Muncho Lake Provincial Park
Clear Sky Chart
History

This sumarizes the distribution of each different forecast outcome for the Muncho Lake Provincial 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	9% 13% 5% 12% 7% 7% 6% 5% 6% 7% 22%	135524
	Night	5% 12% 6% 13% 8% 7% 7% 6% 8% 8% 22%	136306
Transparency	Day	56% 9% 14% 15% 5%	135190
	Night	53% 10% 14% 16% 7% 1	136220
Seeing	Day	21% 13% 23% 23% 15% 5%	19256
	Night	14% 12% 22% 30% 19% 3	26721

By Month

Percentage Cloud Cover NW (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	2 10% 6% 14% 11% 10% 8% 7% 9% 11% 14%	2929
	11th to 20th	Day	1 10% 4 12% 9% 8% 6% 6% 9% 9% 25%	3180
	21st to end	Day	1 11% 6% 17% 7% 6% 6% 5% 9% 8% 24%	4529
February	1st to 10th	Day	2 11% 7% 11% 8% 7% 7% 5% 8% 9% 27%	1470
	11th to 20th	Day	1 13% 7% 18% 7% 5% 6% 4 7% 7% 26%	1732
	21st to end	Day	1 7% 5% 17% 10% 9% 7% 6% 8% 8% 21%	1557
March	1st to 10th	Day	1 9% 7% 13% 6% 6% 8% 7% 9% 8% 27%	4407
	11th to 20th	Day	1 9% 6% 19% 10% 10% 8% 6% 8% 8% 15%	5110
	21st to end	Day	1 11% 9% 18% 9% 6% 5% 4 6% 7% 25%	5690
April	1st to 10th	Day	3 14% 7% 18% 10% 8% 7% 5% 7% 6% 17%	2709
	11th to 20th	Day	2 17% 7% 15% 7% 6% 6% 5% 6% 7% 21%	2708
	21st to end	Day	5% 20% 7% 14% 8% 6% 5% 4 5% 6% 19%	3005
May	1st to 10th	Day	4 14% 6% 10% 7% 6% 6% 5% 7% 9% 26%	6930
	11th to 20th	Day	5% 18% 5% 12% 8% 8% 7% 5% 7% 8% 18%	7199
	21st to end	Day	10% 17% 4 10% 7% 7% 6% 5% 7% 7% 20%	8402
June	1st to 10th	Day	15% 16% 4 10% 6% 6% 5% 4 6% 7% 20%	3401
	11th to 20th	Day	19% 14% 4 11% 7% 6% 6% 3 5% 7% 18%	3400
	21st to end	Day	19% 12% 4 10% 6% 6% 6% 5% 6% 7% 18%	3400
July	1st to 10th	Day	19% 9% 3 8% 6% 6% 5% 4 6% 7% 26%	7700
	11th to 20th	Day	20% 10% 4 10% 7% 7% 6% 5% 6% 8% 17%	7700
	21st to end	Day	22% 10% 3 10% 7% 7% 5% 4 5% 7% 20%	7661
August	1st to 10th	Day	11% 8% 3 7% 5% 5% 6% 4 5% 7% 38%	4869
	11th to 20th	Day	16% 10% 3 8% 6% 5% 6% 4 5% 6% 30%	4689
	21st to end	Day	19% 17% 4 10% 6% 6% 6% 4 5% 5% 18%	4664
September	1st to 10th	Day	18% 16% 4 9% 6% 4 5% 4 5% 5% 24%	2557
	11th to 20th	Day	13% 17% 4 10% 7% 6% 6% 4 7% 6% 20%	2315
	21st to end	Day	11% 18% 5% 11% 8% 5% 5% 4 6% 6% 20%	2169
October	1st to 10th	Day	6% 18% 5% 12% 7% 6% 6% 5% 7% 8% 21%	3280
	11th to 20th	Day	6% 22% 6% 13% 7% 7% 7% 4 6% 6% 16%	2982
	21st to end	Day	4 14% 11% 11% 7% 6% 6% 5% 6% 7% 25%	2842
