Baxter State Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Baxter State Park 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% 13% 5% 11% 6% 5% 5% 4 5% 6% 26%	131610
	Night	13% 13% 5% 12% 7% 6% 5% 3 5% 5% 25%	131634
Transparency	Day	51% 10% 11% 17% 9% 1	135097
	Night	50% 12% 12% 17% 9% 1	136235
Seeing	Day	26% 24% 29% 15% 6% 1	17764
	Night	22% 21% 29% 21% 7%	26057

By Month

Percentage Cloud Cover NE (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	8% 16% 6% 18% 8% 7% 6% 3 4 5% 21%	4465
	11th to 20th	Day	7% 14% 6% 22% 14% 9% 4 3 3 3 16%	4650
	21st to end	Day	5% 8% 5% 15% 9% 10% 9% 5% 7% 7% 20%	5124
February	1st to 10th	Day	11% 13% 5% 14% 11% 7% 5% 4 5% 5% 19%	1847
	11th to 20th	Day	10% 15% 8% 16% 8% 7% 5% 3 4 3 21%	1932
	21st to end	Day	8% 16% 6% 13% 7% 6% 5% 4 4 4 26%	1730
March	1st to 10th	Day	13% 19% 5% 13% 7% 6% 4 3 3 3 22%	4576
	11th to 20th	Day	12% 18% 7% 12% 6% 4 4 3 5% 6% 23%	5086
	21st to end	Day	17% 16% 7% 13% 7% 4 3 2 3 5% 22%	5603
April	1st to 10th	Day	16% 18% 5% 11% 6% 4 4 3 4 4 24%	2520
	11th to 20th	Day	18% 17% 4 9% 5% 3 3 3 4 4 30%	2689
	21st to end	Day	19% 15% 5% 8% 4 3 4 3 4 5% 30%	2730
May	1st to 10th	Day	19% 15% 5% 10% 6% 5% 5% 4 4 4 22%	6016
	11th to 20th	Day	19% 13% 4 9% 6% 5% 5% 4 5% 5% 24%	6163
	21st to end	Day	16% 12% 4 10% 6% 5% 5% 4 6% 6% 25%	7560
June	1st to 10th	Day	23% 13% 3 8% 5% 5% 5% 3 6% 6% 24%	3000
	11th to 20th	Day	18% 9% 3 7% 5% 5% 5% 4 6% 7% 30%	3000
	21st to end	Day	23% 11% 3 9% 5% 5% 5% 4 6% 6% 22%	3000
July	1st to 10th	Day	14% 9% 4 10% 7% 7% 7% 6% 8% 7% 22%	6820
	11th to 20th	Day	13% 8% 3 8% 5% 5% 6% 4 6% 8% 32%	6366
	21st to end	Day	12% 8% 3 7% 5% 5% 5% 4 6% 8% 36%	6926
August	1st to 10th	Day	17% 8% 3 8% 6% 6% 6% 5% 6% 7% 28%	4278
	11th to 20th	Day	15% 9% 4 9% 7% 6% 6% 6% 7% 7% 24%	4175
	21st to end	Day	14% 9% 3 7% 4 5% 5% 4 6% 7% 34%	4675
September	1st to 10th	Day	13% 8% 3 6% 5% 4 4 3 5% 6% 41%	2330
	11th to 20th	Day	14% 8% 3 6% 5% 4 3 3 5% 4 46%	2200
	21st to end	Day	15% 9% 3 7% 5% 5% 4 4 5% 6% 38%	2200
October	1st to 10th	Day	15% 11% 4 8% 5% 4 4 3 4 7% 34%	2140
	11th to 20th	Day	18% 15% 4 9% 4 4 4 3 4 6% 28%	1945
	21st to end	Day	18% 16% 5% 11% 7% 4 3 3 4 6% 24%	1980
November	1st to 10th	Day	16% 18% 4 9% 5% 3 4 3 3 6% 29%	1851
	11th to 20th	Day	13% 16% 6% 13% 6% 4 4 3 4 6% 25%	1775
	21st to end	Day	16% 15% 5% 13% 7% 5% 5% 4 4 6% 20%	1667
December	1st to 10th	Day	12% 17% 6% 18% 8% 7% 5% 3 4 4 15%	2350
	11th to 20th	Day	13% 17% 9% 11% 5% 5% 3 3 4 4 28%	2688
	21st to end	Day	12% 17% 6% 13% 7% 4 5% 3 4 4 24%	3553
January	1st to 10th	Night	8% 14% 7% 17% 12% 8% 6% 4 4 4 15%	8434
	11th to 20th	Night	9% 15% 7% 21% 13% 8% 5% 3 4 3 12%	8235
	21st to end	Night	5% 9% 4 16% 9% 9% 9% 4 6% 5% 22%	9057
February	1st to 10th	Night	9% 14% 5% 13% 8% 8% 7% 4 5% 5% 22%	2772
	11th to 20th	Night	9% 15% 8% 14% 8% 7% 5% 4 5% 5% 20%	2572
