Weather, July 1806
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Aug 30, 1803 Sep 30, 1806

Weather, July 1806

Day of
State of the
weather at
☉ rise

Wind at
☉ rise
State of the
weather at
4 P. M.

Wind at
4 P. M.
1st c a f N W f N W
2cd f S E f S E
3rd f S E f N W
4th f S E f N W
5th f N E f S W
6th f N E f S W
7 c a r T & L. S W c a f & r W
8th f S W f W.
9th c a r N. E. r. N. E.
10th f a r N W. f W.
11th f N W f N. W.
12th f N W f N W
13th f N E f N E
14th f S W f S W
15th f S W f E
16th f S W f S W
17th f a T L S W f S W
18th f S W f N E
19th f S E f N E
20th f E f N.
21st f N. f N. E.
22cd f S E f N. E.
23rd f a T & L S E f S W
24th c a r T & L N W c a r t L N W.
25th c a r N W c a r N W
26th c a r N f N W
27th f N W f S W
28th f a r T & L. N E c a f h r T & L N E
29th r a r T & L— S W c a r N E
30th r a r N E r N E
31st c a r N E r N W
[Remarks] [2]
1st a speceis of wild clover with a small leaf just in blume.
3rd the turtle dove [3] lays it's eggs on the ground in these plains and is now
seting, it has two eggs only and they are white.
5th a great number of pigeons breeding in this part of the mountains
musquetoes not so troblesome as near Clark's river.    some ear flies [4]
of the common kind and a few large horse flies. [5]
6th the last night cold with a very heavy dew.
7 a cloud came on about sunset and continued to rain moderately all
night.    rained at 3 P. M.
8th heavy white frost last night.    very cold.
9th rained slightly last night.    air cold.    rained constantly all day    air
extreemly cold    it began to rain about 8 A. M. and continued with
but little intermission all day    in the evening late it abated and we ob-
tained a view of the mountains we had just pased    they were covered
with snow apparrently several feet deep which had fallen during this
10th rain ceased a little after dark.
11th wind very hard in the latter part of the day
12th wind violent all last night and today untill 5 P. M. when it ceased in
some measure
16th Saw the Cookkoo or rain crow and the redheaded woodpecker. [6]    the
golden rye [7] now heading.    both species of the prickly pare [8] in
blume.—    the sunflower in blume.
17th wind violent all day.    distant thunder last evening to the West.
23rd a distant thundercloud last evening to the west.    mountains covered
with snow.
24th a violent gust of thunder Lightning last evening at 6 P. M.    rain and
wind all night untill this evening with some intervales.
25th rained and wind violent all day and night.
26th wind violent    rain continues.
28th a thundershower last night from N. W. but little rain where we were.
heavy hail storm at 3 P. M.    the prickly pear has now cast it's blume
29th heavy rain last night, continued with small intervales all night
30th rained almost without intermission
31st   do         do        do         do