November	1st to 10th	Day	3 19% 7% 15% 5% 5% 6% 4 6% 8% 22%	1561
	11th to 20th	Day	1 17% 7% 15% 12% 9% 6% 6% 7% 7% 14%	1291
	21st to end	Day	1 10% 6% 15% 8% 7% 7% 4 9% 10% 22%	1260
December	1st to 10th	Day	3 20% 6% 13% 8% 9% 7% 5% 8% 7% 13%	1753
	11th to 20th	Day	1 9% 6% 16% 11% 9% 10% 7% 7% 8% 17%	1932
	21st to end	Day	9% 6% 13% 7% 6% 11% 9% 9% 9% 21%	2541
January	1st to 10th	Night	1 8% 4 15% 12% 9% 9% 8% 9% 8% 17%	9964
	11th to 20th	Night	2 12% 7% 12% 9% 7% 7% 6% 10% 9% 21%	9762
	21st to end	Night	1 12% 9% 15% 7% 7% 7% 6% 9% 7% 20%	9651
February	1st to 10th	Night	2 11% 5% 14% 9% 7% 7% 6% 7% 8% 23%	3150
	11th to 20th	Night	1 10% 7% 17% 8% 6% 5% 5% 6% 8% 26%	2773
	21st to end	Night	1 10% 5% 15% 11% 7% 8% 5% 6% 7% 24%	2249
March	1st to 10th	Night	1 8% 8% 12% 9% 8% 9% 7% 10% 8% 20%	5690
	11th to 20th	Night	8% 6% 18% 13% 10% 8% 6% 6% 7% 17%	5109
	21st to end	Night	1 11% 7% 14% 9% 8% 7% 6% 8% 10% 21%	5527
April	1st to 10th	Night	2 11% 7% 15% 9% 7% 6% 5% 7% 7% 24%	1909
	11th to 20th	Night	2 14% 6% 11% 7% 5% 7% 5% 8% 8% 27%	1861
	21st to end	Night	5% 18% 5% 12% 6% 5% 6% 6% 6% 8% 24%	1612
May	1st to 10th	Night	4 12% 4 9% 7% 7% 7% 6% 6% 9% 29%	3250
	11th to 20th	Night	5% 15% 5% 14% 9% 7% 6% 4 6% 7% 21%	2915
	21st to end	Night	9% 13% 3 9% 6% 6% 6% 6% 7% 9% 27%	2712
June	1st to 10th	Night	12% 13% 3 8% 7% 6% 6% 5% 7% 7% 27%	1000
	11th to 20th	Night	16% 11% 4 8% 6% 5% 6% 4 8% 8% 24%	1000
	21st to end	Night	16% 10% 4 7% 6% 4 5% 6% 8% 8% 27%	1000
July	1st to 10th	Night	17% 11% 3 7% 6% 4 4 3 4 8% 32%	2260
	11th to 20th	Night	15% 8% 4 10% 5% 6% 6% 4 7% 9% 25%	2260
	21st to end	Night	17% 10% 3 9% 6% 5% 6% 4 7% 6% 25%	3179
August	1st to 10th	Night	9% 6% 2 5% 4 4 4 3 5% 6% 52%	2281
	11th to 20th	Night	13% 8% 3 6% 4 4 4 4 6% 7% 41%	2356
	21st to end	Night	23% 14% 4 10% 6% 5% 5% 4 5% 5% 19%	3245
September	1st to 10th	Night	13% 12% 4 9% 5% 5% 5% 4 6% 7% 29%	1843
	11th to 20th	Night	12% 13% 3 10% 5% 6% 6% 6% 7% 9% 24%	2082
	21st to end	Night	9% 15% 4 9% 6% 6% 6% 5% 7% 8% 24%	2231
October	1st to 10th	Night	8% 18% 5% 12% 7% 7% 6% 4 5% 6% 23%	3920
	11th to 20th	Night	6% 18% 6% 12% 6% 6% 6% 4 6% 8% 22%	4166
	21st to end	Night	5% 15% 9% 14% 7% 8% 7% 5% 7% 7% 17%	4948
November	1st to 10th	Night	4 17% 6% 13% 7% 6% 6% 4 6% 8% 23%	2954
	11th to 20th	Night	2 13% 8% 16% 10% 7% 8% 4 7% 8% 16%	3308
