31% 16% 1	297
January	1st to 10th	Night	27% 14% 32% 21% 5%	950
	11th to 20th	Night	28% 15% 32% 20% 5% 1	950
	21st to end	Night	26% 13% 32% 24% 4	1045
February	1st to 10th	Night	28% 11% 34% 23% 4	810
	11th to 20th	Night	25% 14% 32% 25% 4	743
	21st to end	Night	28% 15% 36% 18% 3	628
March	1st to 10th	Night	23% 14% 31% 25% 7% 1	760
	11th to 20th	Night	20% 12% 35% 26% 7% 1	760
	21st to end	Night	25% 8% 31% 28% 7% 1	720
April	1st to 10th	Night	21% 13% 33% 25% 8% 1	546
	11th to 20th	Night	26% 9% 30% 27% 7% 1	533
	21st to end	Night	22% 8% 31% 29% 8% 1	540
May	1st to 10th	Night	21% 6% 30% 32% 10% 1	540
	11th to 20th	Night	22% 4 24% 33% 15% 1	531
	21st to end	Night	13% 2 25% 39% 19% 2	584
June	1st to 10th	Night	14% 2 21% 42% 19% 1	540
	11th to 20th	Night	14% 2 26% 39% 17% 1	540
	21st to end	Night	11% 3 23% 37% 25% 1	540
July	1st to 10th	Night	10% 1 16% 38% 30% 5%	525
	11th to 20th	Night	11% 2 16% 39% 27% 4	522
	21st to end	Night	10% 1 14% 44% 29% 3	591
August	1st to 10th	Night	10% 1 12% 45% 30% 3	537
	11th to 20th	Night	10% 2 13% 39% 31% 6%	534
	21st to end	Night	12% 2 13% 37% 31% 4	594
September	1st to 10th	Night	15% 4 14% 38% 24% 6%	540
	11th to 20th	Night	13% 5% 16% 35% 27% 4	702
	21st to end	Night	18% 5% 23% 28% 22% 5%	720
October	1st to 10th	Night	22% 4 22% 31% 20% 1	720
	11th to 20th	Night	30% 11% 24% 26% 7% 1	720
	21st to end	Night	36% 11% 27% 21% 6%	792
November	1st to 10th	Night	26% 12% 29% 23% 10% 1	740
	11th to 20th	Night	30% 16% 29% 22% 4	760
	21st to end	Night	33% 11% 30% 22% 4	760
December	1st to 10th	Night	30% 18% 30% 18% 4	907
	11th to 20th	Night	30% 13% 33% 21% 3	950
	21st to end	Night	34% 15% 33% 17% 2	1045

Page generated at 2024-03-31 06:08:53. Version ac07

Copyright © 2024 Attilla Danko.