	21st to end	Night	11% 13% 4 10% 8% 7% 4 3 5% 5% 28%	2076
March	1st to 10th	Night	15% 17% 7% 14% 6% 4 6% 3 3 4 20%	5484
	11th to 20th	Night	11% 17% 6% 12% 7% 5% 4 4 5% 5% 22%	5092
	21st to end	Night	17% 16% 5% 11% 6% 4 4 3 5% 6% 23%	5556
April	1st to 10th	Night	18% 18% 5% 9% 4 3 4 3 4 5% 26%	2100
	11th to 20th	Night	18% 14% 3 8% 4 4 4 3 6% 5% 31%	1879
	21st to end	Night	19% 14% 4 10% 6% 4 3 3 4 5% 28%	1890
May	1st to 10th	Night	19% 12% 4 11% 6% 5% 5% 4 5% 6% 25%	4144
	11th to 20th	Night	19% 13% 3 8% 5% 4 5% 4 5% 6% 28%	3993
	21st to end	Night	17% 9% 2 9% 5% 4 4 3 5% 7% 34%	3577
June	1st to 10th	Night	23% 11% 3 8% 4 4 4 3 5% 7% 28%	1400
	11th to 20th	Night	15% 9% 4 7% 5% 5% 5% 4 6% 7% 34%	1400
	21st to end	Night	18% 12% 5% 8% 4 4 5% 4 6% 6% 30%	1400
July	1st to 10th	Night	14% 10% 4 10% 6% 5% 4 3 5% 7% 32%	3160
	11th to 20th	Night	13% 8% 4 10% 7% 5% 5% 3 6% 7% 32%	3590
	21st to end	Night	10% 8% 3 8% 5% 5% 5% 4 6% 7% 37%	3926
August	1st to 10th	Night	17% 10% 3 9% 6% 5% 5% 4 6% 7% 30%	2838
	11th to 20th	Night	12% 8% 4 10% 6% 7% 6% 5% 7% 7% 29%	2872
	21st to end	Night	12% 9% 3 7% 4 4 4 3 5% 6% 44%	3223
September	1st to 10th	Night	12% 7% 2 6% 4 4 4 4 5% 7% 44%	2066
	11th to 20th	Night	13% 8% 3 6% 3 3 3 3 5% 6% 46%	2200
	21st to end	Night	13% 10% 3 9% 5% 4 4 3 5% 6% 39%	2200
October	1st to 10th	Night	16% 8% 3 7% 5% 3 5% 4 5% 7% 39%	2260
	11th to 20th	Night	16% 14% 3 9% 5% 4 5% 4 4 5% 32%	2450
	21st to end	Night	18% 15% 4 10% 4 5% 5% 3 5% 6% 26%	2860
November	1st to 10th	Night	17% 13% 5% 10% 5% 5% 5% 4 4 5% 27%	2667
	11th to 20th	Night	13% 15% 5% 13% 6% 4 4 3 4 4 28%	2842
	21st to end	Night	14% 15% 6% 14% 9% 6% 4 4 4 5% 20%	2951
December	1st to 10th	Night	12% 15% 6% 21% 11% 9% 5% 3 3 3 12%	5060
	11th to 20th	Night	14% 17% 6% 14% 8% 6% 5% 3 4 4 20%	5741
	21st to end	Night	14% 17% 6% 12% 8% 5% 4 2 3 3 25%	7667

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	54% 11% 12% 15% 8% 1	4466
	11th to 20th	Day	58% 15% 7% 13% 7% 1	4680
	21st to end	Day	49% 13% 8% 13% 16% 1	5124
February	1st to 10th	Day	59% 9% 8% 14% 8% 2	1847
	11th to 20th	Day	59% 10% 9% 13% 8% 1	1940
	21st to end	Day	54% 9% 8% 17% 10% 3	1730
March	1st to 10th	Day	60% 9% 6% 10% 13% 4	4579
	11th to 20th	Day	56% 10% 15% 11% 7% 1	5086
	21st to end	Day	59% 8% 6% 14% 10% 3	5603
April	1st to 10th	Day	60% 6% 9% 14% 10% 2	2520
	11th to 20th	Day	54% 7% 8% 17% 12% 1	2689
	21st to end	Day	55% 5% 8% 18% 11% 3	2730
May	1st to 10th	Day	59% 8% 8% 16% 8% 1	6027
	11th to 20th	Day	56% 9% 12% 16% 5% 2	6167
	21st to end	Day	53% 10% 10% 15% 11% 1	7560
June	1st to 10th	Day	56% 7% 12% 17% 8%	3000
	11th to 20th	Day	48% 8% 12% 19% 10% 2	3000
	21st to end	Day	58% 8% 12% 14% 8% 1	3000
July	1st to 10th	Day	49% 13% 16% 16% 6%	6745
	11th to 20th	Day	42% 12% 14% 27% 6%	6290
	21st to end	Day	40% 10% 14% 27% 9%	6728