	21st to end	Night	2 11% 6% 15% 8% 7% 7% 7% 7% 8% 22%	3360
December	1st to 10th	Night	3 17% 4 14% 9% 8% 7% 7% 9% 8% 15%	5642
	11th to 20th	Night	1 11% 7% 15% 9% 9% 9% 6% 8% 8% 18%	6480
	21st to end	Night	1 9% 5% 14% 8% 8% 9% 7% 8% 9% 22%	8657

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	53% 12% 9% 13% 10% 3	2929
	11th to 20th	Day	50% 7% 18% 15% 10% 1	3196
	21st to end	Day	52% 9% 13% 17% 8% 1	4530
February	1st to 10th	Day	50% 8% 12% 17% 11% 1	1470
	11th to 20th	Day	54% 9% 13% 16% 7% 1	1740
	21st to end	Day	55% 8% 12% 18% 6% 2	1557
March	1st to 10th	Day	46% 8% 7% 23% 15%	4407
	11th to 20th	Day	59% 10% 11% 14% 6%	5110
	21st to end	Day	54% 10% 11% 16% 8%	5690
April	1st to 10th	Day	63% 8% 11% 14% 4	2709
	11th to 20th	Day	60% 6% 12% 17% 5%	2708
	21st to end	Day	64% 6% 13% 14% 2	3005
May	1st to 10th	Day	49% 9% 16% 18% 8%	6930
	11th to 20th	Day	60% 8% 13% 16% 4	7203
	21st to end	Day	58% 9% 12% 17% 4	8403
June	1st to 10th	Day	60% 6% 14% 17% 3	3401
	11th to 20th	Day	65% 6% 13% 13% 3	3400
	21st to end	Day	63% 7% 15% 13% 2	3400
July	1st to 10th	Day	53% 9% 18% 18% 2	7616
	11th to 20th	Day	60% 13% 19% 7% 1	7607
	21st to end	Day	58% 11% 17% 13% 1	7446
August	1st to 10th	Day	43% 8% 13% 22% 14%	4851
	11th to 20th	Day	49% 9% 16% 21% 5%	4734
	21st to end	Day	66% 8% 12% 11% 3	4663
September	1st to 10th	Day	61% 8% 12% 14% 4	2557
	11th to 20th	Day	61% 8% 14% 15% 2	2315
	21st to end	Day	61% 8% 13% 14% 3	2169
October	1st to 10th	Day	56% 10% 17% 13% 4	3280
	11th to 20th	Day	66% 9% 13% 11% 2	2982
	21st to end	Day	55% 9% 18% 14% 4	2842
November	1st to 10th	Day	58% 7% 13% 17% 5% 1	1561
	11th to 20th	Day	64% 8% 10% 12% 5%	1291
	21st to end	Day	53% 8% 14% 16% 7% 1	1260
December	1st to 10th	Day	64% 10% 10% 13% 2	1753
	11th to 20th	Day	57% 11% 10% 15% 6% 1	1934
	21st to end	Day	44% 14% 17% 16% 7% 2	2541
January	1st to 10th	Night	51% 11% 11% 14% 10% 3	9965
	11th to 20th	Night	51% 10% 12% 15% 11% 1	9808
	21st to end	Night	55% 10% 13% 16% 6%	9651
February	1st to 10th	Night	54% 8% 8% 16% 12% 2	3150
	11th to 20th	Night	53% 7% 15% 15% 9% 1	2776
	21st to end	Night	54% 7% 11% 17% 10% 2	2249
March	1st to 10th	Night	46% 12% 10% 18% 13% 1	5690
	11th to 20th	Night	58% 10% 10% 15% 6%	5110
	21st to end	Night	50% 12% 12% 17% 8%	5527
April	1st to 10th	Night	55% 8% 13% 20% 5%	1909
	11th to 20th	Night	51% 7% 14% 18% 9%	1861
