Haliburton County
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Haliburton County clear sky chart from 2005-11-06 to 2026-07-01.

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	16% 12% 4 9% 5% 4 4 3 5% 6% 30%	138705
	Night	16% 14% 5% 10% 5% 4 4 3 5% 6% 28%	133588
Transparency	Day	53% 6% 10% 20% 10% 1	142274
	Night	55% 6% 10% 18% 10% 1	138107
Seeing	Day	25% 17% 31% 18% 7% 2	16697
	Night	23% 14% 30% 23% 9% 1	25692

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	13% 16% 5% 14% 6% 5% 4 3 5% 5% 22%	4661
	11th to 20th	Day	9% 25% 11% 19% 8% 6% 4 2 3 3 11%	4728
	21st to end	Day	10% 17% 9% 19% 7% 6% 5% 3 4 4 16%	5780
February	1st to 10th	Day	12% 18% 6% 17% 9% 5% 3 3 3 3 19%	1890
	11th to 20th	Day	12% 16% 7% 15% 6% 5% 4 3 4 5% 23%	1843
	21st to end	Day	16% 18% 7% 12% 7% 4 4 4 4 4 21%	1606
March	1st to 10th	Day	18% 16% 5% 12% 6% 3 3 3 5% 6% 25%	4964
	11th to 20th	Day	12% 16% 6% 11% 6% 5% 5% 4 6% 6% 24%	5090
	21st to end	Day	18% 16% 4 9% 4 3 3 2 3 4 34%	5625
April	1st to 10th	Day	20% 15% 4 7% 5% 4 4 3 4 6% 27%	2520
	11th to 20th	Day	24% 12% 3 6% 3 5% 3 2 4 5% 33%	2544
	21st to end	Day	22% 13% 4 6% 4 4 4 2 4 5% 32%	2730
May	1st to 10th	Day	19% 8% 3 8% 5% 5% 4 4 5% 7% 32%	7935
	11th to 20th	Day	18% 9% 3 7% 5% 4 4 4 5% 7% 34%	8221
	21st to end	Day	19% 9% 2 6% 4 4 4 3 5% 6% 36%	9060
June	1st to 10th	Day	20% 9% 3 7% 5% 4 4 4 5% 7% 31%	2940
	11th to 20th	Day	16% 7% 3 6% 5% 5% 5% 4 7% 8% 34%	2949
	21st to end	Day	17% 8% 3 7% 5% 5% 5% 4 7% 7% 32%	3150
July	1st to 10th	Day	15% 6% 2 6% 5% 4 5% 5% 6% 10% 36%	6508
	11th to 20th	Day	12% 6% 2 6% 4 5% 4 3 5% 8% 45%	6360
	21st to end	Day	8% 6% 2 6% 4 4 4 4 6% 9% 46%	6819
August	1st to 10th	Day	15% 8% 3 8% 5% 5% 5% 4 6% 8% 33%	4234
	11th to 20th	Day	16% 8% 2 7% 4 5% 6% 4 7% 8% 33%	4174
	21st to end	Day	10% 5% 2 6% 4 6% 5% 5% 7% 10% 41%	4454
September	1st to 10th	Day	17% 8% 2 5% 4 5% 4 4 6% 7% 38%	2400
	11th to 20th	Day	13% 6% 2 5% 4 3 4 4 5% 7% 45%	2355
	21st to end	Day	19% 9% 3 8% 5% 4 5% 4 5% 6% 35%	2114
October	1st to 10th	Day	20% 9% 3 7% 5% 4 3 2 5% 7% 33%	2000
	11th to 20th	Day	25% 12% 3 9% 5% 5% 4 3 5% 5% 25%	2000
	21st to end	Day	28% 14% 4 9% 4 4 4 3 4 5% 21%	2186
November	1st to 10th	Day	19% 15% 3 8% 4 4 3 3 5% 6% 29%	1711
	11th to 20th	Day	17% 18% 7% 9% 5% 4 5% 4 5% 6% 22%	1680
	21st to end	Day	20% 24% 7% 10% 6% 5% 3 2 4 4 15%	1680
December	1st to 10th	Day	16% 26% 9% 11% 5% 4 4 3 4 4 12%	2680
	11th to 20th	Day	17% 22% 7% 17% 5% 3 2 2 2 3 18%	3066
	21st to end	Day	22% 21% 7% 13% 5% 3 2 2 3 4 18%	4048
January	1st to 10th	Night	13% 18% 9% 17% 7% 5% 4 3 4 4 16%	8234
	11th to 20th	Night	10% 20% 9% 22% 10% 5% 4 2 3 3 11%	8141
	21st to end	Night	10% 17% 9% 16% 9% 7% 5% 3 4 4 18%	8401
February	1st to 10th	Night	12% 19% 6% 12% 8% 6% 5% 3 5% 5% 19%	2730
	11th to 20th	Night	12% 16% 7% 13% 6% 6% 4 3 4 4 24%	2663