August	1st to 10th	Day	49% 10% 14% 22% 6%	4264
	11th to 20th	Day	48% 12% 16% 18% 5%	4214
	21st to end	Day	41% 11% 15% 20% 13%	4675
September	1st to 10th	Day	39% 9% 13% 24% 13% 1	2330
	11th to 20th	Day	39% 6% 12% 27% 15% 1	2200
	21st to end	Day	43% 8% 10% 26% 13% 1	2200
October	1st to 10th	Day	51% 9% 12% 20% 8%	3491
	11th to 20th	Day	42% 15% 12% 21% 10%	3148
	21st to end	Day	43% 9% 18% 17% 13%	3180
November	1st to 10th	Day	53% 9% 12% 17% 8% 1	1851
	11th to 20th	Day	53% 9% 12% 16% 8% 2	1775
	21st to end	Day	58% 11% 14% 13% 4	1667
December	1st to 10th	Day	58% 15% 9% 10% 7%	2350
	11th to 20th	Day	51% 10% 12% 11% 14% 3	2688
	21st to end	Day	56% 9% 8% 13% 9% 5%	3553
January	1st to 10th	Night	55% 16% 11% 12% 6%	8434
	11th to 20th	Night	62% 15% 10% 9% 4 1	8280
	21st to end	Night	47% 14% 8% 14% 14% 2	9057
February	1st to 10th	Night	54% 11% 10% 15% 9% 2	2772
	11th to 20th	Night	58% 10% 9% 14% 8% 1	2575
	21st to end	Night	50% 9% 10% 17% 12% 2	2076
March	1st to 10th	Night	59% 10% 7% 13% 9% 2	5494
	11th to 20th	Night	54% 11% 15% 11% 8% 1	5093
	21st to end	Night	56% 7% 7% 16% 13% 1	5556
April	1st to 10th	Night	56% 7% 7% 15% 12% 3	2100
	11th to 20th	Night	49% 7% 10% 19% 14% 2	1879
	21st to end	Night	55% 6% 8% 17% 11% 3	1890
May	1st to 10th	Night	54% 11% 12% 14% 9%	4150
	11th to 20th	Night	52% 10% 12% 20% 5% 1	3994
	21st to end	Night	44% 10% 14% 19% 11% 1	3578
June	1st to 10th	Night	54% 7% 11% 19% 9%	1400
	11th to 20th	Night	46% 9% 13% 20% 11% 2	1400
	21st to end	Night	51% 9% 14% 17% 9%	1400
July	1st to 10th	Night	44% 12% 17% 22% 7%	3125
	11th to 20th	Night	41% 13% 14% 27% 4	3543
	21st to end	Night	34% 15% 18% 24% 8%	3809
August	1st to 10th	Night	49% 9% 16% 23% 4	2828
	11th to 20th	Night	42% 14% 17% 20% 6% 1	2899
	21st to end	Night	36% 10% 16% 22% 13% 3	3223
September	1st to 10th	Night	34% 8% 16% 30% 11% 1	2066
	11th to 20th	Night	37% 6% 13% 30% 13%	2200
	21st to end	Night	42% 8% 12% 23% 14% 1	2200
October	1st to 10th	Night	42% 11% 12% 23% 11%	3689
	11th to 20th	Night	38% 16% 11% 25% 10%	3986
	21st to end	Night	41% 11% 18% 19% 10% 1	4610
November	1st to 10th	Night	50% 12% 12% 18% 7% 1	2667
	11th to 20th	Night	50% 10% 13% 16% 9% 2	2842
	21st to end	Night	54% 11% 17% 12% 5%	2951
December	1st to 10th	Night	55% 20% 10% 11% 4	5060
	11th to 20th	Night	53% 13% 8% 12% 13%	5742
	21st to end	Night	55% 10% 8% 13% 11% 2	7667

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	30% 32% 28% 10%	220
	11th to 20th	Day	34% 31% 26% 7% 1	220
	21st to end	Day	26% 29% 34% 8% 3	242
February	1st to 10th	Day	26% 27% 30% 13% 4 1	387
	11th to 20th	Day	30% 32% 28% 8% 2	473
	21st to end	Day	25% 34% 28% 11% 2	446
March	1st to 10th	Day	30% 31% 28% 9% 3	540
	11th to 20th	Day	30% 28% 27% 12% 3 1	540
	21st to end	Day	33% 27% 23% 12% 5% 1	594
April	1st to 10th	Day	36% 28% 21% 10% 4 1	540
	11th to 20th	Day	35% 28% 23% 10% 3 2	532