	21st to end	Night	55% 8% 17% 17% 3	1612
May	1st to 10th	Night	42% 13% 16% 23% 5% 1	3247
	11th to 20th	Night	59% 8% 16% 14% 4	2915
	21st to end	Night	49% 10% 12% 22% 7%	2712
June	1st to 10th	Night	53% 7% 15% 22% 3	1000
	11th to 20th	Night	53% 8% 17% 18% 3	1000
	21st to end	Night	50% 10% 21% 16% 3	1000
July	1st to 10th	Night	48% 8% 22% 19% 3	2235
	11th to 20th	Night	51% 12% 27% 10% 1	2230
	21st to end	Night	52% 12% 21% 13% 1	3089
August	1st to 10th	Night	32% 5% 15% 29% 18%	2274
	11th to 20th	Night	40% 8% 22% 25% 5% 1	2377
	21st to end	Night	65% 8% 14% 12% 1	3245
September	1st to 10th	Night	53% 8% 16% 16% 6% 1	1843
	11th to 20th	Night	54% 8% 19% 17% 2	2082
	21st to end	Night	55% 9% 16% 16% 4	2231
October	1st to 10th	Night	58% 9% 14% 17% 3	3920
	11th to 20th	Night	58% 8% 16% 17% 1	4166
	21st to end	Night	60% 10% 14% 12% 4	4948
November	1st to 10th	Night	54% 9% 15% 16% 4 2	2954
	11th to 20th	Night	60% 10% 10% 14% 5%	3308
	21st to end	Night	54% 9% 12% 16% 7% 2	3360
December	1st to 10th	Night	58% 11% 12% 13% 6%	5642
	11th to 20th	Night	55% 11% 11% 17% 5%	6477
	21st to end	Night	47% 13% 16% 16% 7% 1	8657

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	12% 6% 21% 31% 20% 9%	220
	11th to 20th	Day	16% 10% 20% 26% 19% 8%	220
	21st to end	Day	19% 15% 20% 26% 17% 2	242
February	1st to 10th	Day	14% 11% 28% 31% 13% 2	220
	11th to 20th	Day	16% 14% 27% 24% 13% 6%	418
	21st to end	Day	11% 17% 30% 25% 12% 5%	355
March	1st to 10th	Day	9% 14% 31% 23% 16% 7%	447
	11th to 20th	Day	12% 12% 29% 25% 16% 6%	540
	21st to end	Day	10% 14% 27% 27% 17% 5%	594
April	1st to 10th	Day	13% 15% 32% 24% 11% 5%	540
	11th to 20th	Day	13% 15% 30% 22% 14% 5%	532
	21st to end	Day	18% 15% 30% 21% 12% 4	605
May	1st to 10th	Day	18% 14% 29% 19% 15% 4	753
	11th to 20th	Day	15% 9% 22% 26% 21% 7%	906
	21st to end	Day	20% 11% 20% 21% 20% 8%	1072
June	1st to 10th	Day	24% 10% 19% 23% 17% 6%	931
	11th to 20th	Day	27% 11% 17% 25% 16% 5%	930
	21st to end	Day	21% 11% 18% 22% 21% 7%	930
July	1st to 10th	Day	26% 8% 18% 26% 17% 6%	916
	11th to 20th	Day	28% 10% 17% 21% 17% 6%	912
	21st to end	Day	27% 11% 20% 23% 16% 4	860
August	1st to 10th	Day	23% 9% 18% 25% 18% 7%	726
	11th to 20th	Day	33% 16% 23% 17% 9% 2	665
	21st to end	Day	30% 15% 19% 20% 13% 4	583
September	1st to 10th	Day	31% 17% 18% 20% 10% 4	530