	21st to end	Night	14% 18% 5% 11% 7% 6% 5% 3 6% 5% 21%	2199
March	1st to 10th	Night	16% 15% 5% 12% 5% 4 3 3 4 5% 28%	5092
	11th to 20th	Night	9% 15% 6% 11% 6% 5% 5% 4 6% 7% 26%	5089
	21st to end	Night	19% 11% 4 9% 5% 4 4 3 5% 6% 30%	5547
April	1st to 10th	Night	21% 16% 4 7% 4 4 3 2 5% 5% 29%	2100
	11th to 20th	Night	18% 12% 4 7% 4 3 4 2 5% 7% 35%	2044
	21st to end	Night	19% 11% 3 8% 6% 5% 4 3 4 6% 32%	1890
May	1st to 10th	Night	20% 7% 2 7% 5% 5% 4 4 5% 7% 34%	4963
	11th to 20th	Night	17% 8% 3 6% 4 3 3 3 5% 7% 40%	4639
	21st to end	Night	19% 7% 2 5% 4 4 4 3 5% 7% 40%	5114
June	1st to 10th	Night	15% 10% 3 6% 4 4 4 3 6% 8% 36%	1680
	11th to 20th	Night	13% 9% 2 5% 4 4 4 4 6% 7% 43%	1658
	21st to end	Night	15% 9% 3 8% 5% 4 4 3 5% 7% 37%	1470
July	1st to 10th	Night	12% 7% 2 8% 5% 5% 5% 4 7% 8% 37%	3424
	11th to 20th	Night	14% 7% 2 5% 4 4 4 3 5% 7% 46%	3600
	21st to end	Night	10% 6% 2 5% 3 4 3 3 5% 7% 51%	4029
August	1st to 10th	Night	11% 4 2 6% 4 3 5% 5% 6% 7% 47%	2915
	11th to 20th	Night	15% 9% 3 7% 4 3 4 3 5% 6% 41%	2875
	21st to end	Night	13% 5% 2 5% 3 4 4 3 6% 8% 48%	3410
September	1st to 10th	Night	13% 6% 2 6% 4 4 4 4 6% 8% 45%	2000
	11th to 20th	Night	13% 6% 2 5% 4 3 4 3 4 6% 50%	2041
	21st to end	Night	19% 9% 3 6% 4 4 4 2 4 6% 40%	2285
October	1st to 10th	Night	19% 8% 3 6% 4 4 4 3 5% 6% 38%	2400
	11th to 20th	Night	23% 12% 4 8% 4 4 4 3 4 5% 29%	2400
	21st to end	Night	23% 15% 3 9% 5% 4 3 3 4 5% 26%	2652
November	1st to 10th	Night	21% 13% 3 8% 5% 4 4 2 5% 6% 30%	2805
	11th to 20th	Night	17% 16% 5% 8% 6% 4 4 3 5% 7% 26%	2940
	21st to end	Night	21% 20% 5% 10% 5% 5% 4 3 4 5% 18%	2940
December	1st to 10th	Night	19% 25% 7% 12% 6% 4 3 3 4 4 12%	4720
	11th to 20th	Night	16% 23% 7% 16% 5% 4 4 3 3 4 14%	5348
	21st to end	Night	22% 21% 7% 13% 6% 3 3 2 3 4 15%	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	62% 5% 10% 15% 7% 1	4662
	11th to 20th	Day	80% 4 4 6% 6% 1	4758
	21st to end	Day	72% 4 6% 9% 7% 1	5780
February	1st to 10th	Day	69% 5% 7% 13% 6% 1	1890
	11th to 20th	Day	63% 6% 9% 12% 9% 2	1852
	21st to end	Day	66% 5% 8% 13% 9% 1	1606
March	1st to 10th	Day	60% 5% 11% 8% 13% 1	4967
	11th to 20th	Day	58% 6% 13% 15% 6% 2	5090
	21st to end	Day	54% 4 7% 19% 14% 2	5625
April	1st to 10th	Day	58% 5% 8% 17% 11% 2	2520
	11th to 20th	Day	54% 5% 7% 20% 13% 1	2544
	21st to end	Day	55% 5% 8% 19% 11% 3	2730
May	1st to 10th	Day	49% 6% 11% 20% 11% 4	7944
	11th to 20th	Day	47% 7% 9% 21% 14% 1	8225
	21st to end	Day	46% 7% 10% 21% 13% 2	9061
June	1st to 10th	Day	51% 6% 9% 20% 14% 1	2940
	11th to 20th	Day	45% 7% 11% 23% 12% 1	2949
	21st to end	Day	48% 8% 13% 21% 10% 1	3150
July	1st to 10th	Day	41% 7% 15% 27% 10% 1	6439
	11th to 20th	Day	36% 6% 13% 31% 14%	6285
	21st to end	Day	33% 6% 15% 34% 12%	6623
August	1st to 10th	Day	48% 8% 13% 22% 9%	4221