	21st to end	Day	30% 26% 29% 10% 2 1	540
May	1st to 10th	Day	34% 23% 28% 12% 3 1	543
	11th to 20th	Day	28% 26% 29% 13% 4 1	567
	21st to end	Day	25% 25% 30% 15% 4	814
June	1st to 10th	Day	27% 21% 30% 14% 6% 1	730
	11th to 20th	Day	23% 19% 30% 19% 8% 1	730
	21st to end	Day	25% 17% 32% 17% 8% 1	730
July	1st to 10th	Day	17% 20% 33% 20% 9% 1	720
	11th to 20th	Day	17% 18% 39% 17% 8% 1	529
	21st to end	Day	18% 15% 36% 24% 6% 1	576
August	1st to 10th	Day	17% 16% 34% 24% 8% 1	526
	11th to 20th	Day	17% 15% 28% 28% 10% 2	519
	21st to end	Day	18% 18% 31% 20% 10% 2	583
September	1st to 10th	Day	17% 19% 31% 22% 9% 3	530
	11th to 20th	Day	19% 17% 27% 23% 10% 5%	530
	21st to end	Day	20% 20% 29% 18% 9% 5%	530
October	1st to 10th	Day	18% 20% 30% 20% 9% 2	497
	11th to 20th	Day	27% 25% 26% 13% 6% 2	420
	21st to end	Day	28% 28% 26% 15% 3	462
November	1st to 10th	Day	31% 25% 25% 16% 4	425
	11th to 20th	Day	26% 28% 28% 11% 6%	430
	21st to end	Day	34% 26% 25% 12% 3	417
December	1st to 10th	Day	28% 30% 27% 12% 3	220
	11th to 20th	Day	38% 29% 23% 6% 4	220
	21st to end	Day	30% 33% 23% 10% 4	242
January	1st to 10th	Night	21% 28% 32% 16% 2	878
	11th to 20th	Night	24% 27% 30% 16% 3	840
	21st to end	Night	17% 28% 36% 15% 3	924
February	1st to 10th	Night	20% 30% 31% 16% 3	840
	11th to 20th	Night	24% 29% 31% 14% 2	823
	21st to end	Night	21% 28% 34% 15% 2	692
March	1st to 10th	Night	26% 25% 33% 16% 1	840
	11th to 20th	Night	24% 25% 28% 17% 6%	840
	21st to end	Night	23% 24% 29% 19% 6%	924
April	1st to 10th	Night	32% 23% 27% 14% 5%	840
	11th to 20th	Night	26% 23% 26% 19% 6%	635
	21st to end	Night	30% 20% 25% 19% 6%	630
May	1st to 10th	Night	27% 19% 26% 23% 5%	630
	11th to 20th	Night	25% 17% 29% 22% 7%	570
	21st to end	Night	22% 13% 33% 25% 7%	455
June	1st to 10th	Night	26% 13% 29% 24% 9%	400
	11th to 20th	Night	19% 14% 23% 32% 12%	400
	21st to end	Night	23% 13% 27% 28% 9%	400
July	1st to 10th	Night	16% 12% 29% 32% 10% 1	390
	11th to 20th	Night	14% 10% 29% 35% 12% 1	388
	21st to end	Night	17% 9% 29% 32% 13%	438
August	1st to 10th	Night	17% 8% 26% 34% 15%	546
	11th to 20th	Night	15% 8% 28% 31% 17% 1	592
	21st to end	Night	15% 10% 27% 33% 14% 1	660
September	1st to 10th	Night	14% 13% 28% 29% 14% 1	787
	11th to 20th	Night	15% 15% 23% 31% 14% 2	800
	21st to end	Night	18% 15% 28% 25% 13% 1	800
October	1st to 10th	Night	20% 15% 27% 26% 11% 1	800
	11th to 20th	Night	23% 18% 29% 21% 8% 1	800
	21st to end	Night	26% 24% 27% 18% 4	880
November	1st to 10th	Night	27% 20% 28% 19% 6%	820
	11th to 20th	Night	22% 27% 26% 17% 7% 1	900
	21st to end	Night	25% 27% 26% 17% 4 1	950
December	1st to 10th	Night	25% 25% 33% 13% 3 1	950
	11th to 20th	Night	28% 26% 27% 15% 3	950
	21st to end	Night	28% 27% 28% 14% 3	1045

Page generated at 2026-05-29 01:53:25. Version ac07

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