	11th to 20th	Day	25% 15% 25% 20% 12% 3	530
	21st to end	Day	33% 19% 23% 15% 8% 2	530
October	1st to 10th	Day	29% 18% 22% 19% 11% 1	530
	11th to 20th	Day	22% 19% 30% 17% 10% 2	435
	21st to end	Day	17% 17% 22% 25% 14% 4	242
November	1st to 10th	Day	17% 14% 24% 23% 18% 5%	220
	11th to 20th	Day	9% 15% 22% 33% 16% 6%	220
	21st to end	Day	12% 13% 22% 32% 13% 8%	220
December	1st to 10th	Day	12% 20% 27% 22% 16% 3	220
	11th to 20th	Day	11% 11% 26% 31% 15% 6%	220
	21st to end	Day	11% 7% 19% 31% 24% 9%	242
January	1st to 10th	Night	7% 11% 27% 34% 17% 3	1160
	11th to 20th	Night	14% 17% 24% 29% 14% 3	1095
	21st to end	Night	14% 14% 27% 29% 14% 2	1045
February	1st to 10th	Night	11% 13% 23% 36% 16% 2	950
	11th to 20th	Night	9% 12% 27% 32% 17% 2	882
	21st to end	Night	7% 12% 23% 35% 20% 3	692
March	1st to 10th	Night	7% 11% 28% 33% 18% 4	840
	11th to 20th	Night	7% 10% 31% 34% 17% 2	840
	21st to end	Night	7% 9% 23% 32% 22% 7%	924
April	1st to 10th	Night	9% 10% 22% 31% 23% 6%	649
	11th to 20th	Night	10% 9% 20% 33% 23% 6%	613
	21st to end	Night	17% 8% 21% 31% 21% 2	420
May	1st to 10th	Night	15% 8% 20% 32% 20% 4	420
	11th to 20th	Night	17% 4 14% 33% 30% 2	414
	21st to end	Night	18% 9% 13% 25% 28% 8%	455
June	1st to 10th	Night	19% 7% 13% 30% 29% 3	400
	11th to 20th	Night	21% 6% 13% 25% 31% 4	400
	21st to end	Night	20% 6% 15% 21% 34% 4	400
July	1st to 10th	Night	22% 7% 14% 28% 26% 3	390
	11th to 20th	Night	22% 8% 14% 24% 29% 4	388
	21st to end	Night	14% 7% 16% 29% 30% 4	438
August	1st to 10th	Night	19% 5% 12% 23% 36% 5%	398
	11th to 20th	Night	21% 11% 19% 30% 17% 2	397
	21st to end	Night	26% 10% 12% 25% 23% 3	660
September	1st to 10th	Night	22% 11% 17% 27% 19% 4	643
	11th to 20th	Night	20% 13% 20% 27% 17% 4	800
	21st to end	Night	25% 19% 20% 23% 11% 2	800
October	1st to 10th	Night	24% 13% 20% 28% 13% 1	800
	11th to 20th	Night	18% 18% 25% 26% 11% 2	800
	21st to end	Night	16% 13% 24% 28% 16% 3	880
November	1st to 10th	Night	15% 12% 22% 32% 16% 2	864
	11th to 20th	Night	10% 14% 24% 31% 18% 3	1108
	21st to end	Night	14% 11% 27% 32% 16% 2	1160
December	1st to 10th	Night	15% 16% 28% 28% 12% 2	1160
	11th to 20th	Night	9% 11% 24% 35% 16% 5%	1160
	21st to end	Night	9% 12% 21% 32% 21% 6%	1276

Page generated at 2026-05-28 23:53:25. Version ac07

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