	11th to 20th	Day	45% 8% 14% 25% 7%	4213
	21st to end	Day	36% 8% 13% 33% 9%	4454
September	1st to 10th	Day	43% 7% 13% 25% 10% 1	2400
	11th to 20th	Day	37% 7% 13% 30% 12% 1	2355
	21st to end	Day	49% 7% 11% 22% 11%	2114
October	1st to 10th	Day	46% 7% 13% 25% 9% 1	3260
	11th to 20th	Day	53% 6% 11% 19% 10% 1	3240
	21st to end	Day	60% 6% 11% 18% 5%	3512
November	1st to 10th	Day	55% 7% 13% 18% 7% 1	1711
	11th to 20th	Day	61% 8% 11% 13% 7% 1	1680
	21st to end	Day	73% 5% 9% 8% 4 1	1680
December	1st to 10th	Day	75% 5% 9% 7% 2	2680
	11th to 20th	Day	72% 5% 5% 12% 6%	3066
	21st to end	Day	71% 5% 5% 12% 7%	4048
January	1st to 10th	Night	70% 5% 8% 12% 5%	8234
	11th to 20th	Night	77% 6% 5% 5% 6% 1	8186
	21st to end	Night	68% 6% 6% 10% 10% 1	8401
February	1st to 10th	Night	65% 6% 10% 13% 6% 1	2730
	11th to 20th	Night	63% 4 8% 16% 8%	2665
	21st to end	Night	63% 5% 9% 16% 6% 1	2199
March	1st to 10th	Night	59% 5% 8% 13% 12% 4	5102
	11th to 20th	Night	55% 7% 15% 15% 7% 1	5090
	21st to end	Night	53% 5% 9% 18% 12% 2	5547
April	1st to 10th	Night	58% 5% 7% 18% 11% 2	2100
	11th to 20th	Night	50% 5% 8% 22% 14% 1	2044
	21st to end	Night	53% 6% 8% 17% 15% 2	1890
May	1st to 10th	Night	47% 7% 9% 21% 12% 3	4970
	11th to 20th	Night	42% 7% 11% 22% 16% 1	4640
	21st to end	Night	42% 6% 11% 25% 15% 1	5115
June	1st to 10th	Night	45% 7% 11% 19% 16% 1	1680
	11th to 20th	Night	39% 6% 12% 26% 16% 1	1658
	21st to end	Night	45% 7% 15% 21% 11% 1	1470
July	1st to 10th	Night	42% 7% 15% 22% 13% 1	3384
	11th to 20th	Night	37% 6% 12% 31% 14%	3552
	21st to end	Night	32% 6% 11% 37% 14%	3910
August	1st to 10th	Night	35% 6% 16% 25% 16% 1	2904
	11th to 20th	Night	43% 6% 17% 23% 10% 1	2902
	21st to end	Night	34% 6% 13% 34% 11% 2	3410
September	1st to 10th	Night	36% 8% 15% 27% 12% 1	2000
	11th to 20th	Night	34% 7% 13% 32% 14% 1	2041
	21st to end	Night	46% 5% 10% 26% 12%	2285
October	1st to 10th	Night	38% 6% 11% 28% 17%	3920
	11th to 20th	Night	50% 6% 14% 20% 9%	3899
	21st to end	Night	55% 6% 14% 18% 7%	4276
November	1st to 10th	Night	55% 5% 12% 20% 8%	2805
	11th to 20th	Night	57% 7% 13% 16% 7% 1	2940
	21st to end	Night	68% 6% 10% 11% 4	2940
December	1st to 10th	Night	74% 5% 10% 8% 3	4720
	11th to 20th	Night	73% 5% 7% 10% 5%	5348
	21st to end	Night	74% 4 5% 9% 7%	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	22% 26% 34% 14% 3 1	220
	11th to 20th	Day	26% 21% 37% 12% 3	234
	21st to end	Day	24% 22% 38% 13% 3	363
February	1st to 10th	Day	28% 29% 28% 11% 3	330
	11th to 20th	Day	28% 30% 35% 7%	330
	21st to end	Day	36% 21% 35% 8%	322
March	1st to 10th	Day	27% 20% 36% 14% 2	540
	11th to 20th	Day	28% 22% 31% 14% 3 1	540
	21st to end	Day	33% 20% 29% 13% 5%	594
April	1st to 10th	Day	31% 21% 30% 12% 5%	540
	11th to 20th	Day	38% 20% 20% 13% 6% 2	532
	21st to end	Day	31% 17% 33% 12% 6% 1	540