Day of
the month
State of
the weather
at Sun rise

Wind at
Sun rise
State of
the weather
at 4 P. M

Wind at
4 P M.
1st c a f N W f. N W
2cd f. S E f N. W
3rd f. S E f S W
4th f. S W f. S W
5th f. N. E. f. S W.
6th f. S W. c. a. r. T. & L S W
7th c. a. r W. f. a. r S W by W
8th f. a. r W. f. S W
9th c. S W. f. S W
10th f. S. E. f. S W.
11th f. S E f. N N E
12th f. S E. f. N W
13th f. S S E f. N E
14th f. N W f. N W
15th f. S E. by E f. N E
16th c. N E c. N. E
17th f. a. r. h. T. & L. S E f. S W
18th f. S W f. S E
19th f. N W f. S E
20th f. N E f. N E
21st f. N E c. N. E.
22nd f. a. T. L & r N E c. N. E
23rd f. N. E. c. S E
24th f. S W r. S W.
25th c. E c. a r S W
26th c. S S W f a. r. N W.
27th f. N. E. f. S W.
28th C a f r N E f. N. W.
29th c. a. r. T. & L N. E f. N.
30th f. a. r. T. L N. W. f. a. r. S. E
31st f. N W. c. a. r N E
[Remarks] [9]
1st a Species of wild Clover in blume
2nd Musquetors very troublesom
3rd Cap L. & my Self part at Travellers rest.
4th a worm day. I saw a Speces of Honeysuckle [10] with a redish brown
flower in blume
5th Cool night. Some dew this morning [11]    the nights are Cool.    the
musquetors are troublesome untill a little after dark when the
air become Cool and Musquetoes disappear.
6th cold night with frost. I slept cold under 2 blankets on head of
Clarks river. I arived in an open plain in the middle of which a
violent Wind from the N W. accompanied with hard rain which
lasted from 4 untill half past 5 P. M.    quawmash in those plains
at the head of wisdom River is just begining to blume and the
grass is about 6 inches high.
7th Saw a blowing Snake. [12]    a violent rain from 4 to ½ past 5 last
evening & Some rain in the latter part of last night.    a small
Shower of rain at 4 this morning accompanied with wind from
the S. S. W.
8th a Small Shower of rain a little after dark    a heavy rain and
wind from S W. at 4 P. M yesterday [13]    a heavy Shower of rain
accompanied with rain from the S W. from 4 to 5 P M.    passed
the boiling hot Springs emerced 2 peces of raw meat in the
Spring and in 25 Minits the Smallest pece was sufficiently cooked
and in 32 the larger was also sufficiently cooked
9th Hard frost. Some ice this morning.    last night was very Cold
and wind hard from the N E. all night. The river is 12 inches
higher than it was last Summer when we made the deposit here
and portage from this place.    more Snow on the adjacent moun-
tains than was at that time.
10th white frost this morning.    ice ¾ of an inch thick on Standing
water.    grass killd by the frost.    river falling proceviable.    a
large white frost last night.    the air extreemlly Cold. Ice ¾ of
an inch thick on Standing water.
11th frost this morning.    goslins nearly grown    fishing hawks [14] have
their young    The yellow Current nearly ripe.    a Slight frost
last night.    the air Cool.    the Musquetors retired a little after
dark, and did not return untill about an hour after Sunrise.
12th wisdom river is high but falling. Prickly pears in blume
14th Saw a Tobaco worm [15] shown me by York
15th Struck the river Rochejhone 120 yds wide    water falling a little
16th Saw the wild indigo & common sunflower
17th Heavy showers of rain    Hard Thunder & Lightning last night
a heavy Shower of rain accompanied with hail Thunder and
Lightning at 2 a. m. with hard wind from the S W.    after the
Shower was over it Cleared away and became fair.
18th yellow, purple, & black Currents ripe and abundant
19th Saw the 1st Grape vine [16] of the dark purple kind    the grape
nearly grown
20th Sworms of grass hoppers have eaten the grass of the plains for
many miles. The River Rochejhone falls about ½ an in in 24
hours and becoms much Clearer than above. The Grass hop-
pers are emencely noumerous and have distroyed every Species
of grass from one to 10 Miles above on the river & a great dis-
tance back.
21st river falls a little and the water is nearly Clear
22nd raind Slightly last evening about dark with hard winds Thun-
der & lightning    a fiew drops of rain last night at dark.    the
Cloud appd. to hang to the S W, wind blew hard from different
points from 5 to 〈7〉 8 P M which time it thundered and Light-
ened. The river by 11 a. m. to day had risen 15 inches, and the
water of a milky white Colour.
23rd violent wind last night from S W. The river has fallen within the
last 24 hours 7 inches.    the wind was violent from the S W for
about 3 hours last night from the hours of 1 to 3 A. M.
24th Violent wind last night.    river falling a little    Since the last rise
it had fallen 13 inches.    river falling a little    it is 6 feet lower
than the highest appearance of it's rise. Rained from 3 to 4 P M
but Slightly.    the wind violent from the S. W.    (Sgt. Pryor
crossd and Set out for the Mandans.[)]
25th rained from 3 to 4 P M yesterday but Slight.    rained Several
Showers    Several Showers of rain with hard winds from the S
and S W the fore part of the day.    the brooks on each Side are
high and water muddye.
26th a Slight Shower this morning with hard wind from the S. W.
The river falling, but very Slowly 1 inch in 24 hs.
27th Saw a flight of gulls, [17] a Small rattle Snake [18] Several flocks of
Crows & black burds. [19]
28th a fiew drops of rain this morning a little before day light.    river
Still falling a little    Bratten Coet [caught] a beaver    Labeech
Shot 2 last evenig. I saw a wild Cat [20] lying on a log over the
29th [21] a fiew drops of rain accompanied with hard Claps of Thunder
and Sharp lightning last night    wind hard from the N. E.
30th Great number of Swallows, [22] they have their young. Killed 1s
black tail deer.    young gees beginning to fly    a Slight Shower
of rain accompanied with thunder and lightning. Several Show-
ers in the course of this day.    it cleared away in the evening and
became fair    river falling a little. Great quantities of Coal ap-
pear in the bluffs on either Side. Some appearance of Burnt
hills at a distance from the river. [23]
31st rained only a fiew drops last night.    a Small Showers to day.
wind hard from the N E    The wind blew hard and it was Show-
ery all day tho not much rain.    the clouds came up from the W.
and N W frequently in course of the day.
1. Since Lewis and Clark separated on July 3 and were apart for the rest of the month, their weather observations for most of the month are unrelated; therefore they appear separately, without notice of discrepancies. Lewis's table is in Codex L, pp. 146, 148 (reading backwards). Coues's penciled page number for 148 is mislabeled as "page 147." Clark's weather table for July 1806 appears in Codex M, pp. 147–49 (reading backwards). (back)
2. Lewis's remarks in Codex L appear both in the margin of his weather table and separately. (back)
3. The mourning dove. (back)
4. Probably deer fly, Chrysops sp. (back)
5. Horse fly, Tabanus sp. (back)
6. Red-headed woodpecker, Melanerpes erythrocephalus [AOU, 406]. (back)
7. Some unknown species of Elymus. (back)
8. See Lewis's entry of July 10, 1806. (back)
9. Clark has remarks in both the margin of his weather table and separately. There is an unusual amount of repetition between the two setes of remarks, as the reader will note. Some duplication has been omitted without comment. (back)
10. Perhaps orange honeysuckle. (back)
11. The separate remark begins "a dew this morning.    the nights are Cool," then continues with "the musquetors." (back)
12. Perhaps western hog-nosed snake, Heterodon nasicus. Burroughs, 276–77; Coues (HLC), 2:435 n. 23. (back)
13. Clark's marginal comments for July 8 and 9 run together and are separated at what appears to be a logical point. (back)
14. Osprey, Pandion haliaetus [AOU, 364]. (back)
15. Probably tobacco hornworm, Manduca sexta. (back)
16. Some unknown wild grape, Vitus sp. (back)
17. Any of several species of Larus. (back)
18. Probably the prairie rattlesnake. (back)
19. The common, or American, crow, Corvus brachyrhynchos [AOU, 488]. Without the size given, the blackbirds are not identifiable. (back)
20. Probably the bobcat, Lynx rufus. (back)
21. The marginal remark reads, "rain Slightly with Thunder and lightning." (back)
22. Probably the barn swallow, Hirundo rustica [AOU, 613]. Holmgren, 33. (back)
23. Geology notes to these references are found under Clark's entry of this date, July 30, 1806. (back)