May	1st to 10th	Day	27% 19% 28% 17% 6% 3	543
	11th to 20th	Day	21% 17% 33% 17% 9% 2	567
	21st to end	Day	22% 19% 30% 17% 9% 3	617
June	1st to 10th	Day	23% 16% 32% 21% 6% 1	570
	11th to 20th	Day	19% 15% 33% 21% 9% 2	579
	21st to end	Day	21% 14% 34% 21% 8% 2	780
July	1st to 10th	Day	14% 9% 35% 30% 10% 3	596
	11th to 20th	Day	15% 11% 30% 28% 10% 4	524
	21st to end	Day	14% 12% 32% 29% 10% 3	576
August	1st to 10th	Day	15% 6% 30% 30% 14% 5%	526
	11th to 20th	Day	16% 8% 25% 33% 14% 5%	519
	21st to end	Day	18% 9% 33% 22% 12% 6%	583
September	1st to 10th	Day	18% 13% 28% 22% 14% 6%	530
	11th to 20th	Day	13% 10% 22% 22% 21% 11%	530
	21st to end	Day	23% 13% 27% 23% 11% 3	530
October	1st to 10th	Day	25% 16% 24% 18% 12% 4	530
	11th to 20th	Day	28% 23% 30% 14% 4 1	530
	21st to end	Day	34% 19% 29% 15% 3	575
November	1st to 10th	Day	35% 15% 32% 14% 4	285
	11th to 20th	Day	30% 26% 29% 12% 2 1	220
	21st to end	Day	35% 21% 35% 7% 1	220
December	1st to 10th	Day	30% 21% 32% 15% 2	220
	11th to 20th	Day	38% 26% 23% 11% 2	220
	21st to end	Day	35% 21% 29% 10% 3 1	242
January	1st to 10th	Night	26% 20% 35% 16% 3	840
	11th to 20th	Night	30% 17% 32% 16% 4 1	840
	21st to end	Night	20% 15% 38% 20% 6% 1	924
February	1st to 10th	Night	22% 22% 32% 21% 2	840
	11th to 20th	Night	22% 21% 36% 16% 4	823
	21st to end	Night	25% 23% 31% 18% 3	692
March	1st to 10th	Night	23% 20% 36% 18% 3	840
	11th to 20th	Night	23% 18% 35% 18% 4 1	840
	21st to end	Night	23% 15% 34% 20% 8%	924
April	1st to 10th	Night	29% 17% 31% 18% 4	840
	11th to 20th	Night	26% 16% 32% 18% 8% 1	800
	21st to end	Night	25% 12% 32% 22% 10%	630
May	1st to 10th	Night	23% 9% 27% 28% 13% 1	529
	11th to 20th	Night	20% 9% 33% 29% 8%	414
	21st to end	Night	15% 9% 34% 31% 11%	455
June	1st to 10th	Night	17% 8% 34% 31% 9% 1	420
	11th to 20th	Night	17% 11% 27% 35% 10%	420
	21st to end	Night	20% 8% 23% 36% 12%	420
July	1st to 10th	Night	10% 4 29% 40% 16%	390
	11th to 20th	Night	13% 5% 28% 35% 19% 1	388
	21st to end	Night	10% 5% 29% 37% 19%	479
August	1st to 10th	Night	13% 3 20% 36% 25% 2	597
	11th to 20th	Night	13% 5% 18% 37% 25% 2	594
	21st to end	Night	16% 7% 27% 29% 19% 1	769
September	1st to 10th	Night	14% 9% 29% 28% 17% 3	800
	11th to 20th	Night	16% 7% 22% 30% 21% 5%	800
	21st to end	Night	23% 10% 21% 28% 15% 3	800
October	1st to 10th	Night	21% 11% 29% 23% 15% 1	800
	11th to 20th	Night	29% 15% 29% 19% 7% 1	800
	21st to end	Night	31% 15% 29% 20% 4	880
November	1st to 10th	Night	29% 13% 28% 22% 7%	820
	11th to 20th	Night	26% 16% 35% 16% 6% 1	840
	21st to end	Night	33% 17% 28% 18% 4	840
December	1st to 10th	Night	32% 20% 31% 13% 5%	840
	11th to 20th	Night	26% 21% 35% 14% 3 1	840
	21st to end	Night	34% 17% 30% 15% 3	924

Page generated at 2026-06-28 02:10:43. Version ac07

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